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^LOSSES

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AGRICULTURE,

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Agriculture Handbook No. 291

Agricultural Research Service

UNITED STATES DEPARTMENT OF AGRICULTURE
m^''

I UNITED STATES DEPARTIffiNT OF AGRICULTURE

Agricultural Research Service

Washington, D.C. 20250 April I966

Errata for Agriculture Handbook No. 291

"Losses in Agriculture"

Page 5î The second line of footnote 1, table 2, should read " the loss

in quantity and value are based on the quantity and average

prices "

The seventh line of footnote 2, table 2, should read " would

be available for additional production with no "

Page 120_j^ In the second column of table 59f the fourth entry should be

Ï 3,812,406 instead of 3,312,906 and the first total should be J

1¿J-,771,687 instead of 1'+,272,187. |

I
USDA, National Agricultural Library

NAL Bidg

7 10301 Baltimore BIvd

Beltsviüe, MD 207ÛS-2351

L LOSSES

IN

A<jRICULTURE %

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Agriculture^Händbook No. 291 //,

^. /'[(.S^ Agricultural JResearch Service

UNITED STATES DEPARTMENT OF AGRICULTURE

WashingtorL, D.C. Issued August 1965^

For sale by the Superintendent of Documents, U.S. Government Printing Office

Washington, D.C. 20402 Price 60 cents
PERSONNEL INVOLVED IN PREPARATION OF THIS HANDBOOK

This handbook was prepared under the general guidance of a committee appointed by the Administrator of the Agricultural Research Service

in 1962. The committee included representatives of agencies concerned

with losses in agriculture. The members were :

H. R. Adams, Soil Conservation Service

M. E. Bailey, Statistical Reporting Service

C. E. Burkhead, Statistical Reporting Service

H. T. Cook, C. D. Van Houweling, and R. J. Anderson, Agricultural

Research Service

James Vermeer, Economic Research Service

R. C. Wilson, Forest Service

E. L. LeClerg, Agricultural Research Service, chairman

A working group (coordinators), consisting of representatives from

each of the agencies, assisted the chairman of the committee in the details

of securing the estimates of losses and text material. The members were :

Agricultural Research Service

Proctor Campbell, Utilization Research and Development Division

Walter M. Carleton, Agricultural Engineering Research Division

H. T. Cook, Market Quality Research Division

Kelvin Dorward, Plant Pest Control Division

Ned R. Ellis, Animal Husbandry Research Division

gierre-GhÄloux, Animal Disease Eradicatioj;! Division

Frank Enzie, Animal Disease and Parasite Research Division

Lewis W. Erdman, Soil and Water Conservation Research Division

Edward Murphy, Meat Inspection Division

H. Rex Thomas, Crops Research Division

Arlo M. Vance, Entomology Research Division

R. C. Wilson

H. R. Adams

Forest Service

Soil Conservation Service

The chairman was responsible for calculating losses in quantity and

value for each kind of loss reported. In addition, he assembled the various

tables and reviewe4j:h^j£XJLmaterial submitted by the various agencies in

support of théiFestimates.

II
1939G4

FOREWORD

The pepartment of Agriculture from time to time receives requests for

information on the losses incurred in the production, processing, transportation, and marketing of farm and forest products. To answer these

requests, the Department issued in June 1954, ARS-20-1, "Losses in

Agriculture: A Preliminary Appraisal for "Review/' Estimates in that

publication, which for the most part represented average annual losses

for the period 1942-51, have been reviewed and brought up to date for

this handbook. — —

^ ^The estimates in this handbook are based on average prices for the

period 1951-60. Some of the estimates are based on surveys or actual

records r "most, however, represent the best judgment of Department

specialists.

Dollar values were placed on the losses because the monetary value of

the losses is the only common measure that could be used. The dollar values

represent losses to the public — not to farmers. No consideration was

given to lower prices that might have resulted from the larger volume of

products that would have been available had these losses not occurred.

The higher estimates for losses in this bulletin, as compared with those

in the previous report, are the result of several factors including (1) higher

prices for farm products; (2) greater volume of production and, therefore, greater opportunity for losses; (3) larger number of losses reported;

and (4) a better basis for estimating losses.

George W. Irving, Jr., Administrator

Agricultural Research Service

III
PRECAUTIONS

Pesticides are poisonous to man and animals. Use them only when

needed and handle them with care. Follow the directions and heed all

precautions on the labels.

Keep pesticides in closed, well-labeled containers in a dry place. Store

them where they will not contaminate food or feed, and where children and

pets cannot reach them.

Avoid repeated or prolonged contact of pesticide with your skin.

Avoid spilling it on your skin, and keep it out of your eyes, nose, and mouth.

If you spill any on your skin, wash it off with soap and water.

After handling a pesticide, do not eat or smoke until you have washed

you hands and face. Wash your hands and face immediately after applying pesticide.

When handling pesticides, wear clean, dry clothing. If you spill

pesticide on your clothing, launder the clothing before wearing it again.

Do not inhale pesticide dusts or mists.

To protect fish and wildlife, do not contaminate lakes, streams, or ponds

with pesticide. Do not clean spraying equipment or dump excess spray

material near such water.

To minimize losses of honey bees and other pollinating insects, apply

insecticide, when possible, during hours when the insects are not visiting

the plants. Avoid drift of insecticide into bee yards.

Also avoid drift of pesticide to nearby crops or livestock.

Empty containers are particularly hazardous. Burn empty bags and

cardboard containers in the open or bury them. Crush and bury bottles

or cans.

Trade names are used in this publication solely to provide specific information. Mention of a trade name does not constitute a guarantee or

warranty of the product by the U.S. Department of Agriculture or an

endorsement by the Department over other products.

IV
CONTENTS

Page

Chapter 1.—Introduction 1

Economic effects of losses 1

Procedures 1

Meaning of estimates 2

Chapter 2.—Diseases of crop and ornamental plants 3

Field crops 4

Alfalfa and all other hay plants 14

Forage plants grown for seed 15

Pasture and rangeland plants 16

Fruit and nut crops 17

Vegetable crops 23

Ornamental plants and shade trees 31

Crop losses from air pollutants 34

Chapter 3.—Nematode damage to crop

plants 36

Field and forage crops 36

Fruit crops 38

Vegetable crops 38

Chapter 4.—Injurious crop insects 40

Field crops 41

Forage and seed crops and rangelands. . 45

Turf 46

Fruit and nut crops 46

Vegetable crops 49

Landscape flowers and ornamentals ... 53

Horticultural specialties 53

Loss to honey bee industry 54

Chapter 5.—Weeds 55

Field crops 55

Forage-seed and grazing crops 58

Fruit and nut crops 60

Vegetable crops 62

Chapter 6.—Ineflicient farm operations

and fire 66

Excessive pesticide application 66

Improper fertilizer placement 66

Improper planting 66

Improper root pruning 66

Chapter 7.—Harvesting and storage losses. 67

Harvesting losses 67

Storage losses 69

Page

Chapter 8.—Livestock and poultry losses.. 72

Infectious diseases 72

Noninfectious diseases and nutritional

disorders 72

Internal parasites of livestock and

poultry 78

Insect pests of livestock and poultry .. 81

Chapter 9.—Marketing and processing

losses 85

Marketing fruits and vegetables 85

Fruits and vegetables in retail stores . . 89

Processing crops 89

Marketing and processing poultry and

poultry products 93

Meat and poultry condemnations 94

Chapter 10.—Forest resources and forest

products losses 95

Fire losses 95

Insect losses 95

Disease losses 97

Other losses 97

Chapter 11.—Soil and water losses 98

Erosion, water, and unfavorable soil

conditions 98

Weeds in aquatic and noncrop areas ... 103

Chapter 12.—Cost of controlling losses and

of inspection and quarantine services 105

Animal-disease eradication programs .. 105

Animal inspection and quarantine programs 106

Cooperative plant pest control programs 107

Controlling erosion in 17 Western States 107

Controlling fire, insects, and disease in

forests 108

Controlling insects affecting crops, man,

animals, and households 109

Controlling insects in stored products . . 109

Controlling nematodes 110

Controlling plant diseases 110

Plant quarantine and regulatory measures Ill

Controlling weeds HI

Chapter 13.—Summary 119
LOSSES IN AGRICULTURE

Chapter 1.-Introduction

Losses in agriculture are of two types: (1)

reduction in quantity or quality during production, handling, and processing of farm and

forest products; and (2) deterioration in land

that affects production immediately or over a

period of years. Another source of loss represents the labor and materials required to

control such factors as pests, soil erosion, and

water loss.

This handbook provides information on the

extent of some of these losses. It does not include losses in production and productive

efficiency caused by differences in the utilization of the land, such as growing less productive crops than might have been grown, or

avoiding a crop because of possible loss from

some pest. It does, however, include estimates

of losses resulting from failure to use recommended production practices or techniques.

Information on losses can be used in planning and administering agricultural research

and control programs. Certain kinds of loss

data can be used to direct extension activities

to problems of greatest economic importance.

In addition, information on sources of losses is

of value to farmers, processors, and marketers

of agricultural products. Manufacturers and

distributors of agricultural chemicals base

their programs, in part at least, on losses in

crop commodities and livestock and poultry.

ECONOMIC EFFECTS OF LOSSES

Losses in agricultural production have two

kinds of economic effects : (1) they increase the

cost of production; and (2) they reduce the

quantity and, in some instances, the quality of

products available to consumers. From another

viewpoint, consumer needs could be more fully

satisfied and better nutrition provided with the

same resources and expenditures if the causes

of loss were not present.

The possibility of profitably reducing or

eliminating agricultural losses is influenced by

technological developments. Technological developments may affect either the cost of production or the value of the product. The discovery of more effective or lower cost agricultural chemicals and of more efficient methods

of application, for example, may make possible

either larger production of higher quality goods

at little or no increase in cost to farmers or the

same production with the use of fewer resources

and at a lower cost. On the other hand, the

discovery of new or improved uses for products may increase their total value with little

or no change in resources used or in production costs.

Some methods of reducing or eliminating

losses may not increase operating costs. For

example, while development of a more effective

agricultural chemical may require substantial

funds for research, the new chemical may be

no more expensive to manufacture and apply

than those previously used.

Some losses may be difficult to reduce or

eliminate. For example, it may be impossible

to find ways of completely eliminating losses

to crops and livestock caused by some pests.

And, even if it were possible, the cost of control

might be high in relation to the increase in

quantity or quality of the product.

PROCEDURES

Nature of estimates

Estimates of losses are included in this handbook, whether or not they arise from causes

that are preventable with present technical

knowledge. However, complete estimates of

all losses could not be obtained. The loss estimates are limited to the more economically

important factors.

Computation of fosses

The losses during production of crops and

animals are expressed as annual production

lost in terms of (1) quantity and (2) value.

Estimates of losses in quantity (bushels, tons,

etc.) indicate the extent to which national production of each product would have increased

had the cause of the loss been eUminated. Estimates of losses in value are based on average

prices received by farmers. Estimates of losses

in quality are included in estimates of losses

in value.

The losses shovra in the tables are based in

most instances on national annual averages,

chiefly for 1951-60. Because of wide variations

in some kinds of losses from year to year, it was

considered desirable to use an average for the

10 years rather than data for a single year. In

some instances, lack of information on which to

base estimates for the 10-year period made it
AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

necessary to use a shorter and more recent

period. These data are footnoted in the tables.

Losses were computed as follows :

Losses During Production. — Percentage

losses from potential production were estimated

for losses to crops caused by insects, diseases,

nematodes, and weeds; and during harvesting

operations; and for losses to livestock and

poultry caused by insects and diseases. The

procedure used is a modification of that reported in the Plant Disease Reporter.^ Since

more than one causal factor may affect a crop

or an animal species at the same time, an

average potential was estimated assuming all

known losses were eliminated. The loss caused

by each factor was then taken as the product of

the average potential and the estimated percentage loss.

Estimates of losses in quality of commodities

produced (crops and farm animals) are included in the computation of losses in value.

Losses Following Production. — Losses to

crops and other commodities in storage on

farms, in transit, during processing, and in

marketing channels were also measured in

terms of quantity, quality, and value lost. However, the appropriate quantities and values

were multiplied directly by the estimated loss

percentages to obtain the two measures of

average annual losses.

How estimates were obtained

Estimates of losses were based on surveys

and records where possible. However, surveys

and records were not available for many losses,

and estimates are based on judgment of

specialists in the different natural science fields.

But even the information that these specialists

¡HESTER, K. STARR, PLANT DISEASE LOSSES: THEIR

i>PRAISAL AND INTERPRETATION. U.S. Dept. A^., AgT.

Res. Serv. Plant Disease Reporter, Supplement 193

(1950) : 191-362.

had available was limited; consequently, the

accuracy or reliability of the estimates differs

greatly.

Each member of the working group assembled the estimates obtained from specialists

within his agency. Most of the estimates are

applicable to national data on production and

resources.

Adding percentage loss estimates from different causes affecting the same product so as

to avoid duplication or overestimating presented a special problem. It was assumed that

percentage loss estimates could be added when

they were low and from closely related causes,

such as diseases affecting the same crop.

The Statistical Reporting Service supplied

most of the data on quantity and farm value of

production and other basic data to which percentage loss estimates were applied to obtain

national estimates of losses.

MEANING OF ESTIAAATES

In interpreting the estimates of losses in

this handbook, it is essential to recognize the

assumptions on which they are based.

The estimates indicate not only preventable

reductions in production but also, in some cases,

those not avoidable with present technical

knowledge.

The estimates evaluate the annual production at the prevailing average farm prices from

1951 to 1960. This does not necessarily mean

that the farmers' cash income would have been

increased to that extent if the losses had not

been incurred. Increased supplies generally

decrease prices sufficiently so that total farm

income from a large crop may be smaller than

from a small one, unless demand for the product increases simultaneously. The losses given

must, therefore, be interpreted as losses to the

public rather than to farmers.
Chapter 2.-D¡seases of Crop and Ornamental Plants

Plant diseases are commonly defined by plant

pathologists as deviations from normal growth

or structure of the plants. Diseases may be due

to pathogens or parasites (fungi, bacteria,

viruses, nematodes,^ and higher plants) or to

nonparasitic causes (weather, nutritional deficiencies or excesses, and toxic substances including air pollutants).

The interrelation of weather, diseases, insects, and nematodes in causing plant losses

makes it difficult to assign losses accurately to

one cause or the other. For example, the poor

growth associated with yellowing of the leaves

of barley and other cereals was formerly believed to be due to excessive soil water, drought,

storage of nitrogen, or low-temperature injury.

Now barley yellow dwarf virus, transmitted by

several species of aphids, is known to be responsible for much of this type of damage. The

virus overseasons on certain perennial grasses

and volunteer and fall-planted cereal plants.

The severity of the outbreak the next crop

season depends on the size of the population of

infectious aphids, which in turn depends largely

on winter weather.

Some pathogens are disseminated by wind

and rain, and for entry need moisture on the

plant. Certain root diseases occur only when

soil moisture is abnormally high. Weeds may

provide conditions favorable for high relative

humidity in the microclimate about the plant

and thus aid in the development of such diseases

as late blight of tomato and potato.

Diseases may affect any part of a plant

(roots, stems, leaves, flowers, fruit) at any

stage in its development (seed, seedling, mature plant). Diseases reduce yields (from 2

percent in tung to 52 percent in lupines) and

also quahty of certain crops. Diseased grains

may be lightweight, discolored, and shriveled.

Disease-induced poor coloration, blemishes, or

rots of fruits and vegetable crops reduce their

grade. Most consumers are familiar with the

browning and internal discoloration found frequently in lettuce, potatoes, and sweetpotatoes.

The oil content of peanuts, safílower, and soybeans may be lowered by diseases in the crop

plants. Viruses may cause undesirable mottling

of blossoms such as gladiolus and tulip. City

1 Loss estimates for diseases transmitted by insects

are included in this chapter instead of chapter 4.

2 See chapter 3.

dwellers have seen elms and oaks gradually

disappear because of Dutch elm disease, phloem

necrosis, and oak wilt.

Diseases prevent growing of certain crops in

many sections. For example, tomatoes are not

grown in many areas of the West because they

become infected by an insect-transmitted virus

that causes curly top. The bacterial disease

fireblight prevents successful growing of highquality pears in Eastern United States. Most

seed crops are now produced in the arid West

to avoid losses from diseases favored by rains

during the growing season. Mint production

has been moved from one area to another to

avoid damage from verticillium wilt, caused by

a fungus in the soil.

Diseases affect dependability of yield.

Disease losses in a particular crop vary greatly

from year to year, as illustrated by the losses

caused by cereal rusts. Outbreaks of these

diseases depend on the supply of rust inoculum

in Southern United States and Mexico, upper

air circulation to move large quantities of

spores great distances, the prevailing weather,

stage of plant development when the spores

are deposited, and finally resistance to the races

of rust prevalent in any season. In 1935, losses

from stem rust were estimated at 100 million

bushels of spring wheat worth approximately

50 million dollars, and there was another epidemic in 1937. Another serious one, however,

did not occur until the 1950's when race 15B of

stem rust first became prevalent. Because of

severity of damage by this race, 75 percent of

the durum and 25 percent of the hard red

spring wheat acreage was lost in 1953 and 1954.

Certain diseases of plants can produce illness

and death of persons and animals that eat

affected products. In humid areas scabby grain

may be toxic to hogs. The sclerotia of the ergotproducing fungus, which attacks the flowers of

cereals and grasses, contain alkaloids that can

produce convulsions and even kill animals and

human beings. Ergot, however, can be beneficial for it has medicinal use, particularly in

childbirth.

Disease losses affect not only the farmer but

also the consumer. When diseases limit production and result in a short crop, prices usually

increase. Many diseases are effectively controlled at great expense by application of

chemicals. The added cost of production is re-
AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

fleeted in higher prices. Reducing disease losses

not only will enable the farmer to lower his

production costs but will enable him to produce

the food necessary in the future when the

rapidly expanding U.S. population will require

maximum yields on Hmited acreages of cropland.

The^ estimated average annual loss in

potential value caused by plant diseases during

production of crop groups and the cost of

controlling plant diseases are presented in table

TABLE 1.—Estimated average anniml losses in

value caitsed by plant diseases and air pollution to various groups of crops during production and cost of controlling diseases, 1951-

60

Crop group

Average

annual loss

lyOOO dollars

Field crops 1,890,836

Alfalfa and all other hay plants 614,766

Forage seed crops 23,584

Pasture and range plants 193,935

Fruit and nut crops 223,506

Vegetable crops 290,389

Ornamental plants and shade trees 14,099

All crops: Loss from air pollutants 325,000

Total 3,576,114

Cost of controlling diseases 115,800

Grand total 3,691,914

In this chapter losses attributable to pathogens such as bacteria, fungi, and viruses are

emphasized; but occasional estimates of losses

from diseases not caused by pathogens are included. Most of the losses from diseases are

grouped by type of crop: field crops, alfalfa

and all other hay plants, forage plants grown

for seed, pasture and rangeland plants, fruit

and nut crops, vegetable crops, and ornamental

crops and shade trees. Losses are included for

each crop in the various groups. Also included

in this chapter is a section on crop losses caused

by air pollutants.

FIELD CROPS

Estimated disease losses for 23 field crops

for the period 1951-60 appear in table 2. The

average annual losses to field crops caused

by these diseases were estimated to be

$1,890,836,000.

Barley

Annual losses in barley resulting from diseases caused by various plant pathogens during

the period 1951-60 averaged 14 percent. Most

diseases caused about the same reductions in

yield each year.

Several items are not included in the estimated losses from diseases. The area in which

barley is produced in the United States has

moved north and west, partly because corn

hybrids adapted to the areas where barley was

formerly produced have been developed. The

helminthosporium and scab diseases, which

cause little damage to corn, have become so

prevalent and severe on barley in those areas

that it is no longer economical to produce

barley. In some areas of Southern United

States, barley cannot be produced because of

root rots and leaf blights.

Most reduction in production was caused by

two virus diseases: barley stripe mosaic and

barley yellow dwarf. The barley stripe mosaic

virus is transmitted through the seed and by

contact of healthy plants with those harboring

the virus. For many years this disease was referred to as false stripe. It reduced the yield

in many commercial fields by 15 to 20 percent

in the area where malting barley was produced.

Since the quality of the grain was normal and

at harvesttime the disease symptoms were not

evident, growers were not aware of this loss.

The helminthosporium diseases are present

in most areas where barley is grown. They are

most severe in the warmer humid climates.

Fv^arium, or scab fungi, and species of Helminthosporium cause kernel blights that decrease

the quality of malting barley.

The septoria leaf blotch has become very

severe on malting barleys produced in the Red

River Valley of North Dakota and Minnesota.

It has caused only a small reduction in yield

but has resulted in a much higher percentage

of thin kernels. The thin kernels decrease the

value of the crop since they increase the cost

of producing malt.

Loose and other smut fungi cause losses in

most areas where barley is produced.

Estimated average annual losses by specific

barley diseases for the period 1951-60 are as

follows :

Average

annual

. loss

Disease (percent)

Stripe mosaic 3,2

Root rots 2.8

Helminthosporium diseases 2.6

Yellow dwarf ^[g

Fusarium blight, or scab '9

Loose smut [9

Septoria leaf blotch *g

Powdery mildew '5

Rhynchosporium scald '5

Others '2

Total V"SS"_l "TIT"
LOSSES IN AGRICULTURE

TABLE 2.—FIELD CROPS : Estimated average annual losses due to diseases, 1951^60

Commodity Production unit

Loss from potential production i

Reduction 2 Quantity Value

Barley Bushel

Beans, dry Hundredweight.

Castorbeans Pound

Com Bushel

Cotton Bale

Flax (seed) Bushel

Hops Pound

Mint 4 __do

Oats Bushel

Peanuts Pound

Peas, dry HundredweightRice do

Rye Bushel

Safflower Ton

Sesame Pound

Sorghum :

Grain Bushel

Silage and forage 6 Ton

Sweet Gallon

Soybeans Bushel

Sugarbeets Ton

Sugarcane do

Tobacco Pound

Wheat Bushel

TotaL

1,000 1,000

Percent units dollars

14 56,496 55,403

17 3,423 3 24,934

11 3,369 184

12 413,051 527,285

12 1,859 300,920

10 3,757 11,603

13 7,055 3,318

10 406 1,474

21 299,284 198,417

28 499,744 53,716

14 535 2,404

7 3,874 18,799

3 801 928

12 16,345 615

11 5 940 5 121

9 33,866 34,072

9 1,493 8,550

15 463 987

14 64,251 142,835

16 2,420 27,254

23 1,906 13,521

11 243,399 132,203

14 173,911 331,293

1,890,836

1 So far as possible, the basic data used to calculate

the loss in quantity and value represent the averages

for the period 1951-60 as estimated by the Statistical

Reporting Service. Where data were not available, best

approximations were used.

2 Estimate is based on full production with the causes

eliminated. These percentages were applied to the data

of actual farm production to obtain estimates of loss

of farm production in terms of quantity and value.

Loss in quality is included in the loss in value. Value

Beans, dry (¡nclud'mg seed beans, blackeyes, and

dry Umas)

Losses in dry beans and seed beans result

chiefly from root rots caused by several fungi,

including Fusarium, Rhizoctonia, and Sclerotinia. In some years the bacterial blights cause

severe injury in Colorado, Michigan, Nebraska,

and Wyoming. Tv^o virus diseases—New York

15 strain of common mosaic and bean yellow

mosaic—cause considerable damage in some

years, especially in central Washington.

Curly top is found only in States west of the

Continental Divide. The causal virus is transmitted by a single species of leafhopper and it

occurs only where this insect occurs. In some

areas where the vectors are prevalent, such as

southern Idaho, eastern Oregon, and central

Washington, curly top prevents the production

of susceptible varieties.

In southern Idaho, bacterial blights are normally of little consequence and anthracnose

loss is computed upon the assumption that market outlets would be available for reduced production with no

change from average farm prices. See chapter 1 for

more detailed explanation of procedure.

3 Includes blackeyes and garbanzos in California in

addition to ordinary edible beans and beans grown for

seed.

4 Peppermint and spearmint.

5 Basic data are from the 1959 Census of Agriculture.

6 See discussion under sorghum, grain and sweet.

never occurs because of low rainfall. Therefore, much of the seed of dry beans and about

85 percent of all the seed beans used in the

United States are produced here. As a result

of using blight- and anthracnose-free seed,

these diseases have become of minor importance

in the United States.

The average annual increase in disease losses

in the period 1951-60 (17 percent) as contrasted with losses in the previous 10-year

period (11.5 percent) is due to the spread of

sclerotinia wilt and fusarium root rot into new

areas for these diseases. Since 1948-49, losses

from sclerotinia wilt have increased considerably. Beans are now planted 20 or 22 inches

apart in the rows, whereas earlier they were

planted 28 inches apart. Close planting creates

conditions of high relative humidity, which

are ideal for the development and spread of

the causal fungus. This was not the case when

beans were planted 28 inches apart, and losses

from sclerotinia wilt were much less.
AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

Between 1953 and 1960, bean acreage increased considerably in the Columbia Basin of

central Washington, where the soils have very

low humus contents. Bean root-rotting organisms in such soils develop very rapidly because

of lack of competition from nonparasitic organisms that are present in large numbers in

soils with higher humus contents. Losses from

fusarium root rot have increased in this area,

especially in fields where good methods of crop

rotation are not practiced.

Losses in dry lima beans, blackeyes, and

garbanzos are caused chiefly by the root rots

that affect dry and seed beans.

Estimated average annual losses caused by

various bean diseases for the period 1951-60

are as follows :

Average

annual

loss

Disease (percent)

Fusarium root rot 4.5

Sclerotinia wilt 3.5

Bacterial blights 2.0

Rhizoctonia root rot 2.0

Anthracnose 1.0

Bean yellow mosaic 1.0

Common bean mosaic 1.0

Curly top 1.0

Rust 1.0

Total 17.0

Castorheans

The most destructive diseases of castorbeans

are alternaría leaf spot and capsule molds. Each

type of disease causes estimated annual losses

of 5 percent. Alternaria leaf spot was particularly bad on the High Plains of Texas in 1952,

1959, and 1960, when losses were severe. Most

of the acreage in 1961 was planted to resistant

varieties, but losses on the susceptible variety

B296 amounted to 50 percent in some fields.

Capsule molds caused by Alternaria and Botrytis were particularly destructive in 1951 and

1958. Seedling diseases caused average annual

losses of 1 percent. Capsule drop has been particularly bad in experimental plantings in the

humid areas east of Texas. Some varieties in

Mississippi have dropped up to 70 percent of

their capsules before maturity.

Corn

Corn production in the United States is reduced each year by diseases. More than 25 diseases occur to some extent on corn; they attack the plant in various stages of growth.

Leaves, stalks, ears, and roots may be affected.

Not all diseases are found in all of the corngrowing areas.

Many corn diseases appear only sporadically,

but sometimes losses in individual fields may

exceed 30 percent. Generally, losses are due

to lowered grain quality, decreased value of

fodder, and decreased yield. Annual losses in

the period 1951-60 averaged about 12 percent.

Stalk rots comprise the group that causes the

greatest disease losses in corn. The two major

stalk rots are diploida stalk rot, which is most

destructive in the Corn Belt, and gibberella

stalk rot, which is widely distributed but causes

most of its damage in the northern and eastern

parts of the United States. Sometimes associated with stalk rots are ear rots, some of which

are caused by the fungi that attack stalks. Ear

losses also may occur during mechanical harvesting when plants weakened by stalk rots

fall to the ground. Severe epidemics of ear

rots are limited to localized areas and are less

important economically than stalk rots.

Two major leaf diseases of corn are known

as the helminthosporium blights (northern leaf

blight and southern leaf blight). Northern leaf

blight is more widespread and causes more

losses than southern leaf blight. Northern leaf

blight may occasionally become severe locally,

and losses that exceed 30 percent have been

observed in scattered fields when the disease

has become well established 2 or 3 weeks after

silking. It has been increasing in the northern

part of the Corn Belt. Southern leaf blight is

more severe in the Southern States.

Stewart's leaf blight of corn, a bacterial disease, generally appears rather late in the season but can become severe in some years. It

has increased in some areas in the central part

of the United States, especially after mild winters.

Smut causes little damage in corn, although

it is widespread. It is most prevalent in dry

areas ; and when the disease appears in a field

around silking time, it may become severe. The

heaviest damage occurs when ears become infected. In 1956, smut was unusually heavy.

Because of the use of improved hybrids and

high-quality seed treated with fungicides, seedling blights are becoming less destructive.

Sometimes the minor diseases of corn may

become severe in localized areas. Sporadic

epidemics cause the greatest losses.

Estimated average annual losses caused by

specific corn diseases for the period 1951-60

are as follows :

Average

annual

^. loss

Disease (percent)

Stalk rots (fungus) 39

Helminthosporium leaf blights 2 3

Seedling blights -^ß

Root rots ^^'3

Ear rots -^2

Smut 'rj

Bacterial leaf blight \

Physoderma brown spot *2

Others ^'2

Total 12.0
LOSSES IN AGRICULTURE

Cotton

The pattern of cotton disease losses is constantly changing across the Cotton Belt. The

changes are due to differences in environment

from year to year, changed cultural practices,

increased fertilization, and use of excessive

irrigation water. For instance, losses from

verticillium wilt in California are becoming less

severe as the result of use of tolerant varieties.

On the other hand, verticillium wilt is becoming very damaging in western Oklahoma and

the High Plains of Texas, largely because most

of the area is now being irrigated and heavy

applications of nitrogen are used.

During the period 1951-60, annual losses

from all diseases averaged 12 percent. Prevention of these losses would not necessarily increase overall cotton production, but it would

provide an opportunity for improving the lot

of cotton farmers by increasing efficiency of

production with a correspondingly greater return per unit produced.

Seedling diseases are caused by a complex

of seedborne and soilborne organisms. Losses

occur across the entire Cotton Belt but are

greatest in the Southeast where, on the average, seed quality is rather low. Research has

shown that low-quality planting seed is affected

more by adverse conditions after planting than

is high-quality seed, and it is also more susceptible to the seedling disease complex. Seedling

diseases still account for about 20 percent of

the annual disease losses in cotton. The cost

of replanting represents only a fraction of the

potential losses inasmuch as replanted cotton

may be severely damaged by insects and by

weed competition.

Wilts cause more than 25 percent of the

annual disease losses in cotton even though

i^i^sarmm-resistant varieties are available and

control practices that reduce damage by Verticillium are known.

Boll rots are caused by a complex of organisms, many of which are considered to be saprophytes ; but under appropriate conditions, many

of these grow on the uninjured bolls and seriously damage the fiber. The upward trend in

losses from boll rots has been due largely to

attempts to grow greater and greater amounts

of cotton on the same acreage. To do this,

farmers overwatered and overfertilized the

plants, and the plant growth pattern was conducive to boll rots. These practices also contribute to low seed and fiber qualities.

Estimated average annual losses caused by

various cotton diseases for the period 1951-60

are as follows :

Average

annual

r. . l088

Disease (percent)

Seedling diseases 2.6

Verticillium wilt ^ ¿^

Boll rots 2.2

Bacterial blight 1*7

Fusarium wilt i\i

Phymatotrichum root rot [9

Ascochyta blight [2

Others I*Q

Total 12.0

Flax (seed)

Pasmo, rust, and wilt are the most destructive flax diseases in the United States. In 1955-

56 curly top caused losses of 10 to 30 percent

in the Imperial Valley of California and in

Texas. In 1957 losses from aster yellows were

estimated at 20 percent of the crop inthe

Dakotas and Minnesota. Crinkle occasionallycauses small losses. Seedling blight is widely

distributed and causes appreciable loss of stand

in isolated fields nearly every year.

Pasmo is estimated to cause a 3-percent annual loss in yield of flax. This disease occurs

in years of frequent rains and heavy dews

during the period from flowering to maturity.

Varieties diifer in their field tolerance to the

disease. Early-maturing varieties tend to escape with less damage than late-maturing ones.

There were no serious epiphytotics of pasmo

in the period covered by this report.

A new race of flax rust attacked the variety

Dakota in Minnesota and in the Dakotas in

1950-51. Resistant varieties were quickly substituted, and losses were held to 10 percent in

1951, 5 percent in 1952, and 0 to 1 percent in

subsequent years.

Losses from wilt during the period 1951-60

were estimated at 1 percent. All commercial

varieties in Minnesota and in the Dakotas have

a high degree of resistance. A wilt-resistant

variety. New River, released in California, reduced losses in that area to 5 percent.

A number of soilborne and seedborne fungi

occasionally causé seedling blights with resulting stand decimation.

Estimated average annual losses caused by

specific flax diseases for the period 1951-60 are

as follows :

Average

annual

loss

Disease (percent)

Pasmo 3.0

Rust 2.0

Crinkle and aster yellows 2.0

Seedling blights 1.5

Wilt 1.0

Curly top .5

Total 10.0
8 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

Hops

Virus diseases cause the most serious losses

in hop yields (10 percent) in California, Idaho,

Oregon, and Washington. Usually there is a

reduction in yield during the last year or two

the diseased hill remains in the yard, and there

is a further reduction while a new cutting is

being established.

Downy mildew, the most damaging and widespread fungus disease of hops in the United

States, caused an estimated 3-percent reduction in average annual yield during the period

1951-60.

While verticillium wilt is not now a serious

hazard of hops in the United States, a few infected plants have been found, and it may become more destructive in the future.

Mint

Verticillium wilt, which attacks both peppermint and spearmint, caused estimated annual

losses in yield of 10 percent in Indiana and

Michigan during the period 1951-60. It has

been increasing in Oregon and Washington

and caused estimated average annual losses in

yield of 6 percent for 1951-60. The average

annual losses for the entire mint-growing area

are estimated at 8 percent.

Rust causes losses in yield in Oregon and

Washington estimated at 4 percent annually.

The estimated annual losses for the entire mintgrowing area average 2 percent.

Oafs

Oat diseases are a major factor in oat production. In the United States, losses caused by

diseases are generally higher in oats than in

other small grains, because most of the oat

crop is spring grown in warm, humid regions

usually favorable for disease development.

Heavy losses are also experienced in the Deep

South, where oats are fall sown and winters

are mild and humid. However, only about half

of the more than 30 diseases attacking oats in

the United States have caused appreciable damage. Total losses from all diseases during the

period 1951-60 were estimated at 21 percent.

Losses from crown rust averaged 3.7 percent

for 1951-60. Resistant varieties constitute the

only effective control of crown rust, and this

protection is often nullified by the frequent

appearance of new, virulent races of rust. In

1953, crown rust caused estimated losses of

30 percent in Iowa and losses totaling more

than 100 million dollars in the three leading

oat-producing States, Iowa, Minnesota, and

Wisconsin.

Yellow dwarf (virus) caused average annual

losses of 3.8 percent during the period 1951-

60 and superseded crown rust as the most damaging oat disease. The disease is widely distributed and is of major importance throughout

the principal oat-producing regions. Yellow

dwarf symptoms on oats were not fully recognized until about 1956. Previously, much of the

damage caused by yellow dwarf was attributed

to blast, drought, heat, cold, and low fertility.

In 1959 an epiphytotic of yellow dwarf caused

severe damage in the heavy oat-producing

North Central States, with carefully estimated

losses as follows : Missouri, 37 percent; Indiana,

27.5 percent; Kansas, 25 percent; Iowa, 12 percent ; and Wisconsin, 5 percent. The estimated

losses from yellow dwarf in Oregon were 9.1

percent in 1957, 9.5 percent in 1958, and 14.8

percent in 1959. Severe damage also occurred

in the Northeast in 1960.

Some of the 2.5-percent loss from blast reported during 1951-60 possibly should have

been attributed to yellow dwarf, because blasting was not fully recognized as a symptom of

yellow dwarf until about 1956. Blast and root

necrosis, which ranked third and fourth in destructiveness in 1951-60, have several causes

and it is difficult to arrive at accurate loss estimates. The estimates of losses for root necrosis

were based to some extent on yield increases

obtained from soil sterilization and seed treatment.

Stem rust of oats usually has been less severe

than crown rust in the United States, partly

because of the availability of new varieties resistant to stem rust. But a changing stem rust

situation has tended to nullify the protection

afforded by resistant varieties. The threat from

new and more virulent races and subraces could

result in greater losses from stem rust.

Septoria foliage blight, the sixth-ranking oat

disease, caused estimated losses of 15 percent

in the Iowa oat crop in 1952. It affects yield

and quality of both grain and forage. Heavy

infection by Septoria has been most frequently

observed in the Northern States.

The estimated losses in yield of oats from

Victoria blight (Helminthosporium) averaged

only 0.4 percent for 1951-60. This disease

caused severe losses throughout both the northern and the southern oat-producing regions in

1946,1947, and 1948, with Iowa reporting losses

of 25 percent in 1946 and 32 percent in 1947.

A dramatic shift to resistant varieties has virtually eliminated Victoria blight.

Oat smuts, once major diseases, are now of

relatively minor economic importance because

of the widespread use of resistant varieties.

Soilborne mosaic, a virus disease of winter

oats, appears to be increasing in prevalence and

severity.

Losses caused by scab, helminthosporium leaf

blotch, helminthosporium culm rot, bacterial
LOSSES IN AGRICULTURE

diseases, blue dwarf, and nonparasitic diseases

have been relatively minor nationally, although

sometimes they are locally severe.

Estimated average annual losses caused by

specific oat diseases for the period 1951-60 are

as follows : Average

animal

loss

Disease (percent)

Yellow dwarf 3.8

Crown rust 3.7

Blast (sterility) 2.5

Root necrosis 2.4

Stem rust 2.3

Septoria foliage blight 1.8

Scab .9

Helminthosporium leaf blotch .7

Smuts .6

Soilborne mosaic .5

Bacterial stripe blight .4

Victoria blight .4

Blue dwarf .3

Halo blight .3

Helminthosporium culm rot .2

Physiologic leaf spot .1

Others .1

Total 21.0

PeanuH

Principal losses from diseases in the production of peanuts are caused by cercospora leaf

spot and stem rot, or southern blight. Pod rots

not associated with stem rot are of major economic importance in the Virginia-Carolina

area. Root rots, which may be associated with

the stem rot complex, are of concern in Georgia

and Texas.

Estimated average annual losses caused by

various peanut diseases for the period 1951-60

are as follows : Average

annual

loss

Disease (percent)

Leaf spot 10.0

Stem rot, or southern blight 7.5

Pod rots 2.5

Root rots 2.5

Seedling death or stunting 2.5

Seed decay after planting 2.0

Collar and crown rot 1.0

Total 28.0

Peas, dry ('including seed peas)

Losses from diseases of dry and seed peas are

due principally to root rots caused by several

organisms. With the increase in acreage in the

Columbia Basin, where root rots are severe

because of the low humus content of the soils,

these diseases are increasing in importance.

Less severe losses are caused by mosaics, ascochyta and bacterial blights, and powdery

mildew.

Estimated average annual losses caused by

various diseases of dry peas for the period

1951-60 are as follows :

Average

annual

Disease . ^«« ,, Ü 4. X (percent) Root rots r.r.

Virus diseases ~ SR

Ascochyta blight ~ f ^

Fusarium wilts |'}|

Powdery mildew I'A

Bacterial blight 1111111 5

Total ~--:::::"ï4!ô~

Rf'ce

Rice is grown in Arkansas, California,

Louisiana, Mississippi, Missouri, and Texas.

Diseases cause appreciable losses only in the

South. In California, the only major disease

of rice is sterility, which is caused by unfavorable environmental conditions. Because estimates of losses are based on the entire production, losses are somewhat higher in the South

than indicated in the tabulation.

Blast, the most economically important disease of rice, causes major losses in most varieties. Increased use of nitrogen fertilizer, which

favors disease development, and the appearance

of a number of races of the causal fungus have

increased losses during recent years. Kernel

smut, a major disease in some areas in certain

years, sometimes causes severe losses in both

yield and quality. Seedling blight and root rots

also are major diseases of rice. Kernel spots,

caused by several fungi, cause losses in yield

and in quality.

Straighthead, a physiological disease, and

sterility (spikelet or panicle blight) due to unfavorable environmental factors cause appreciable losses each year. The estimated combined losses from these causes is about 2 percent each year. Stem rot occasionally causes

losses, but this disease is becoming less severe.

Fungi that attack the leaf and sheath are prevalent each year in the South. The estimated

combined losses from these diseases average

about 0.6 percent a year.

Estimated average annual losses caused by

specific rice diseases for the period 1951-60

are as follows : Average

annual

loss

Disease (percent)

Blast 1.6

Root rots 1.0

Kernel smut «5

Seedling blight .5

Kernel spots .3

Brown leaf spot .2

Narrow brown leaf spot .2

Stem rot «2

Straighthead .2

Bordered sheath spot .1

Leaf smut .1

Others (sterility and miscellaneous

minor diseases) 2.1

Total 7.0
10 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

Rye

Losses in the potential rye crop in the United

States from all diseases for the period 1951-60

are estimated at 3 percent, somewhat lower

than the estimate for other cereal crops. Losses

are greatest (over 5 percent) in the humid

areas of the Southeast, where rye is grown for

pasture cover or green manure.

Rusts are the principal diseases of rye in all

rye-growing areas and are estimated to cause

losses of about 1 percent. Rust-induced losses

occur in both grain and forage. Various leaf

diseases associated with the fungi Heminthosporium, Septoria, and Rhynchosporium also

are destructive in the Southeast.

Ergot causes losses of about 0.7 percent ; root

rots, about 0.7 percent; and anthracnose, about

0.4 percent. Stalk smut is present in only trace

amounts, but occasionally it may be locally

severe.

Estimated average annual losses caused by

the major diseases of rye for the period 1951-

60 are as follows :

Average

annual

loss

(percent)

1.0

.7

.7

.4

.1

.1

3.0

Disease

Rusts

Ergot

Root rots

Anthracnose

Leaf spots

Stalk smut

Total

Safflower

Rust may be a particularly destructive disease of safïïower grown on irrigated or subirrigated land in central California where humidity

is high. Losses in this area have been as high

as 25 percent. Annual losses for the entire

safflower area during the period 1951-60 averaged about 5 percent.

Root rot may be destructive wherever the

crop is grown on irrigated land. Average annual losses were estimated at 3 percent for the

period of 1951-60.

When the weather is humid, bud rot may be

a serious disease of safflower from flowering

to maturity. Losses may be large, especially

where the crop is grown out of its area of

adaptation.

Verticillium wilt causes small losses wherever safflower is grown.

Estimated average annual losses caused by

specific safflower diseases for the period 1951-

60 are as follows :

Average

annual

loss

Disease (percent)

Rust 5.0

Root rot 3.0

Bud rot 2.0

Leaf spot 1.0

Verticillium wilt .5

Damping-off .3

Curly top .2

Total 12.0

Sesame

Sesame is grown chiefly on the High Plains

of Texas. Bacterial leaf spot of sesame caused

annual losses estimated at more than 5 percent

during the period 1951-60. High nitrogen fertilization, together with periods of cloudy

weather with high humidity, tends to increase

the disease.

Rhizoctonia root rot is responsible for some

loss of stand in almost every field, and the estimated loss of 2 percent for 1951-60 seems

conservative.

Charcoal rot caused additional estimated

annual losses of 2.5 percent. This disease attacks a number of other crops grown in the

area where sesame is grown. Miscellaneous

diseases caused losses of about 1.5 percent.

Sorghum, grain

Reduction in yield of grain sorghum as a result of diseases was estimated at 9 percent for

the period 1951-60. Losses were heaviest in

the southern sorghum-producing areas of the

Plains States, where the major diseases are

stalk rots and head smut. In the higher rainfall

area of Eastern United States, various leaf

diseases cause losses in grain sorghum production. Losses from diseases are lowest in the

Northern Great Plains, Arizona, and California.

Stalk and root rots reduced yields by an estimated 4.5 percent during the period 1951-60.

These diseases are typically sporadic and,

therefore, it is diflicult to arrive at average

losses. Charcoal rot is the most destructive and

may cause total loss in small areas, such as a

160-acre field, or in areas the size of a county

or several counties. It occurs with greatest

regularity in the Southern Great Plains.

The loose and covered kernel smuts of grain

sorghum, once destructive diseases, are now

controlled effectively by seed treatment. In

contrast, head smut has increased markedly

m recent years and is estimated to cause a loss

of 1 percent. It may cause losses as high as

30 percent m south and central Texas and as

high as 10 percent in irrigated sorghum in

western Kansas.

During 1951-60, seed rots and seedling diseases caused estimated losses of 1 percent
LOSSES IN AGRICULTURE

11

These diseases are more severe in cool, wet

springs in the more northern areas when the

seed is planted early. Some of the loss would

be represented in the cost of 2 to 3 pounds per

acre of additional seed sown in anticipation of

loss in stand from diseases. With the shift to

hybrid sorghums, some reduction in losses may

be expected, since virtually all hybrid seed is

treated with fungicides.

Leaf diseases such as helminthosporium leaf

blight, bacterial blights, and rust may cause

losses in the eastern and southern portions of

the grain sorghum area. Anthracnose is also

destructive, particularly in the Southeast. However, in the major grain sorghum-producing

areas, these diseases cause so little damage that

losses do not exceed 2 percent of the grain

sorghum crop as a whole.

Estimated average annual losses caused by

various diseases of grain sorghum for the period 1951-60 are as follows :

Average

annual

loss

Disease (percent)

Charcoal rot and other stalk and root rots 4.5

Head smut 1,0

Seed rots and seedling diseases 1.0

Bacterial blights .3

Helminthosporium leaf blight .2

Weak neck .2

Anthracnose ]l

Loose and covered kernel smuts !l

Others (miscellaneous leaf diseases, rust, etc.) 1.6

Total 9^0

Sorghum, sweet

Losses in sweet sorghum in the Southeast

during the period 1951-60 were caused primarily by four fungus diseases : gray leaf spot,

zonate leaf spot, rust, and red rot including

leaf anthracnose. Gray leaf spot was a deAlabama, Louisiana, Mississippi, and Tennesstructive disease of susceptible varieties in

see. Zonate leaf spot was prevalent most seasons on highly susceptible varieties in Tennessee. Rust is a serious disease annually on

susceptible varieties in humid areas of Louisiana, Mississippi, and other Southern States.

Losses from red rot including leaf anthracnose

were reduced in the 1950's by the use of resistant varieties ; it occurs on susceptible varieties in all sirup-producing States.

Bacterial stripe occurs on susceptible varieties of sweet sorghum in sirup-producing areas

of the Southern States; losses are usually

minor. The virus that causes mosaic of sugarcane damages sweet sorghum in Alabama,

Georgia, Louisana, and Mississippi when the

crops are grown in close proximity. Other

fungus diseases that cause minor losses in

sirup-producing areas of the South are sooty

kSFhien^^ blight, smut, rough spot, and pokDisease losses in sweet sorghum occur re^ularly They reduce growth and sugar content

of the sorghum and the total yield of sirun

Losses from all diseases reduced the total anl

nual yield an estimated 15 percent during thp

period 1951-60. ^

Estimated average annual losses caused by

various diseases of sweet sorghum for the period 1951-60 are as follows:

Average

annual

^. loss

Visease (percent)

Gray leaf spot 2.8

Zonate leaf spot 2*7

Rust 1*2

Red rot including leaf anthracnose 1.1

Others 7*2

Total 1.17"_. lö'.O

Soybeans

Most of the disease losses in soybeans in the

United States are caused by 12 diseases, but

more than twice this number are known to

attack the crop. Some newly discovered bacterial diseases apparently cause damage, but

they are not well enough understood to be included in the estimates.

Use of varieties resistant to the destructive

foliage disease bacterial pustule reduced losses

from this disease in the southern half of the

soybean-producing area during the period

1951-60, but no variety resistant to this disease and adapted to the northern production

area was available.

Varieties resistant to frogeye leaf spot reduced losses from this disease, particularly in

the south-central part of the soybean-producing

area, where losses from it were most severe.

However, a new race of the frogeye fungus

has become prevalent in areas where frogeye

was previously a serious problem.

The leaf disease bacterial blight is prevalent

throughout the soybean-producing area in the

United States, and most varieties are susceptible to it. The complex inheritance of resistance

to the disease and the different races of the

causal organism make the development of resistant varieties difficult.

The leaf disease downy mildew, the most

widespread soybean disease in the United

States, is prevalent throughout the soybeanproducing area. Many races of the causal

fungus are known, and no commercial variety

is resistant to all of them. However, selection

of improved varieties for resistance to some

races and low susceptibility to others has kept

losses from this disease at a moderate level.
12 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

The most destructive fungus disease of soybeans is phytophthora root and stem rot, one

of the few soybean diseases that has caused

total losses. The causal fungus is widespread

throughout the soybean-producing area of the

country, except in the extreme northern part

and in the light, well-drained soils in the southern part. Damage from the disease ranges from

stunting of the plants to death. Most southern

varieties are tolerant or resistant to the disease.

Two diseases of soybeans, pod and stem

blight and purple stain, reduce seed quality

much more than they reduce yield. Both diseases are prevalent in the soybean-producing

areas of the United States, but losses from them

are most severe in the humid areas of the East

Coast and the South.

Stem canker, a widespread disease throughout the northern half of the soybean-producing

area, causes death of plants late in the growing

season. No varieties resistant to the disease

are known, but selection of varieties with a low

incidence of the disease has helped to keep losses

at a minimum.

Brown stem rot is widespread throughout the

soybean-producing areas but is particularly

severe where soybeans are grown continuously

or rotated infrequently with nonsusceptible

crops. No completely resistant variety is known,

but some varieties are much more severely affected by the disease than are others.

Soybeans are affected by a number of viruses ;

the main one is the tobacco ringspot virus,

which causes bud blight and is prevalent

throughout the soybean-producing areas. Although this disease sometimes causes complete

loss of yield, it occurs sporadically from year

to year. Since symptoms are difficult to recognize except in the most extreme stages, losses

from it might be substantially underestimated.

Estimated average annual losses caused by

specific soybean diseases for the period 1951-

60 are as follows :

Average

annual

loss

Disease (percent)

Phytophthora rot 2.3

Bacterial blight 2.2

Downy mildew 1«6

Bacterial pustule 1.4

Pod and stem blight 1.2

Stem canker 1.1

Bud blight .8

Brown spot .8

Brown stem rot .8

Purple stain .7

Fusarium root rot .6

Frogeye leaf spot .1

Others .4

Total 14.0

Sugarbeeis

Diseases are serious hazards to stable production of sugarbeets and cause losses in all

areas. In California and the Pacific Northwest,

beet yellows and western yellows reached epidemic proportions during the period 1951-60.

Curly top is responsible for losses in the sugarbeet areas west of the Rocky Mountains.

In the sugarbeet areas east of the Rocky

Mountains, cercospora leaf spot and black root,

both fungus diseases, reduce yield and quality.

Minor diseases such as downy mildew and

rust occur in California, where they reduce

yields significantly some years. Mosaic is most

prevalent in California and in the Pacific

Northwest, and savoy is found in the Great

Lakes area.

Rhizoctonia and other root rots are responsible for severe loss of mature roots before

harvest. These losses fluctuate with weather

conditions and cropping practices.

Estimated average annual losses caused by

various sugarbeet diseases for the period 1951-

60 are as follows : Average

annual

loss

Disease (percent)

Yellows (beet yellows and western yellows) 6.0

Cercospora leaf spot 3.0

Curly top 3.0

Root rots 2.0

Black root 1.0

Minor diseases (downy mildew, rust, diseases

caused by Phoma, savoy, and mosaic) 1.0

Total 16.0

Sugarcane

Sugarcane diseases regularly decrease growth

of the crop and reduce the sucrose content and

yield of sugar. The ratoon stunting disease,

caused by a virus, is the most damaging disease

in Florida, Louisiana, and the sirup-producing

States (Alabama, Georgia and Mississippi).

Mosaic, another virus disease, is prevalent in

all U.S. mainland sugarcane-producing areas;

losses from mosaic have been reduced by the

use of resistant varieties.

Diseases caused by soil pathogens reduce

yields of sugar in Hawaii and in most sugarcane-producing areas of the mainland.

Red rot, a fungus disease, causes severe losses

in stands and total yield of sugar and sirup

in Florida, Louisiana, and the sirup-producing

States. Rind disease is prevalent in Hawaii,

but it is of minor importance in other areas!

Other fungus diseases that cause some losses

in mainland sugarcane-producing areas are

pythium root rot, phytophthora rot, pokkah

boeng, and red stripe.

Estimated average annual losses by various

sugarcane diseases for the period 1951-60 are

as follows :
LOSSES IN AGRICULTURE 13

Average

annual

loss

Disease (percent)

Ratoon stunting disease 13.7

Red rot 4.5

Diseases caused by soil pathogens 1.7

Mosaic .8

Pokkah boeng .8

Rind disease .7

Pythium root rot .5

Red stripe ,2

Phytophthora rot ,i

Total 23.0

Tobocco

In the period 1951-60, estimated disease

losses in tobacco were 11 percent. During that

period losses were sharply reduced primarily

by the development and increased use of

disease-resistant varieties. Development of

burley varieties with resistance to wildfire and

mosaic greatly reduced losses from these diseases. More recently, cigar tobaccos with resistance to wildfire and tobacco mosaic have

become available. Varieties of various types

of tobacco resistant to one or more stalk diseases such as blank shank, Granville wilt, and

fusarium wilt have been developed.

Severe losses to the growing tobacco crop

are caused primarily by four classes of diseases: root rots, leaf spots, virus diseases,

and stalk diseases. Losses during curing may

be severe, especially in air-cured tobacco.

Root rots reduce plant growth in all tobaccogrowing areas. Black root rot is especially

damaging in the burley and cigar tobaccoproducing areas. Leaf spots reduce yields and

in some instances affect quality. Virus diseases

are prevalent in all areas. They always reduce

yields and quality of cured leaf.

Though black shank appears to be more widespread than formerly, the severity of the disease in general is being controlled more effectively by use of resistant varieties and crop

rotation. Many varieties resistant to black

shank are also resistant to other stalk and root

diseases.

Blue mold commonly occurs in seedbeds each

year. It causes shortage of transplants, delay

in planting, and resultant poor stands. Blue

mold is sometimes a serious problem in field

plantings of cigar-wrapper tobacco.

Miscellaneous tobacco diseases occasionally

cause some damage. These include sore shin,

southern stem rot, and damping-off of transplants. Cercospora leaf spot causes considerable damage to burley and Maryland tobaccos.

Losses from brown spot have increased on ñuecured tobacco. Losses from air pollution (see

discussion of this subject) have been recognized

in cigar-wrapper tobacco.

Estimated average annual losses caused by

various tobacco diseases for the period 1951-.

60 are as follows :

Average

annual

^. loss

Disease (percent)

Leaf decay during curing 2.7

Tobacco mosaic 1.4

Wildfire I'.s

Miscellaneous stalk and root diseases l!i

Black shank 1.0

Black root rot '9

Brown spot 'g

Blue mold ,Q

Blackfire [3

Miscellaneous leaf diseases .3

Frogeye ,2

Fusarium wilt .2

Granville wilt .2

Total 11.0

Wheat

Diseases continue to be a major hazard in

wheat production in the United States and

cause losses principally through reducing yield

and quality of grain. Estimated annual losses

from all diseases for the period 1951-60 were

14 percent. Losses were due principally to a

series of epidemics, including stem rust epidemics in the spring wheat areas in the early

1950's; wheat streak mosaic outbreaks in the

hard red winter wheat areas, especially in 1954

and 1959; epidemics caused by Septoria, principally in the eastern soft winter wheat area

during several years in the decade; and the

common bunt and stripe rust epidemics, which

reduced the wheat crop in the Pacific Northwest.

The most destructive diseases of wheat are

rusts. Stem rust caused the heaviest losses,

principally due to the ravages of race 15B,

which devastated the hard spring and durum

regions and caused an average annual loss of

over 11 percent. Losses from stem rust in 1953

and again in 1954 were estimated at more than

200 miUion dollars. Losses in 1952 and 1953

were estimated to be between 10 and 50 million

dollars and in 1956 and 1957, between 5 and

10 million dollars.

Leaf rust is estimated to have resulted in

losses of 2.5 percent. Normally, leaf rust does

not cause outright crop failures such as associated with stem rust, but it is present every

year in most areas where wheat is grown.

Stripe rust appeared for the first time in the

Plains States and was epidemic in the Pacific

Northwest in 1960 where it reduced wheat

production an estimated 15 to 25 percent.

Virus diseases caused losses of nearly 2 percent during the decade. The chief offender was

wheat streak mosaic, with an average annual

loss of 1 percent. Epidemics of wheat streak
14 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

mosaic occurred in 1953, 1594, and 1959. It

is estimated, for example, to have reduced

yields 20 percent in Kansas in 1959. Soilborne

mosaics caused estimated losses of 0.5 percent.

Experimental evidence that barley yellow

dwarf may damage wheat severely is accumulating but, because of the obscurity of the symptoms, estimates of losses were not made.

Septoria leaf and glume blotch was particularly destructive in the midwestern and eastern

soft wheat areas. Estimates of losses ranged

up to 7 percent in these areas. On a national

basis this disease reduced potential yield by

1 percent. Powdery mildew (0.4-percent loss)

caused small but consistent losses in these areas.

Scab, which is most severe in the eastern and

southern soft wheat areas, caused estimated

losses of 2 percent in Kansas alone.

Root rots, foot rots, and seedling blights are

known to take a heavy toll of the national wheat

production potential, but reliable estimates of

damage are difficult to obtain. Conservative

estimates place these losses at about 2 percent.

These diseases appear to be increasing in destructiveness as wheat culture becomes more

intensive with larger rates of fertilizer being

applied and, in many cases, with less crop rotation being practiced. Snow molds (0.1-percent

loss) associated with Fusarium or Typhula take

an annual toll throughout the most northern

winter wheat areas, and frequently they are

locally severe enough to cause crop failure,

particularly in the Pacific Northwest and Intermountain areas.

National losses from the various smut (bunt)

diseases were in excess of 1 percent during

the period 1951-60. Common bunt, which was

epidemic in the Pacific Northwest during most

of the decade, reduced both the yield and quality

of the crop. Introduction of more efficient seedtreatment fungicides and resistant varieties resulted in nearly complete control of this disease. At the same time, dwarf bunt continued

to cause ever greater losses over a wider area,

particularly in the winter wheat areas of the

Pacific Northwest. Loose smut causes losses

in the eastern soft winter wheat areas and the

eastern parts of the hard red winter wheat

and hard red spring wheat areas. Losses are

rather consistent from year to year and from

decade to decade.

Estimated average annual losses caused by

various wheat diseases for the period 1951-60

are as follows :

Average

annual

loss

Disease (percent)

Stem rust 4.0

Leaf rust 2.5

Root rots 1-Ö

Average

annual

loss

Disease (percent)

Septoria leaf and glume blotch 1-0

Wheat streak mosaic ^-^

Loose smut -^

Cercosporella foot rot -^

Scab -5

Soilborne mosaics «^

Common bunt A

Powdery mildew A

Take-all .2

Bacterial diseases .1

Dwarf bunt .1

Miscellaneous leaf and head blights .1

Miscellaneous virus diseases .1

Snow molds caused by Fusarium or Typhula,

or both .1

Stripe rust .1

Others .5

Total 14.0

ALFALFA AND ALL OTHER HAY PLANTS

Annual disease losses for hay crops are difficult to assess because losses in perennial

grasses and legumes usually are cumulative.

Foliar blights and root rots take their toll of

plants and affect productivity of a hay crop as

long as the stand is retained. Infections by

crown and root rot fungi and viruses are not

always immediately fatal. These pathogens

frequently weaken plants so that they are unable to withstand adverse conditions such as

summer drought and low winter temperature.

Defoliation by leaf spot fungi reduces not only

the yield of hay but also its quality, since a

higher proportion of stems than leaves is

harvested.

In the decade 1951-60, control measures were

developed for diseases of some forage plants;

however, new disease outbreaks occurred on

others. Widespread use of varieties of alfalfa

resistant to bacterial wilt appreciably reduced

losses attributable to this disease. However, the

recent recognition of Pierce's disease of grapevine, caused by alfalfa dwarf virus, in the Gulf

Coast States and in the Eastern United States

suggests that this virus may be prevalent in

eastern alfalfa fields. During the late 1940's,

the disease appeared more frequently and

became increasingly destructive so that it is

now considered to be one of the major leaf spots

of alfalfa in North-central and Northeastern

United States.

Estimated disease losses to alfalfa and all

other hay plants appear in table 3. The average

annual losses to these crops were estimated to

be $614,766,000.

Estimated average annual losses caused by

various diseases in alfalfa grown for hay for

the period 1951-60 are as follows :
LOSSES IN AGRICULTURE 15

Average

annual

loss

Disease (percent)

Bacterial wilt 5.0

Crown and root rots 5.0

Virus diseases 5.0

Foliar diseases including black stem 9.0

Total 24.0

TABLE 3.—ALFALFA AND ALL OTHER HAY

PLANTS: Estimated average annital losses

due to diseases, 1951-60

ProducCommodity tion

unit

Loss from potential

production!

Reduction 2 Quantity Value

Alfalfa Ton

All other

hay

plants —do

Total__

Percent

24

15

1,000

units

17,562

1,000

dollars

388,648

9,439 3 226,118

614,766

1 See table 2, footnote 1.

2 See table 2, footnote 2.

3 Value computed at $23 per ton.

The numerous pathogens that attack true

clovers and sweetclover cause losses in stand,

yield, and quality of the crop. Root and crown

rots are generally held responsible for making

red clover behave as a biennial rather than a

perennial. In most of the area where red

clover is grown, root and crown rots virtually

destroy stands by midsummer of the second

year.

Estimated average annual losses caused by

various diseases in red clover grown for hay

for the period 1951-60 are as follows :

Average

annual

loss

Disease (percent)

Crown and root rots 23.0

Leaf spots and rust 6.5

Virus diseases 5.5

Total 35.0

In ladino clover, virus infection frequently

builds up so that 50 percent or more of the

plants in some fields are infected by the third

year. Virus infection, coupled with damage

from root and stolon rot fungi, frequently

causes rapid depletion of the legume in pasture

and hay fields. Improved varieties of clovers

are available and are being grown more widely.

Attacks by crown and root rot fungi have

largely eliminated stands of birdsfoot trefoil

in the southernmost area of its adaptation.

Stemphylium leaf spot also is widespread and

may cause extensive defoliation in some years.

Perennial grasses grown for hay are generally attacked throughout the growing season

by a succession of foliar pathogens. Most damage results from premature withering and

drying of leaves, which reduces productivity

and quality of the hay.

FORAGE PLANTS GROWN FOR SEED

Between 850 and 900 million pounds of forage seed valued at 175 to 200 million dollars is

produced annually in the United States ; losses

due to diseases for the period 1951-60 were

estimated at $23,584,000 (table 4).

Most improved varieties of commonly grown

grasses and legumes adapted to the Midwest

and Eastern United States are increased for

seed in the West. Consequently, diseases of

little or no importance where plants are grown

for pasture, hay, or turf may be very destructive on improved varieties grown to maturity

for seed in the West. Outbreaks of rusts on

red clover, some varieties of orchardgrass, and

Kentucky bluegrass have caused losses in seed

production and quality. In 1960, a severe outbreak of stripe rust in Merion Kentucky bluegrass seed fields in western Oregon threatened

production of seed of this grass until effective

fungicide treatments were developed. Blind

seed disease of perennial ryegrass sometimes

recurs alarmingly when the price of seed drops

and growers attempt to economize by discontinuing recommended control measures. Usually ergot does not seriously limit seed production by most grass species; however, it is

omnipresent on dallisgrass in the South and is

considered to be the major factor limiting commercial production of dallisgrass seed in the

United States.

Virus infections in clovers, alfalfa, and other

legumes are more prevalent and severe in the

Pacific Northwest than had been originally

anticipated. Virus infection has reduced seed

production of ladino clover as much as 53 percent.

Seed yields of red and alsike clover fields are

frequently reduced by attacks of crown and

root rot fungi. Sclerotinia crown and stem

rot is a widespread, destructive winter disease

of legumes in the Southeastern States. Frequently, large patches of seedlings and older

plants in crimson clover seed fields are destroyed by Sclerotinia.

During the period 1951-60, acreage of sweet

yellow lupine grown for forage and seed in

Florida dropped from 200,000 acres to less than

1,000, largely because of widespread infection

by seedborne bean yellow mosaic virus.
16 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

TABLE 4.—FORAGE PLANTS GROWN FOR SEED : Estimated average annual losses due to disease,

1951-60

Commodity

Alfalfa PoundBluegrass, Kentucky 3

Brome, smooth

Clover:

Alsike

Crimson

Red

White (including ladino).

Fescue, tall

Grasses:

Miscellaneous 4

Turf 5

Legumes, miscellaneous 6

Lespedeza

Lupines

Orchardgrass

Ryegrass

Sweetclover

Timothy

Trefoil, birdsfoot

_do_

-do_

-do-

-do^

_do_

-do_

_do_

_do_

_do_

_do.

-do_

_do_

-do_

_do_

_do_

Loss from potential production i

Production unit

-_do

-do

TotaL

1 See table 2, footnote 1.

2 See table 2, footnote 2.

3 Includes Merion bluegrass.

4 Includes wheatgrasses, Russian wildrye, bluestems,

gramas, switchgrass, dropseed, buifalograss, rhodesgrass, lovegrass, redtop, reed canarygrass, bermudaReduction 2 Quantity

Percent

9

8

8

20

12

32

24

4

5

12

7

14

52

8

6

8

4

18

1,000

units

17,923

1,749

1,054

2,391

2,490

33,100

3,365

1,365

4,196

1,979

7,019

19,174

15,810

1,056

7,726

3,246

1,620

267

Value

1,000

dollars

4,751

525

126

540

511

9,044

2,053

236

623

607

543

2,134

553

169

505

288

171

205

23,584

grass, bahiagrass, dallisgrass, sudangrass, millets,

johnsongrass, and pangóla.

5 Includes chewings fescue, red fescue, and bentgrass.

6 Includes common vetch, hairy vetch, purple vetch,

and Austrian winter peas.

Estimated average annual losses in seed

production caused by various diseases in five

kinds of forage plants for the period 1951-60

are as follows :

Average

annual

loss

Crop and disease (percent)

Alfalfa:

Virus diseases 3.0

Bacterial wilt 2.0

Black stem and other foliar diseases 2.0

Crown and root rots 2.0

Total 9.0

Clover, crimson:

Crown rot 6.5

Leaf spots 3.0

Virus diseases 2.5

Total 12.0

Clover, red:

Crown and root rots 28.0

Virus diseases 5.5

Leaf spots and rust 3.5

Total 32.0

Clover, white (including ladino) :

Virus diseases 13.0

Crown, root, and stolon rots 10.0

Foliar diseases 1.0

Total 24.0

Average

annual

Crop and disease (percent)

Lupines:

Virus diseases 25.0

Stemphylium leaf spots lö'o

Brown spot 7^0

Anthracnose and root rots 5*0

Total 52.0

PASTURE AND RANGELAND PLANTS

Approximately 50 percent of the total land

area of the United States is used for pastures

or grazing. These grazing lands cover a diversity of soils and climatic conditions, which

influence the type and density of cover, productive capacity, and quality of the forage. The

returns from these grasslands in the form of

animals and animal products depend on the

particular plants or mixtures, their yield and

their resistance to heat, drought, or other

hazards. Accurate data are not available on

the returns from U.S. grazing lands. It has

been estimated, however, that at least half of

all the feed nutrients consumed by domestic

livestock are provided by pastures and range-
LOSSES IN AGRICULTURE

lands. In addition, such lands are of value in

soil and water conservation and the maintenance of land resources.

Pasture and range grasses and legumes

persist under highly competitive and often

very adverse conditions. Consequently, each

species and frequently each plant continuously

competes with its neighbor for existence. Thus,

any hazard or combination of hazards that

exerts stress on desirable forage plants tends

to weaken or eliminate them so that they are

often replaced by less desirable species or

weeds. Plant diseases are one hazard affecting

pasture and rangeland species. Losses from

diseases were estimated at $193,935,000 for the

period 1951-60 (table 5).

More than 75 fungi, bacteria, and viruses

have been identified as the causal agents of

pasture grass and legume diseases. Representatives of these groups of pathogens attack

plants at any stage of development from seed

germination to maturity. Some organisms

such as seedling blight and root rot fungi inhibit seed germination, kill seedlings, or attack

and weaken older plants. Some fungus diseases

such as stripe smut and certain virus infections

cause chronic conditions that weaken plants.

The plants fail to withstand adverse conditions

that ordinarily would not seriously affect their

growth and survival. Fungi inciting leaf spots

often occur sporadically throughout the growing season. Abundant leaf spots cause leaves

to wither and die prematurely. In addition to

weakening plants and reducing their productivity, foliar diseases, when severe, reduce

palatability and nutritive value of the forage.

Fungi inciting head smut and ergot in grasses

reduce natural reseeding on ranges. Furthermore, cattle grazing on ergot-infected grass

heads are sometimes poisoned.

17

Losses from plant diseases in pastures and

rangelands occur more frequently under hunSd

conditions and usually are more severe How

ever plant pathogens attack pasture grassed

and legumes even under arid conditions, where

dew provides sufficient moisture for fungus

spores to germinate and infect plant tissues

Moisture from occasional showers and from

melting snow provides conditions favorable

for development of seed rots, seedling blights

and root rots on range grasses in Western

United States. Losses from disease organisms

m irrigated regions sometimes approach those

m humid regions.

FRUIT AND NUT CROPS

Estimates of losses in fruit and nut crops

due to diseases were restricted to those grown

commercially. Limited acreages for home and

farm plantings and on small estates were not

considered. The average annual losses were

estimated at $223,505,000 for the period 1951-

60 (tablee).

Almonds

Because of their climatic requirements,

almonds are grown commercially only west of

the Rocky Mountains. Plantings are particularly extensive in California.

Two fungus diseases are prevalent in all

almond-growing areas. The first is brown rot,

which is serious on the blossoms because the

fungus can materially reduce the size of the

crop by blighting them. The second disease,

called shot hole or coryneum blight, causes extensive gum production and kills the blossoms,

twigs, and branches.

A noninfectious bud failure has increased

recently enough to cause as much damage as

either brown rot or shot hole, or even more.

TABLE 5.—PASTURE AND RANGELAND PLANTS : Estimated average anmml losses due to diseases,

1951^60

Commodity

Loss from potential production i

Production unit

Reduction 2 Quantity 3 Value

Cropland pastures Acre__.

_ __do__.

_ __do__.

Percent

9

3

5

IfiOO

units

6,387

7,839

33,871

IflOO

dollars

4 76,645

Forest land pastures 5 15,677

Grassland pastures and range

Total

6 101,613

193.935

1 See table 2, footnote 1.

2 See table 2, footnote 2.

3 Basic data on quantities are

Research Service.

from the Economic

4 Computed at $12 per acre.

5 Computed at $2 per acre.

6 Computed at $3 per acre.
18 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

TABLE 6.—FRUIT AND NUT CROPS: Estimated average annual losses due to diseases, 1951-60

Commodity Production unit

Loss from potential production i

Reduction 2 Quantity Value

1,000 1,000

Percent units dollars

9 4 2,521

8 9,612 17,791

7 15 1,782

34 4 11,169 4 1,472

14 5,520 1,842

24 60 12,355

9 107 1,298

4 (5) 122

2 35 1,020

27 959 48,415

25 163 11,137

12 686 38,560

14 9,891 19,805

17 5,589 10,176

21 40,006 9,963

10 9 1,612

10 49 4,895

38 18,445 5,191

26 6 153,517 6 26,869

2 2 109

18 15 6,570

Almonds Ton

Apples BushelApricots Ton

Blackberries 3 QuartBlueberries do

Cherries Ton

Cranberries BarrelFilberts (hazelnuts) Ton_

Grapefruit

Grapes

Lemons

Oranges

Peaches

Pears

Pecans

Plums

Prunes, fresh

Raspberries QuartStrawberries Pound

Tung Ton__.

Walnuts —do__

do

do

__do___

__do___

__do___

BushelPoundTon

—do

Total 223,505

1 See table 2, footnote 1.

2 See table 2, footnote 2.

3 Includes both trailing (dewberries) and erect blackberries.

4 Basic data for quantity and value are from the 1959

Census of Agriculture.

5 Loss in quantity was estimated at about 300 tons.

6 Basic data represent the quantity marketed and its

value.

Estimated average annual losses caused by

various diseases of almonds for the period

1951-60 are as follows :

Average

annual

loss 1

Disease (percent)

Brown rot 2.0

Shot hole 2.0

Crown gall 1.0

Dieback .5

Ring spot (virus) .5

Root rots .5

Verticillium wilt .5

Others, including bud failure 2.0

Total 9.0

1 Based on data from Interior Valleys and some

coastal areas of California.

Apples

Apple scab, a fungus disease, is perhaps the

major disease problem facing apple grov^ers

east of the Rocky Mountains. The causal fungus

is widely distributed and is a threat every year.

It makes the fruit worthless when infection is

heavy, and even scattered infections result in

misshapen, small fruit. Also it invades the

leaves. Scab still accounts for about half of

the total losses.

Fireblight and black rot, which account for

about 25 percent of the total losses, are next

in destructiveness. Other diseases such as apple

blotch, bitter rot, botryosphaeria rot, cedarapple rust, fly speck, and sooty blotch also take

a toll of the fruit in the East. These fungus

diseases occur more sporadically than scab, but

in favorable years they can destroy appreciable

quantities of the crop. Black rot, apple blotch,

and bitter rot cause more damage in the

southern part of the apple belt.

Most apple diseases cause little damage in

the arid fruit-growing sections of the Far

West; powdery mildew, however, is prevalent

and is very difliicult to control, especially on the

Jonathan and Rome Beauty varieties. Both of

these varieties are also very susceptible to fireblight and therefore many farmers do not grow

them.

Estimated average annual losses caused by

specific diseases of apples for the period 1951-

60 are as follows :
LOSSES IN AGRICULTURE

19

Average

annual

loss 1

Disease (percent)

Scab 3.7

Black rot 1.1

Fireblight 1.1

Bitter rot *3

Powdery mildew .2

Virus diseases "_ [2

Apple blotch *1

Armillaria root rot ]l

Botryosphaeria rot 'l

Brook spot 1

Cedar-apple rust 'l

Crown gall \

Ply speck \

Sooty blotch 'l

Others ie

Total 8.0

1 Based on data from California, Delaware, Georgia.

Ilhnois^ Kansas, Maryland, Michigan, New Hampshire,

New York, North Carolina, Ohio, Oklahoma, Oregon

Pennsylvania, Rhode Island, South Carolina, Virginia

Washmgton, and West Virginia.

Aprïcofs

Apricots, like almonds, are grown commercially only in the Far West. Most of the commercial acreage is in California, but large plantings exist also in Washington and Utah.

Two fungus diseases—brown rot and shot

hole (Coryneum)—are universally present in

these western apricot orchards. They are responsible for gum flow and blighting of the

twigs and blossoms, and Coryneum also spots

the leaves and fruit. These diseases, which are

most damaging during the blossom period, represent a constant threat to the industry. Other

diseases such as bacterial canker, powdery

mildew, virus diseases, armillaria root rot, and

crown gall also cause losses.

Estimated average annual losses caused by

various diseases of apricots for the period 1951-

60 are as follows :

Average

annual

lossi

Disease (percent)

Brown rot 1.7

Armillaria root rot 1.0

Virus diseases 1.0

Bacterial canker .9

Powdery mildew .9

Crown gall .5

Shot hole .4

Phytophthora canker .3

Others .3

Total 7.0

1 Based on data from California and Washington.

Blueberríes

Commercial blueberry culture is confined

largely to special areas in Massachusetts,

Michigan, New Jersey, North Carolina anH

Washington. Blueberry plantings are damS

by various diseases; but mummy berry and

stem canker (fungus diseases) and stunt (a

virus disease) are the major commercial problems These three diseases were responsible for

about one-third of the estimated annual losses

reported for the period 1951-60. About onethird was attributed to blossom and twig blight

^,^^^^^^py t^, common gray mold fungus

(Botryhs). The remaining one-third was

caused by a miscellaneous group of diseases.

Mummy berry occurs in all blueberry-growmg areas. The young blossoms are infected,

and the fruit is converted into a hard, inedible

mass as the result of development of the causal

fungus in the inner tissues. Blighting of the

twigs further reduces the size of the crop.

Partial control (about 75 percent) is achieved

by using caustic sprays to kill the fungus on the

ground and by spraying the bushes with fungicides to protect them from infection.

Stunt occurs in Michigan, New Jersey, North

Carolina, and the New England States. Infected plants slowly decline in vigor, become

unproductive, and eventually die.

Stem canker occurs mainly in North

Carolina. The causal fungus girdles the canes

and weakens the plants, which eventually die.

Blossom and twig blight occurs sporadically

and is usually economically important only in

rainy seasons. The causal fungus grows from

the infected blossoms into the shoots and starts

twig blight.

Estimated average annual losses caused by

various diseases of blueberries for the period

1951-60 are as follows :

Average

annual

loss 1

Disease (percent)

Blossom and twig blight 4.4

Stem canker 2.5

Mummy berry 1-3

Stem blight 1-3

Stunt .9

Bacterial cane blight •'^

Powdery mildew -6

Godronia blight -5

Phyllostictina leaf spot -5

Double spot -3

Septoria leaf spot and canker .3

Anthracnose -1

Gloeocercospora leaf spot 1

Leaf rust -1

Mosaic •!

Phomopsis twig blight -1

Ring spot .1

Stem and leaf fleck -1

Total 14.0

1 Based on data from Michigan, New Jersey, North

Carolina, and Washington.
20 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

Bramblebernes (blackberries and raspberries)

In the United States, about one-third of

bramble crops are lost each year to disease.

Virus diseases alone accounted for about onethird of the total estimated losses reported for

the period 1951-60. Fungus-induced rots

caused about one-seventh of the total. Septoria

leaf spots of blackberry is a major problem in

the South.

Estimated average annual losses caused by

various diseases of blackberries and raspberries

for the period 1951-60 are as follows :

Average

annual

loss

Crop and disease (percent)

Blackberries:!

Virus diseases 9.4

Fruit rots 6.2

Anthracnose 4.1

Septoria leaf spot 4.1

Crown gall 1.1

Orange rust .8

Verticillium wilt .7

Double blossom .6

Cane and leaf rust .3

Others 6.7

Total 34.0

Raspberries: 2

Virus diseases 12.4

Anthracnose 7.8

Fruit rots 5.0

Crown gall 4.2

Spur blight 3.9

Verticillium wilt 2.2

Orange rust 1.1

Cane blight .8

Leaf rusts .6

Total 38.0

1 Based on data from New Jersey, New York, North

Carolina, Texas, and Washington.

2 Based on data from Illinois, Maryland, New York,

Ohio, Pennsylvania, and Washington.

Cherries

Commercial production of cherries is seriously reduced by both virus and fungus diseases.

Sour cherry yellows and certain other virus

diseases occur wherever sour cherries are

grown in the United States. In fact, almost

half of the yield losses due to disease during the

period 1951-60 were attributed to viruses.

Usually they do not kill the trees, but they reduce yields by reducing the number of fruitbearing spurs. Leaf spot (Coccomyces) and

brown rot, two fungus diseases, cause much

trouble east of the Rocky Mountains. These

two diseases accounted for one-third of the

estimated annual losses attributed to disease

during the period 1951-60. They are present

most years.

Estimated average annual losses caused by

various diseases of cherries for the period

1951-60 are as follows :

Average

annual

loss 1

Disease (percent)

Virus diseases l^»^

Brown rot ^'^

Coccomyces leaf spot 4.0

Armillaria root rot 1-2

Powdery mildew -2

Black knot -1

Others 3.6

Total 24.0

1 Based on data from the following States: California, Kansas, Maryland, Michigan, New York, Ohio,

Oklahoma, Oregon, Pennsylvania, Rhode Island, Virginia, Washington, and West Virginia.

Citrus (lemons, grapefruit, and oranges)

Citrus trees and fruit are damaged by a

number of fungus diseases; but for the most

part, they can be kept under control without

much effort. More than half of the estimated

losses from diseases reported for the period

1951-60 were caused by wood and root rots,

and fruit and leaf spots.

On the other hand, several virus diseases,

but especially tristeza, menace the very existence of the citrus industry. The virus diseases

occur in Florida, along the Gulf Coast, and in

California and are estimated to kill up to 1

million trees each year. Trees affected with

tristeza gradually lose vigor and become less

productive for several years before their death.

Trees of sweet orange on sour orange rootstock

are killed or severely damaged when infected

with the causal virus.

Estimated average annual losses caused by

various diseases of lemons for the period 1951-

60 are as follows :

Average

annual

loss 1

Disease (percent)

Sieve-tube necrosis 9.9

Shellbark Q[O

Root and foot rot 4.8

Fruit rots 3^0

Psorosis *5

Wood rot [5

Blossom blights [2

Twig blights 'i

Total 25^0

1 Based on data from California.

Estimated average annual losses caused by

various diseases of oranges and grapefruit for

the period 1951-60 are as follows :

Average annual

loss 1

_. Orange Chrapefmit

Disease (percent) (percent)

Root and foot rot 3.2 0.4

Psorosis 2.0 .4

Exocortis 1.9 *9
LOSSES IN AGKICULTURE 21

Average annual

loss 1

Orange Grapefruit

Disease (percent) (percent)

Tristeza 19 .1

Fruit and leaf spots 1.3 .2

Wood and heart rots 1.3 .3

Blossom blight .1 .1

"Stubborn" disease .1 .1

Twig blight .1 .1

Xyloporosis .1 .1

Total 12.0 2.0

1 Based on data from California, Florida, and Texas.

Cranberries

The main disease problem in cranberries is

fruit rots. Fruit rots are caused by a number

of fungi, which were responsible for estimated

average annual losses in yield of 8.7 percent

during the period 1951-60 according to data

from Massachusetts, New Jersey, Washington,

and Wisconsin. Damage is initiated at blossom

time, but the rot phase does not appear until

near harvest. Some rot is present every year

but severity depends on weather. Twig dieback, twig blight, and other diseases each

caused losses estimated at 0.1 percent.

Filberts (hazelnuts)

Filberts are grown commercially in Oregon

and Washington. Bacterial blight is present

in all plantings and was responsible for the

estimated average annual losses of 4 percent

reported for the period 1951-60. The causal

organism attacks the buds, leaves, branches,

and trunk of the trees. It rarely attacks nuts

directly but reduces the size of the crop by

killing the fruiting twigs.

Grapes

Climatic factors are so important in commercial grape production that the high-quality

vinifera, or European, table grapes can be

grown readily only in the Western States,

where more than 90 percent of the U.S. grapes

are grown.

In the East, American bunch grapes are

damaged primarily by black rot and dead arm.

The black rot fungus infects all the green parts

of the plant and causes severe rotting of the

fruit. Black rot is much more difficult to control in the Southeast than in other areas. Dead

arm, which occurs also in California, kills the

main branches of the vines.

The virus-induced Pierce's disease limits culture of bunch grapes in the South and often

kills all vines in a planting. In certain parts

of California, the causal virus has become

established and precludes growing of European

grapes.

Information developed during the 1950's indicates that at least one-seventh of the potential

production of vinifera grapes is lost to other

virus diseases. These virus diseases reduce

vigor, yield, or sugar content.

Estimated average annual losses caused by

various diseases of grapes for the period 1951-

60 are as follows :

Average

annual

loss

Disease (percent)

Leaf roll 8.4

Black measles 5.0

Fanleaf, yellow mosaic, and vein banding 5.0

Summer bunch rot 2.2

Dead arm 2.0

Powdery mildew 1.8

Fruit rots 1.0

Piercers disease .5

Armillaria root rot .2

Black rot .2

Yellow vein .2

Anthracnose .1

Downy mildew .1

Others .3

Total 27.0

Peaches

East of the Rocky Mountains bacterial leaf

spot is probably the most serious disease with

which peach growers have to contend. The continued defoliation year after year weakens the

trees and predisposes them to winter injury.

In some areas bacterial leaf spot is so destructive that many high-quality varieties are not

grown because of their susceptibility. Bacterial

leaf spot caused about one-fifth of the total

estimated losses from disease for the period

1951-60.

Brown rots, scab, and leaf curl fungus

diseases are widely distributed in the United

States. They caused somewhat less than half

the estimated losses of peaches reported. In

certain seasons they cause extensive losses,

particularly in the humid East, and sometimes

brown rot and leaf curl cause losses even in

western orchards.

Peach canker, another fungus disease sometimes called constriction disease, appears to

be getting more troublesome in some peachgrowing areas in the Midwest and the East.

The virus diseases phony and peach mosaic

seem to be under control. Phony was brought

under control by following an eradication program involving the removal of infected trees.

Also contributing to the success of this program was use of organic insecticides, which

control the insect vectors.

Estimated average annual losses caused by

various diseases of peaches for the period 1951-

60 are as follows :
22 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

Average

annual

loss 1

Disease (percent)

Brown rots 4.5

Bacterial leaf spot 2.8

Scab L2

Leaf curl .8

Mosaic .7

Peach canker (constriction disease) .6

Crown gall .5

Miscellaneous virus diseases .5

Phony peach mosaic .5

Coryneum blight .3

Crown or root rot .3

Armillaria root rot .2

Bacterial canker .2

Powdery mildew .1

Rust .1

Others .7

Total 14.0

1 Based on data from Alabama, California, Delaware,

Georgia, Illinois, Kansas, Maryland, Michigan, New

Hampshire, New York, North Carolina, Pennsylvania,

Ohio, Oklahoma, Oregon, Rhode Island, South Carolina,

Virginia, Washington, and West Virginia.

Pears

Except in a few isolated areas, the destructive fireblight (bacterial pear blight) has restricted commercial production of high-qualitypears almost exclusively to the Pacific Coast

States. In the arid climate of those States, pear

growing can be profitable even though none of

the orchards are entirely free from fireblight.

In fact, this disease accounts for about onesixth of the losses reported in table 6.

Pear decline, a serious disorder of pear

trees, occurs in the pear-growing areas on the

Pacific Coast, where it has killed many thousands of trees. Symptoms are of two general

types: (1) quick wilting and sudden death of

trees, often within a week; and (2) slow decline

characterized by cessation of growth, failure to

set fruit, and progressive weakening of trees,

eventually ending in death, usually in 1 or 2

years. The cause of pear decline was recently

determined to be a virus, carried by the pear

psyllid. About three-quarters of the estimated

losses in pear yields (in California, Oregon,

and Washington) reported for the period 1951-

60 can be traced to pear decline.

Estimated average annual losses caused by

the various diseases of pears for the period

1951-60 are as follows :

Average

annual

loss 1

Disease (percent)

Pear decline __ ^2.2

Fireblight ^-^

Leaf blight -^

Scab — -^

Leaf spot — -fPowdery mildew ••*

Average

annual

loss^

Disease (percent)

Sooty blotch '-^

Stony pit 'g

Others '

Total -^'-^

1 Based on data from California, Georgia, Illinois,

Kansas, Michigan, New Hampshire New York, Ohio,

Oklahoma, Oregon, Pennsylvania, Rhode Island, boutn

Carolina, and Washington.

Pecans

The commercial pecan industry is in the

South from South Carolina through Georgia

and Florida and westward to Texas, Oklahoma,

and Arizona. Scab is present throughout this

region and is probably the most damaging

disease that affects the crop. Scab caused about

half of the total estimated losses reported for

the period 1951-60. It is especially damaging

on susceptible varieties, but fortunately only

one-tenth of the acreage is planted to these

varieties. Leaf spots due to various fungi,

crown gall, and nutritional troubles all reduce

the size of the crop. Bunch, a ruinous disease

of undetermined etiology, has spread rapidly

in the Mississippi Delta area in the last few

years.

Estimated average annual losses caused by

various diseases of pecans for the period 1951-

60 are as follows :

Average

annuxil

loss'^

Disease (percent)

Scab 9.8

Brown leaf spot 4.0

Downy spot 3.0

Leaf blotch 2.0

Pink mold 1.0

Powdery mildew 1.0

Crown gall .1

Nursery blight .1

Total 21.0

1 Based on data from Arizona, Georgia, Oklahoma,

South Carolina, and Texas.

Plums and fresh prunes

Brown rot is the most destructive fungus

disease of plums and prunes. It caused about

half of the estimated losses in yield reported

for the period 1951-60.

In the Southeastern States bacterial leaf spot

is probably more severe on plums and prunes

than on peaches. Fortunately, it has not been

found on these fruit crops in the Far West.

Estimated average annual losses caused by

the various diseases of plums and fresh prunes

for the period 1951-60 are as follows :
LOSSES IN AGRICULTURE 23

Average

annual

loss 1

(percent)

Brown rot 4.6

Plum pocket 1.9

Bacterial leaf spot 1.3

Black knot 1.0

Armillaria root rot .4

Leaf spot .3

Others .5

Total 10.0

1 Based on data from Alabama, California, Georgia,

Kansas, Maryland, New York, Ohio, Oregon, Pennsylvania, Rhode Island, South Carolina, Virginia, Washington, and West Virginia.

Sfrawberr'ies

Strawberry fruit rots, principally gray mold,

account for more than half the estimated losses

in yield reported for the period 1951-60. Losses

vary greatly from year to year. Experimental

data from spray tests indicate that losses are

considerably higher than previously reported.

Losses from virus diseases, which account

for one-fifth of the total losses, were markedly

reduced during the period 1951-60 as the result of propagation and certification of virusfree stocks. With the development of virusfree stocks, a basis for comparison with the

almost universally infected commercial plants

was available. Such comparisons indicated

much greater losses than previously reported.

Losses from red stele were low for 1951-60

because of the development and use of resistant

varieties of high commercial quality. Verticillium wilt, a major disease in the California

area until recently, is now almost completely

controlled.

Estimated average annual losses caused by

various diseases of strawberries for the period

1951-60 are as follows :

Ave7^age

annual

loss

Disease (percent)

Fruit rots 15.0

Virus diseases 5.0

Leaf diseases 2.0

Verticillium wilt 2.0

Powdery mildew .5

Red stele .5

Others 1.0

Total 26.0

Tung trees

Tung trees are cultivated commercially in a

narrow belt approximately 100 miles wide along

the Gulf of Mexico from eastern Texas to

Florida. In general, this crop has been free

of fungus diseases. Recently, losses from

mycosphaerella leaf spot (1.8 percent) increased slightly. Clitocybe root rot caused

estimated average annual losses of about 0^

percent during the period 1951-60.

Walnuts

Bacterial blight, which is destructive in the

extensive commercial plantings of walnuts in

California and Oregon, caused estimated average annual losses of about 15 percent during

the period 1951-60. The disease primarily

affects the nuts, but it may also spot leaves and

blight blossom clusters early in the spring.

Black line, a disease of undetermined etiology,

caused estimated losses of about 3 percent

annually.

VEGETABLE CROPS

The estimates of disease losses in vegetable

crops (table 7) include only those for the important commercial crops on which reasonably

accurate data are available. No attempt was

made to estimate losses in home gardens and

other noncommercial plantings. The estimated

annual losses caused by vegetable diseases for

the period 1951-60 averaged $290,389,000.

Artichokes

The gray mold fungus causes the greatest

disease losses in artichokes. It decays the older

bud scales, the growing buds, and the stem and

lateral branches. Average annual losses were

estimated at 3 percent for the period 1951-60.

Curly dwarf, a virus disease, has recently

caused some losses (1 percent), chiefly in California where most of the crop is grown. It

stunts growth and causes the plants to die

prematurely; the result is a reduction in yield

(number of heads). Root and stem rots also

cause estimated average annual losses of 1

percent.

Asparagus

Most disease losses in asparagus are caused

by rust; average annual losses were estimated

at 7 percent for the period 1951-60. The rust

fungus injures the stems that develop after the

cutting season is over and causes the needlelike branches to fall. This injury to the top

growth reduces storage of food reserves in the

fleshy roots and consequently reduces vigor and

yield of the plants the next year. The marketable portions of the plants, however, are not infected. Rust occurs throughout the United

States, but is most severe in humid regions.

Stalk wilt and root decay also cause some losses

in asparagus (about 1 percent each).

Beans, green Uma

Downy mildew, root rots, stem anthracnose,

and seed decay cause more losses in lima beans

than do other diseases. Root rots and seed decay
24 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

cause more damage to the large-seeded limas

than to other types. Losses are due to reduced

yield and quality.

In years when downy mildew is severe in

Delaware and New Jersey, it causes considerable loss. Wherever lima beans are grown in

the East under humid and other conditions

favorable for anthracnose, this disease causes

some loss. Bacterial blights cause less damage

in lima beans than they do in snap beans.

Estimated average annual losses caused by

specific diseases of lima beans for the period

1951-60 are as follows :

Average

annual

loss

Disease (percent)

Downy mildew 4.0

Root rots 2.0

Stem anthracnose 2.0

Average

ayinual

loss

Disease (percent)

Seed decay ^-^

Seed pitting -^

Bacterial blights -g

Bacterial spot -^

Total 10.0

Beans, green snap

Losses in snap beans are caused principally

by fusarium root rot, rhizoctonia root rot,

sclerotinia wilt, and virus-induced diseases including mosaics and curly top. Seed decay

caused by soil fungi can result in considerable

damage in certain seasons.

In humid areas and where hail occurs, the

bacterial blights can be damaging. Rust is

TABLE 7.—VEGETABLES : Estimated average annual losses due to diseases, 1951-60

Commodity

Production

unit

Loss from potential production i

Reduction 2 Quantity Value

Artichokes HundredweightAsparagus do

Beans :

Green lima do

Green snap do

Beets, table do

Broccoli _-do

Cabbage do

Cantaloups do

Carrots do

Cauliflower do

Celery do

Corn, sweet —do

Cowpeas Bushel

Cucumbers:

Fresh market HundredweightGreenhouse do

Pickling Bushel

Eggplant HundredweightEscarole (endive)

Kale

Lettuce, field-grown

Melons, honeydew and honeyball

Mushrooms

Onions

Peas, green

Peppers, green sweet

Potatoes

Shallots

Spinach

Sweetpotatoes __do_

Tomatoes :

Fresh market —do_

Greenhouse —do_

Plant bed Crate

Processing Ton__

Watermelons —do_

Total

do_

do_

do_

—do

__do

__do

__do

—do

—do

—do

—do

Percent IfiOO units

5 18

9 347

10 262

20 2,586

3 115

2 46

8 2,229

16 2,070

8 1,284

8 233

17 2,955

8 1,041

8 1,634

18 808

8 2

11 1,645

12 64

6 46

8 16

12 4,278

14 229

16 243

20 5,379

23 2,656

14 450

19 45,052

21 35

20 1,009

18 2,173

21 4,536

20

8

22

3 124

~916

10 3,125

IfiOO dollars

162

4,073

1,922

17,651

145

369

3,973

9,126

3,845

1,476

10,866

1,034

6,786

4,110

42

2,261

327

214

70

17,274

1,119

6,813

13,901

11,976

3,752

89,527

245

3,753

8,932

31,800

3 4,038

3 522

23,868

4,417

290,389

1 See table 2, footnote 1.

2 See table 2, footnote 2.

3 Based on data from the 1959 Census of Agriculture.
LOSSES IN AGRICULTURE 25

common in the coastal sections in the South and

recently has been of concern along the Atlantic

Seaboard. The curly top virus causes little or

no damage where snap beans are grown for

market or processing but prevents their production in many western areas such as southern

Idaho, eastern Oregon, and central Washington.

The losses are due not only to reduced yield, but

also to decreased pod quality because of decay

and spotting.

Estimated average annual losses caused by

various diseases of snap beans for the period

1951-60 are as follows :

Average

annual

loss

Disease (percent)

Fusarium root rot 6.0

Mosaics 8.0

Rhizoctonia root rot 3.0

Bacterial blights 2.0

Sclerotinia wüt 2.0

Curly top 1.0

Powdery mildew 1.0

Rust 1.0

Anthracnose .5

Southern blight .5

Total 20.0

Beets, table

Table beets are not generally injured greatly

by diseases. Most losses are caused by seedling

diseases, downy mildew, leaf spots, and boron

deficiency (black spot). Black-root fungi cause

damping-off of seedlings wherever beets are

grown. Downy mildew is confined almost entirely to the Pacific Coast. Cercospora leaf

spot is common east of the Continental Divide

but does not cause severe losses. Boron deficiency is probably the most damaging disease

of beets grovra for canning in the Northern

States. Losses are due not only to reduced yield

but also to decreased quality because of root

necrosis.

Estimated average annual losses caused by

various diseases of table beets for the period

1951-60 are as follows :

Average

annual

loss

Disease (percent)

Downy mildew 1.0

Black spot (boron deficiency) 1.0

Black root .5

Leaf spots .5

Total 3.0

Broceo//

Downy mildew causes the greatest losses in

broccoli; average annual losses for the period

1951-60 were estimated at 1 percent. The

downy mildew fungus causes numerous black

spots of different sizes, which reduce the

quality of this crop wherever it is grown Other

diseases cause additional losses of 1 percent.

Cabbage

The diseases responsible for most losses in

cabbage are fusarium yellows, blackleg, clubroot, watery soft rot, black rot, mosaic, and

downy mildew. The losses are due to reduced

yield, reduced size, and decay of the heads.

Yellows caused by a soilbome Fusarium may

occur wherever cabbage is grown. Blackleg is

present in all parts of the Temperate Zone

where susceptible crops are grown intensively.

Clubroot is widespread in Northern United

States, and watery soft rot may be destructive

wherever cabbage is grown. Black rot occurs

chiefly in humid areas. Mosaic occurs throughout the United States, but downy mildew is

most prevalent in the coastal regions.

Estimated average annual losses caused by

various cabbage diseases for the period 1951-60

are as follows :

Average

annual

loss

Disease (percent)

Fusarium yellows 2.5

Clubroot 1.5

Blackleg 1.0

Watery soft rot 1.0

Black rot .5

Others, including downy and powdery mildews,

rhizoctonia root rot, and mosaic 1.5

Total 8.0

Cantaloups

Losses in cantaloups are caused chiefly by

crown blight, leaf diseases, and virus diseases.

The most damaging leaf diseases are downy

and powdery mildews; anthracnose and alternaria leaf spots also cause some losses. Diseases

caused by watermelon mosaic virus, squash

mosaic virus, cucumber mosaic virus, and curly

top virus are responsible for severe damage in

the West. A disease caused by tobacco ring

spot virus is serious in Texas. Minor losses are

caused by bacterial wilt.

Losses from many of the diseases affecting

cantaloups are regional. Crown blight is a

major disease in the West, especially the Southwest. Downy mildew as a major disease is confined largely to the Atlantic Seaboard and the

Gulf States. Anthracnose, alternaria leaf spot,

and bacterial wilt are destructive only in humid

areas east of the Continental Divide. On the

other hand, powdery mildew is most destructive in Arizona and California. Mosaics are

much more damaging in Arizona, California,

Florida, Texas, and Washington than in the

Central and Eastern States. Curly top is confined to areas west of the Continental Divide,

where the insect vector, the beet leafhopper.
26 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

occurs. The losses are due not only to a reduced yield but also to decreased quality because of fruit blemishes.

Estimated average annual losses caused by

specific cantaloup diseases for the period 1951-

60 are as follows :

Average

minual

. loss

Disease (percent)

Crown blight 4.0

Virus diseases 3.5

Powdery mildew 3.0

Downy mildew 2.5

Alternaria leaf spot 1.0

Anthracnose 1.0

Gummy stem blight .5

Fusarium wilt .3

Bacterial wilt .2

Total 16.0

CarroH

Most of the disease losses in carrots during

the period 1951-60 were caused by bacterial

blight (estimated at 2 percent annually), alternaria and cercospora leaf blights (2 percent),

and yellows caused by the aster yellow virus

(2 percent). Losses caused by other diseases

were also estimated at 2 percent, making a total

of 8 percent.

Bacterial blight occurs chiefly in California

and other Southwestern States. It occurs on

both roots and seeds. Alternaria and cercospora

blights, which attack the foliage, occur wherever carrots are grown. Aster yellows is restricted to Western United States. It not only

reduces yield but also decreases the value of

roots because of their atypical shapes and

sizes.

Cauliflower

The diseases responsible for the greatest

cauliflower losses are clubroot, black rot, blackleg, downy mildew, and mosaic. Annual losses

estimated at 1 percent were caused by each of

these during the period 1951-60, as compared

with losses of 3 percent caused by miscellaneous other diseases.

Clubroot is widespread in the humid regions

and blackleg is very widespread. Downy

mildew is most prevalent in coastal areas and

mosaic may occur throughout the United States.

Losses are due to reduced yield, head discoloration, and curd damage.

Celery

Celery is subject to losses caused by leaf

blights, fusarium yellows (wilt), virus diseases,

and nonparasitic disorders. The major leaf

diseases are early and late blights, but bacterial

leaf spot caused some losses. Cucumber mosaic

and western aster yellows each caused annual

losses estimated at 2.5 percent during the period

1951-60. The major nonparasitic diseases are

blackheart (caused by sudden saturation of the

soil with water) and cracked stem (due to

boron deficiency in the soil).

Most of the major diseases of celery occur

wherever the crop is grown. Western aster

yellows, which is limited to Western States,

is damaging chiefly in California. Losses are

due to reduced yield. In addition, blemishes and

bitterness caused by some diseases reduce

quality.

Estimated average annual losses caused by

various celery diseases for the period 1951-

60 are as follows :

Average

annual

loss

Disease (percent)

Early blight 4.0

Late blight 4.0

Cucumber mosaic 2.5

Western aster yellows 2.5

Bacterial leaf spot 1-0

Blackheart 1.0

Cracked stem 1.0

Fusarium yellows 1.0

Total 17.0

Corn, sweet

The principal diseases that damage sweet

corn are bacterial wilt and helminthosporium

leaf blights.

Bacterial wilt occurs throughout the Corn

Belt and in the Eastern United States. Smut,

leaf blights, and seedling diseases occur in all

corn-growing areas. In Florida, where corn

acreages have increased, losses from leaf

blights are severe if fungicides are not applied

regularly. Smut also has been severe in

Florida. Seedling diseases are more severe in

cold and humid areas.

Estimated average annual losses caused by

the various diseases of sweet corn for the

period 1951-60 are as follows :

Average

annual

loss

Disease (percent)

Bacterial wilt 4.0

Helminthosporium leaf blights 2.5

Seedling diseases 1.0

Others, including smut .5

Total 8JÖ~

Cowpeas, edible

Throughout the growing areas the greatest

losses in cowpeas during the period 1951-60

were due to fusarium wilt (estimated at 4 percent annually) and cladosporium leaf and pod

spot (2 percent). Charcoal rot and mosaics

each caused estimated losses of 1 percent. These
LOSSES IN AGRICULTURE 27

losses were due not only to reduced yield but

also to decreased pod quality because of

blemishes and deformation.

Cucumbers, fresh market

Disease losses in cucumbers grown for fresh

market are caused chiefly by downy mildew,

anthracnose, angular leaf spot, and cucumber

mosaic. Less severe losses are caused by

various other diseases, of which scab is an

example.

Loss from downy mildew is probably

greatest, although the disease is conñned to

the Atlantic Coast. Anthracnose and angular

leaf spot are widespread in humid regions east

of the Continental Divide, and virus diseases

are a major cause of losses in many cucumbergrowing areas. Scab is troublesome chiefly in

the northern tier of States from Minnesota to

Maine, but it occurs on fall cucumbers in North

Carolina and causes minor losses in Maryland

and New Jersey. The losses are due not only

to reduced yield but also to decreased quality

because of blemished and deformed fruit.

Estimated average annual losses caused by

various diseases of cucumbers grown for fresh

market for the period 1951-60 are as follows:

Avey^age

annual

loss

Disease (percent)

Anthracnose 3.5

Downy mildew 3.5

Angular leaf spot 2.0

Cucumber mosaic 2.0

Powdery mildew 1.5

Alternaría blight 1.0

Cercospora leaf spot 1.0

Tobacco ringspot 1.0

Watermelon mosaic 1.0

Scab .5

Fusarium wilt .3

Pythium fruit rot .3

Bacterial wilt .2

Diplodia fruit rot .2

Total 18.0

Cucumbers, greenhouse

The principal disease losses in cucumbers in

the greenhouse are caused by powdery mildew

and cucumber mosaic. Occasionally there are

minor losses from bacterial wilt and fusarium

foot rot. All these diseases may occur and reduce yields wherever the crop is grown.

Estimated average annual losses caused by

specific diseases of greenhouse cucumbers for

the period 1951-60 are as follows : Average

annual

Disease (percent)

Powdery mildew 6.5

Cucumber mosaic 1.0

Bacterial wilt .3

Fusarium foot rot .2

Total 8.0

Cucumbers, pkkVmg

The major disease losses in cucumbers grown

for pickling are caused by cucumber mosaic

tobacco ringspot, scab, and angular leaf spot'

About 60 percent of the pickling cucumbers

are grown in the North Central States, particularly Illinois, Indiana, Michigan, Minnesota,

Ohio, and Wisconsin. Another 25 percent are

grown in Alabama, Georgia, Maryland, Mississippi, North Carolina, and South Carolina.

California, Colorado, and Oregon produce most

of the western crop. The relative severity of

the various diseases is determined by the location. Mosaic is especially prevalent in the

North Central States. Bacterial wilt, also common there, is rarely found in the South. Scab

is most damaging in the northern tier of States

from Minnesota to Maine. The losses are due

not only to reduced yield but also to decreased

quality because of fruit blemishes and deformation. Angular leaf spot is damaging some

years in all production areas east of the Rocky

Mountains. Tobacco ringspot causes losses

from Texas northward into Wisconsin.

Estimated average annual losses caused by

specific diseases of cucumbers grown for

pickling for the period 1951-60 are as follows:

Average

annual

loss

Disease (percent)

Cucumber mosaic 2.5

Scab 2.5

Tobacco ringspot 2.0

Angular leaf spot 1-5

Alternaria leaf spot -5

Anthracnose .5

Downy mildew -5

Powdery mildew -5

Bacterial wilt .2

Cercospora leaf spot .2

Pythium fruit rot .1

Total 11.0

Eggplant

The major diseases of eggplant are fruit rots

and leaf diseases, which occur wherever the

crop is grown but are most damaging in the

South. Verticilhum wilt causes some losses in

the North. The losses are due to reduced yield

and quality.

Estimated average annual losses caused by

various eggplant diseases for the period 1951-

60 are as follows : Average

annual

loss

Disease (percent)

Phomopsis blight ^-^

Cercospora leaf spot 2.0

Sclerotinia stem rot j-^

Colletotrichum fruit rot j-^

Verticillium wilt 1-^

Yellows -^

Total 12.0
28 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

Escarole (endive)

Disease losses in escarole during the period

1951-60 were caused by stem and leaf spots

(estimated at 2 percent annually), bacterial

soft rot (2 percent), aster yellows (1 percent),

and miscellaneous diseases (1 percent). All

these diseases occur in Florida, where most of

the crop is grown. Losses are due not only to

reduced yield but also to decreased quality because of discoloration.

Kale

Blackleg, black rots, clubroot, downy mildew,

and fusarium yellows—all are diseases of kale,

a commercial crop only in Virginia. They each

caused average annual losses estimated at 1

percent during the period 1951-60. In addition, miscellaneous diseases caused losses of 3

percent. The diseases reduced both yield and

quality by stunting the plants and injuring the

edible leaves.

Lettuce, field-grown

Field-grown lettuce is damaged severely by

lettuce mosaic, a virus disease. Downy mildew,

which withers the leaves, is another cause of

heavy losses. Big vein and tipburn, the latter

a nonparasitic disease, often damage lettuce.

Bottom and sclerotinia rots decay stems and

leaves.

Mosaic and downy mildew are widespread,

particularly in the western growing areas, but

aster yellows is found chiefly in the Northeastern States. Tipburn and bottom and

sclerotinia rots occur wherever lettuce is

grown. The greatest losses from disease are

due to decreased quality caused by discoloration,

deformities, and off-flavor.

Estimated average annual losses caused by

various diseases of field-grown lettuce for the

period 1951-60 are as follows :

Average

annual

loss

Disease (percent)

Mosaic 4.0

Downy mildew 3.0

Tipburn 1.5

Big" vein 1.0

Aster yellows 1.0

Damping-off - .5

Others, including bottom and sclerotinia rots l.Q

Total 12.0

Melons, honeydew and honeyball

Honeydew and honeyball melons are damaged by crown blight, which caused average

annual losses estimated at 6 percent during the

period 1951-60. Severe losses are also caused

by powdery mildew (4 percent). Stunting of

the plants and reduced yields result from infection by the watermelon mosaic virus, curcurbit latent virus, cucumber mosaic virus,

and squash virus (4 percent). All these diseases

are present in Arizona and California, where

nearly all the crop is grown. The losses are due

not only to reduced yield but also to decreased

quality because of blemishes and deformity of

fruit.

Mushrooms

Losses in mushrooms, which occur wherever

the crop is grown, are caused chiefly by pathogenic fungi and bacteria that deform and

blemish the mushrooms and by weedmolds that

compete with the mushrooms for nutrients in

the compost. The weedmolds that cause most

damage are olive green mold, mat, lipstick,

and truffle. Bubbles and brown spot are the

principal diseases caused by pathogens.

Ocasionally these diseases cause almost total

loss.

Estimated average annual losses caused by

different diseases or molds of mushrooms for

the period 1951-60 are as follows :

Average

annual

loss

Disease or mold (percent)

Bubbles - 4.0

Brown spot - - - 2.7

Olive green mold 2.0

Bacterial blotch 1.0

Green mold 1.0

Lipstick mold ^ 1.0

Mat .8

Truffle - .8

Mummy .2

Red spot -- .2

Bacterial pit .1

Mildew .1

Soft mildew .1

Others - 2.0

Total _ 16.0

Onions

Downy mildew, fusarium root rots, neck

rot, ping root, purple blotch, and smudge cause

more losses in onions than do other diseases.

They reduce yields because the bulbs of infected plants remain undersized and rot.

Smudge occurs only on white onions. Downy

mildew is most destructive in California,

Louisiana, Michigan, New York, and Oregon.

In unusually cool seasons it may become severe

in the Midwest, Colorado, and Texas. Neck rot

is most severe in upper North-central and

Northeastern United States. Pink root is prevalent in the Rio Grande Valley and Central

California. Fusarium root rots and purple

blotch are present wherever onions are grown

intensively.

Estimated average annual losses caused by

the various diseases of onions for the period

1951-60 are as follows :
LOSSES IN AGRICULTURE 29

Average

annual

loss

Disease (percent)

Fusarium root rots 4.0

Neck rot 4.0

Pink root 3.0

Purple blotch 3.0

Downy mildew 1.0

Smudge 1.0

Others 4.0

Total 20.0

Peas, green

The greatest disease losses in green peas are

caused by several root rots, all general in occurrence throughout the various pea-growing

areas. Severe losses are often caused by five

viruses that infect peas, particularly in the

Pacific Northwest. Of less importance are

wilts, and ascochyta and bacterial blights. The

losses are due primarily to reduced yield.

Estimated average annual losses caused by

the various diseases of green peas for the

period 1951-60 are as follows : Average

annual

loss

Disease (percent)

Root rots 10.0

Virus diseases 6.0

Ascochyta blight 2.0

Fusarium wilts 2.0

Bacterial blight 1.0

Powdery mildew 1.0

Others 1.0

Total 23.0

Peppers, green sweei

Disease losses in peppers are due principally

to leaf spots, fruit spots and rots, and mosaics.

Anthracnose fruit rot is also of economic importance, but it causes less damage than the

leaf spots.

Leaf spots and fruit rots occur wherever

peppers are grown in humid areas. Virus

diseases are present in all pepper-growing sections. Fusarium wilt is most prevalent in the

Southwest. Losses are due not only to reduced

yield but also to decreased quality because of

blemished, deformed fruit.

Estimated average annual losses caused by

the various diseases of green sweet peppers

for the period 1951-60 are as follows :

Average

annual

loss

Disease (percent)

Bacterial spot 6.0

Anthracnose 2.0

Fusarium wilt 1.5

Cercospora leaf spot 1.0

Phytophthora blight 1.0

Tobacco mosaic 1.0

Cucumber mosaic .5

Potato mosaic caused by virus Y .5

Tobacco etch mosaic .5

Total 14.0

Potatoes

Potatoes in the field are severely injured by

diseases. Late blight is manifested by foliage

injury and tuber rot. It is a major cause of

losses in many of the large producing areas in

the Central and Atlantic States, and at times

in some sections of California. Verticillium wilt

is another major cause of losses, particularly

in the West. Leaf roll, a virus disease, ranks

with late blight and verticillium wilt as a cause

of losses in potatoes ; it reduces both yield and

quality.

Less severe but important losses result from

scab, early blight, rhizoctonia black scurf,

fusarium wilt, blackleg, and ring rot. Most of

these diseases may occur wherever potatoes

are grown, but they are particularly prevalent

in the North Atlantic, North Central, and

Pacific Coast States. Since viruses are carried

in seed tubers, virus diseases occur wherever

potatoes are grown. Losses result not only

from decreased yield and quality of tubers, but

also from increased costs of production because

of the necessity for planting certified seed and

for keeping the plants comparatively free from

infection.

Estimated average annual losses caused by

various potato diseases for the period 1951-60

are as follows :

Average

annual

loss

Disease (percent)

Late blight 4.0

Leaf roH 3.0

Verticillium wilt 2.7

Scab 1-5

Early blight 1-0

Latent mosaic |-^

Mild mosaic 1-^

Rhizoctonia black scurf 1-^

Rugose mosaic ^-^

Blackleg -^

Fusarium wilt -^

Ring rot -^

Spindle tuber -^

Bacterial brown rot -1

Others ^-^

Total 19.0

Shallots

Greatest losses in shallots are caused by yellow dwarf, a virus disease. Other losses are

caused by the same diseases that occur on

onions, largely in Louisiana, where the crop

is grown. ^ , ,

Estimated average annual losses caused by

various diseases of shallots for the period 1951-

60 are as follows : Average

annual

loss

Disease (percent)

Yellow dwarf ^'^

Pink root *^'"
30 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

Average

annual

j^. loss

Visease (percent)

Downy mildew 2.0

Fusarium root rots 2.0

Neck rot 2.0

Purple blotch 2.0

Smudge 2.0

Others 4.0

Total 21.0

Spinach

Downy mildew, which damages the leaves, is

a major cause of losses wherever susceptible

varieties of spinach are grown, particularly in

humid coastal areas. White rust is epidemic

in Arkansas, Oklahoma, Texas, and Virginia

but has not caused losses elsewhere. Dampingoff is damaging to seedling plants in all plantings. Fusarium wilt causes losses in Texas and

Virginia. Spinach blight is particularly severe

on fall and winter crops. Curly top, which

causes heavy losses west of the Continental

Divide, limits production in some areas; occasionally the disease appears also in southwestern Texas. Malva yellows causes severe losses

in California. Losses are due not only to reduced yield but also to decreased quality because of blemished leaves and petioles.

Estimated average annual losses caused by

specific spinach diseases for the period 1951-60

are as follows :

Average

annual

loss

Disease (percent)

Downy mildew 5.0

White rust 5.0

Damping-off 3.0

Malva yellows 2.0

Curly top 1.5

Anthracnose 1.0

Fusarium wilt 1.0

Spinach blight 1.0

Cercospora leaf spot .5

Total 20.0

Sweetpofatoes

Field losses in sweetpotatoes are due primarily to stem rot and black rot. Stem rot

causes losses in yield by killing from 10 to 50

percent of the crop of susceptible dry-flesh

varieties in some areas. Black rot reduces yield

in all areas where sweetpotatoes are grown.

Yellow dwarf reduces yields; it is especially

prevalent in California, Georgia, and New

Jersey. Roots affected by internal cork are inedible, but it causes greater losses as a storage

disease than as a field disease. Leaf spot, scurf,

and soil rot all reduce yields and lower eating

quality throughout the sweetpotato-growing

areas.

Estimated average annual losses caused by

specific sweetpotato diseases for the period

1951-60 are as follows :

Average

annual

loss

Disease (percent)

Stem rot 7.0

Black rot 5.0

Yellow dwarf 2.0

Internal cork 1«5

Leaf spot 1-5

Scurf .5

Soil rot (pox) -5

Total 18.0

Tomatoes, fresh market

The diseases that cause the most severe losses

in fresh market tomatoes are leaf spots, virus

diseases, and fruit rots. The most important

wilt is verticillium wilt, which affects the fresh

market tomato crop to some extent in southern

Florida and certain areas in the Midwest and

the Middle Atlantic States. Defoliation associated with leaf spots reduces yields and exposes fruit to sunscald. Some leaf spots occur

only on the foliage and stems, but other pathogens that infect leaves also cause rot of fruit.

Septoria leaf spot and gray leaf spot are the

chief diseases that affect only the leaves. Leaf

mold causes minor losses. Early and late

blights cause both leaf spotting and fruit rot;

but late blight, always a major threat to tomatoes, is most injurious as a fruit rot. Most of

these diseases are widespread in humid areas

east of the Continental Divide. Leaf mold, however, occurs chiefly in the South Atlantic States,

and gray leaf spot has spread from the South

into the North Central and Middle Atlantic

States. Bacterial wilt causes minor losses in

Florida. Some fruit rots (anthracnose, soil rot,

and buckeye rot) are caused by fungi that do

not seriously affect the leaves, and they cause

only minor losses to the fresh market crop.

Viruses infect tomatoes wherever they

are grown. The tobacco mosaic virus causes

some reduction in yield in most fields, but other

viruses cause only minor losses east of the

Rocky Mountains except in southwest Texas,

where some losses occur most years.

Blossom-end rot, a nonparasitic disorder due

to high temperatures and lack of soil moisture,

causes some injury throughout the United

States.

Estimated average annual losses caused by

the specific diseases of fresh market tomatoes

for the period 1951-60 are as follows :

Average

annual

_.. loss

Disease (percent)

Tobacco mosaic 50

Gray leaf spot 3*0
LOSSES IN AGRICULTURE 31

Average

annual

loss

Disease (percent)

Verticillium wilt 3.0

Bacterial spot 1.0

Blossom-end rot 1.0

Curly top 1.0

Early blight (alternarla leaf spot) _. 1.0

Fusarium wilt -- 1.0

Bacterial wilt .5

Late blight .5

Leaf mold .5

Septoria leaf spot .5

Others 3.0

Total 21.0

Tomatoes, greenhouse

Leaf mold and tobacco mosaic continue to be

the primary causes of fruit-production losses

to greenhouse tomato growers. Blotchy ripening, gray wall, or internal browning of fruit

may cause severe losses.

Estimated average annual losses caused by

various diseases of greenhouse tomatoes for

the period 1951-60 are as follows :

Average

annual

loss

Disease (percent)

Leaf mold 8.0

Tobacco mosaic '7.0

Tobacco streak 1.0

Others 4.0

Total 20.0

Tomatoes, transplant

Diseases were estimated to have caused total

losses of 8 percent each year to the southern

plant-bed tomato industry during the period

1951-60. Alternaría leaf spot (3 percent) and

bacterial spot (2.5 percent) caused the greatest losses, mostly in Georgia. Rhizoctonia

canker and alternaria stem canker caused estimated losses of 1 percent each, and late blight

caused losses of 0.5 percent.

Tomatoes, processing

Diseases causing the most severe losses in

tomatoes for processing are anthracnose in the

East and verticillium wilt in the West. Some

losses due to verticillium wilt occur in the Middle Atlantic States. Virus diseases and nonparasitic disorders are just as prevalent on

tomatoes for processing as on fresh market

tomatoes.

Estimated average annual losses caused by

the various diseases of processing tomatoes for

the period 1951-60 are as follows :

Average

annual

loss

Disease (percent)

Anthracnose f.O

Verticillium wilt 4.Ü

Average

annual

«.. loss

Disease (percent)

Curly top 3.0

Fusarium wilt 2.0

Gray leaf spot 2.0

Bacterial spot i*o

Tobacco mosaic I'o

Others 5.0

Total 22.0

Watermelons

The anthracnose fungus, which can cause defoliation of vines and fruit rot, is the most

damaging disease of watermelons. It is widespread in humid areas east of the Continental

Divide. Downy mildew is severe in the Atlantic and Gulf States ; watermelon mosaic in the

South, particularly the Southwest ; and tobacco

ring spot in Oklahoma and Texas. Fusarium

wilt causes considerable damage wherever the

crop is grown. Some years gummy stem blight

is severe in the South.

Estimated average annual losses caused by

specific watermelon diseases for the period

1951-60 are as follows :

Average

annual

loss

Disease (percent)

Anthracnose — 5-0

Fusarium wilt 2.0

Gummy stem blight 1*0

Watermelon mosaic 1«0

Downy mildew «5

Tobacco ring spot -5

Total 10.0

ORNAMENTAL PLANTS AND SHADE TREES

Estimates of disease losses in ornamental

plants and shade trees (table 8) were limited

to commercial plantings. Except for shade

trees, the estimates do not include losses in

home gardens and landscaping. The average

annual reduction due to diseases for the period

1951-60 was estimated at $14,099,000. Important disease losses in home garden plantmgs

are mentioned even though the percentage of

loss is not reported.

Carnations

Continuous greenhouse culture of carnations,

becoming a general practice, reduces the danger of losses from alternaria blight and rhizoctonia stem rot. Under greenhouse culture these

two diseases cause losses in yield by reducing

plant stands, and losses in flower quality and

size by reducing foliar surface. In wet seasons

alternaria blight builds up on plants maintamed

outside. Considerable losses caused by nonblooming for months occur when such diseased

plants are used later for greenhouse forcing.
32 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

TABLE 8.—ORNAMENTAL CROPS AND SHADE TREES : Estimated average annual losses due to

diseases, 1951-60

Production

unit

Loss from potential production i

Commodity

Reduction 2 Quantity 3 Value 4

Carnations

Chrysanthemums

Foliage plants

Geraniums

Gladiolus (corms)

Lilies

Roses

Shade and ornamental trees 5

Number

r_V. "doIZIIIIIIII

-do

— -do

.— -do

— -do

— -do

Percent

11

11

22

^5

20

15

12

1

IfiOO units

1,290

30,374

3,907

702

95

76

IfiOO dollars

108

2,669

8,425

983

625

986

133

170

Total 14,099

1 See table 2, footnote 1.

2 See table 2, footnote 2.

3 Number of plants or trees from

Agriculture.

the 1959 Census of

4 Based on wholesale prices from the 1959 Census of

Agriculture.

5 Deciduous shade and flowering trees.

Average annual losses from these two diseases

were estimated at 4 percent of the carnation

crop for the period 1951-60.

Wilts, caused by Fusarium and bacteria,

cause estimated annual losses of about 5 percent of the crop. These wilts kill plants in all

stages of growth. Losses are twofold: Total

bench space is not used efficiently and total

flower production is decreased. The cost of

maintaining disease-free propagating stock also

reduces profits to carnation growers. Fusarium

stem rot, a disease distinct from fusarium wilt,

caused losses estimated at 2 percent.

Virus diseases have not proved to be a source

of significant losses in commercial carnation

varieties.

Chrysanihemums

Losses caused by chrysanthemum viruses to

the greenhouse crop decreased during the 10-

year period 1951-60. At the beginning of the

period, viruses threatened to wipe out the industry. Plants infected with viruses such as

stunt are a total loss, for they produce no

flowers and are of no value for further propagation. Verticillium wilt kills the leaves progressively up the stem and thereby lowers the

quality of the flowers and reduces the number

of salable ones. Chrysanthemum diseases lead

to increased costs per cutting, because of the

specialized techniques required to produce

disease-free stock. Disinfection and soil sterilization to control diseases caused by soilborne

agents such as the wilts increase costs of production.

Bacterial wilt is associated with a brown to

black soft rot of stems under warm, humid

conditions. Under cooler and drier conditions

the causal bacterium may remain inactive and

unnoticed. Thus, infected plants may move in

commercial trade and develop conspicuous

symptoms when planted in warm, humid areas.

Ascochyta blight, a disease of chrysanthemum

flowers, stems, and leaves, is caused by a fungus

active over a wide range of temperatures and

adapted to survive and to develop over most

of the United States. Botrytis blight destroys

flowers, leaves, and stems of growing plants.

Stemphylium ray speck disfigures flowers in

field and packing houses during warm, wet

weather.

Estimated average annual losses caused by

chrysanthemum diseases for the period 1951-

60 are as follows :

Average

annual

loss

Disease (percent)

Ascochyta blight 2.0

Bacterial wilt 2.0

Botrytis blight 2.0

Stunt (virus) 2.0

Leaf spots 1.0

Stemphylium ray speck 1.0

Verticillium wilt 1.0

Total 11.0

In garden mums, leaf-spotting fungi defoliate

the plants and reduce both the number and size

of flowers, and the plants are killed by wilts.

Losses caused by viruses are high in the garden crop wherever mums are grown.

FoUage plants

Damping-off of cuttings of foliage plants

and root and stem rots caused by species of

Pythium, Phytophthora, and Rhizoctonia deplete stands. Bacterial soft rots of the leaves

and stem of aroids such as caladiums cause

heavy losses in foliage-plant nurseries.
LOSSES IN AGRICULTURE 33

A few leaf spots may make foliage plants

unsalable. Several fungi disfigure leaves of

foliage plants and cause considerable damage

if they are not controlled by sprays. Labor and

spray materials to control foliar diseases add

to the growers' expenses.

Estimated average annual losses caused by

diseases in foliage plants for the period 1951-

60 are as follows :

Average

annual

loss

Disease (percent)

Damping-off 7.0

Bacterial soft rot 6.0

Stem rots 6.0

Leaf spots 3.0

Total 22.0

Geraniums

During cutting, geraniums (Pelargonium)

are subject to losses from krinkle virus and

other diseases; during greenhouse culture, to

losses from bacterial leaf spot and rots caused

by Pythium; and in garden plantings, to losses

from verticillium wilt, virus yellows, and other

diseases. Geranium losses from these diseases

amounted to an estimated 5 percent annually

during the period 1951-60. Losses are caused

by killing plants or lowering their vigor, by

rotting cuttings, and by reducing flower quality. Yields of salable plants are lowered.

Gladiolus

During the period 1951-60 the gladiolus industry experienced heavy losses due to diseases.

Large expenditures were involved in postharvest and preplanting sorting and chemical

treatment of corms, in quick drying corms after

harvest, in rotation of fields, and particularly

in replacement of stock. In spite of using the

best available control measures, growers may

lose from 5 to 40 percent of susceptible varieties. Fusarium corm rot causes the greatest

loss in warm soils; it is outranked by stromatinia dry rot and botrytis blight in cooler areas.

Cucumber mosaic and virus-induced stunt are

gaining recognition as causes of cull plants.

Botrytis blight affects all parts of the gladiolus plant, and losses are severe in cool, moist

weather. Botrytis causes corm rot in the Northern States when weather is wet at harvesttime

and it causes damaging leaf spot in all growing areas during wet weather.

Curvularia bUght losses are most severe in

young stock grown from seed or cormels. Losses

are caused by defoliation of plants and rotting

of corms.

Fusarium corm rot occurs in the field and in

storage wherever gladiolus are grown. A large

number of plants die in warm soils in spite of

the best available control measures.

Stromatinia dry rot of gladiolus corms, associated with neck rot in plants in the field, results in premature yellowing and death of tops

and mummification of corms. In cool, moist

climates, losses are as high as from botrytis

blight.

Losses from stemphylium leaf spot occur

from Florida to New York at medium temperatures following cool periods. Varieties differ

in susceptibility and hence the losses depend

on the variety grown. Leaf surface is reduced

and plant vitality is lowered, and lower quality

flowers and smaller corms result.

Cucumber mosaic is manifest by white

streaks in leaves, stripe breaks in flowers, and

short stems. In Northeastern States some infected cultivars are completely destroyed and

eliminated each year by cucumber mosaic virus.

Infection by the stunt virus makes spikes,

plants, and leaves short. Infected plants are a

complete loss because they are too short for the

cut-flower market.

Estimated average annual losses caused by

specific gladiolus diseases for the period 1951-

60 are as follows :

Average

annual

loss

Disease (percent)

Fusarium corm rot 5.0

Stromatinia dry rot 5.0

Botrytis blight 3.0

Cucumber mosaic 2.0

Curvularia blight 2.0

Stunt (virus) 2.0

Stemphylium leaf spot ^-Q -

Total 20.0

Lilies

In the Southeast, where bulbs are produced

for greenhouse finishing as cut blooms, production has been sharply limited by necrotic fleck,

a virus complex transmitted by aphids. Fleckdiseased plants are unsalable because they are

dwarfed and foliage is curled. Flowers are unsalable because they are subnormal in size, fail

to open fully, and are distorted and streaked.

The affected plants produce undersized bulbs

that cannot be sold. Spray costs for controlling

aphids are high, and the frequent replacement

of planting stock from uncontaminated areas

is expensive. The Creole cultivar has practically

disappeared because of fleck.

In the Northwest, where bulbs are grown

for the Easter potted plant trade, scorch, due

to nutritional imbalance, causes tipburn of

leaves of the cultivar Croft. Scorch reduces

bulb yields. A root-rot complex, involving

fungi, nematodes, and symphyllids, causes sen-
34 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

ous losses to Croft. The roots are killed, plants

stunted, leaves scorched, and buds blasted.

The bulb yields of Easter and garden lilies

are reduced by botrytis blight and fusarium

rot. Flowers of the more susceptible lilies, such

as Madonna and Testaceum cultivars, are completely ruined. Botrytis blight is more prevalent in cool, moist weather, whereas fusarium

rot causes losses in warm, moist soils. The

flowering stems are stunted and hence unsalable. Bulbs are rotted and yields reduced.

Scales from diseased bulbs are unsalable for

further propagation.

Estimated average annual losses caused by

speciñc diseases in lilies for the period 1951-60

are as follows :

Average

annual

loss

Disease (percent)

Botrytis blight 4.0

Fusarium rot 4.0

Necrotic fleck (virus complex) 4.0

Scorch 3.0

Total 15.0

Roses

Black spot occurs wherever roses are grown

in humid areas and causes greater losses than

any other rose disease. It causes defoliation

and subsequent dieback and killing, predisposes

the plants to winter killing, and reduces flower

production. Losses are extremely high in home

gardens. In commercial plantings the disease

is controlled at great expense for spray material and labor costs. Rose black spot caused

average annual losses during the period 1951-

60 estimated at 8 percent.

Rose powdery mildew, a common disease in

humid areas, is especially prevalent in greenhouses. Despite consistent spray programs,

yield is reduced by the disease or by the phytotoxic effects of the necessary spray. The leaves

and buds are distorted and the badly affected

flowers are valueless. Affected buds often do

not open. Estimated average annual losses of

4 percent are attributable to this disease.

Shade and ornamental trees

Over 1,000 species and varieties of native and

introduced shade and ornamental trees are

grown in home grounds, on farmsteads, in

parks, and along streets and highways. No

species is immune from disease. A conservative

estimate of trees killed annually by diseases

would be 1 percent. Some disease-producing

organisms kill the trees, some weaken them

so that they are unsafe, and others kill the tops

and reduce growth. Examples of killing diseases and the regions in which they are present

are: Dutch elm disease, the most destructive

shade tree disease in the Northeast and Midwest; elm phloem necrosis and oak wilt in the

Midwest; mimosa wilt in the Southeast; and

cankerstain of London planetree in the Middle

Atlantic States. There are hundreds of canker

diseases, wood rots, leaf diseases, and root diseases of shade and ornamental trees. The total

losses from these diseases in terms of reduced

growth and impaired esthetic value cannot be

estimated accurately on the basis of available

information.

No definite information is available on the

total cost of protecting shade trees from diseases and of replacing those killed or structurally weakened. A conservative estimate of

the average cost of removing one large dead

tree and replacing it with a small tree is $20

to $50. Recently the low bid for tree removal

in one eastern city was $113 per tree. In one

large midwestern city the budget for shade

tree care, mostly control of Dutch elm disease,

was $750,000 in 1961. Bond issues for $2,500,-

000 were passed by one midwestern city for

Dutch elm disease control. Losses from shade

tree diseases are continuous, but in a given

locality may increase greatly for a few years

when an epidemic such as Dutch elm disease

strikes.

CROP LOSSES FROM AIR POLLUTANTS

Plant damage from air pollution was recognized during the past century. The classical

example of damage resulting from such acid

fumes as sulfur dioxide, chlorine, and fluorides

emanating from industrial plants is well known.

During the 1950's a form of air pollution resulting from photochemical reactions in the

atmosphere was recognized in widely separated

parts of the United States. Two important

toxicants identified from these reactions are

ozone and peroxyacetyl nitrate. These compounds result when hydrocarbons and nitrogen

oxides from automobile exhausts and other

combustion sources react in the presence of

sunlight. Photochemical air pollution has been

identified as causing plant injury in 25 States

and the District of Columbia. With increasing

population and industrialization the potential

agricultural damage from this source will undoubtedly increase.

Losses due to various forms of air pollution

are diflîcult to estimate, and only limited reliable data are available. Losses are relatively

easy to estimate when pollution is severe

enough to cause chlorosis or necrosis of leaves

of plants such as lettuce, spinach, and tobacco ;

to injure flowers and ornamental crops such as

orchids enough to reduce their value or make

them unsalable; or to kill the plants. Plant
LOSSES IN AGRICULTURE 35

growth, however, is reduced without visible

injury. Under such conditions damage to crops

is difficult to assay but can be demonstrated by

measurements of growth rates, leaf area, fresh

and dry weights, size and quality of fruit, and

yields. Accumulation of fluorides in forages

and vegetable crops may prevent their use as

feed and food.

In southern California, visible damage to

crops from photochemical air pollution was

estimated at over 3 million dollars in 1953

and over 8 million dollars in 1958. More recently crop losses in California probably

reached 10 million dollars. In Connecticut losses

to the cigar wrapper tobacco crop were estimated at 3 to 5 million dollars in 1955 and

1959. Most of the loss in 1959 occurred on a

single weekend in mid-July. In 1959 truck

crops in New Jersey were damaged by air pollutants. Damage to vegetation in urban and

suburban areas, where it is known that plants

are more likely to be affected, has not been

estimated. Estimates of annual losses to agricultural crops from air pollutants due to growth

suppression, delayed maturity, reduction in

quality, reduction in yields, and other factors

range from 150 million dollars to 500 million

dollars for the period 1951-60, but an average

of 325 million dollars was used in calculating

the total losses due to plant diseases.
Chapter 3.-Nematode Damage to Crop Plants

The gross effects of heavy infection by plantparasitic nematodes are malformation of the

plant parts attacked and interference with their

normal growth and function. Nematode damage is often extended by bacteria and fungi

that invade the damaged tissue and cause general rotting. If enough of the root system on

a plant is damaged, growth of the plant is

limited, and it shows signs of malnutrition and

lack of water. Thus, nematode damage often

reduces growth and yield.

In addition to reducing yield, nematode damage may also reduce the quality of produce.

Root-knot nematodes cause conspicuous galls

on beets, carrots, and potato tubers. The damaged vegetables are discarded as culls at harvest. The wheat nematode causes galls to form

instead of wheat grains; the galls mixed with

the wheat reduce its grade. Fruit from citrus

trees heavily infected by citrus nematodes is

smaller than fruit from normal noninfected

trees. The same is often true of fruit from

other nematode-infected crop plants.

Some species of nematodes transmit diseaseproducing viruses, but their importance in field

spread of viruses cannot be evaluated fully.

However, vineyards from which fan leafinfected grape vines have been removed cannot be replanted with virus-free plants for

several years because nematodes transmit the

virus from infected grape roots remaining in

the ground to the new vines.

Estimating nematode damage in the field is

subject to the variables and complications common to all crop loss estimates plus the difficulty

or impossibility of identifying nematodes except with a microscope. For this reason, nematode damage often escaped notice in the past

or was attributed to some other cause. With

the increasing use of nematocides in experimental work and by growers since 1950, it

has become possible to measure differences in

growth between nematode-infected and nematode-free plants. The best information on the

effects of nematodes on plants has come from

comparisons between the growth of plants on

soil to which a nematocide had been applied

and on adjacent untreated soil. Estimated

average annual losses due to nematodes are

given in table 9 for 18 farm crops widely grown

in the United States. No data are available

for the others or for losses to the multimillion

dollar a year ornamentals and nursery business; leaf nematodes cause estimated annual

losses of 1 percent to the chrysanthemum industry, for example.

FIELD AND FORAGE CROPS

Losses from nematodes have been estimated

for eight field and forage crops : Alfalfa, corn,

cotton, lespedeza, peanuts, soybeans, sugarbeets, and tobacco. The estimated average annual losses caused by nematodes in these eight

crops total $300,041,000 (table 9). Losses for

all field crops would be considerably more.

Alfalfa

Of the nematodes that attack alfalfa, the

best known are the stem nematode, species of

root-lesion nematodes, and several species of

root-knot nematodes. These nematodes have

been reported from all parts of the United

States in which alfalfa is grown. Where alfalfa

is grown in rotation with annual crops, the

root-knot nematodes that increase on alfalfa

may also damage the rotation crop.

Corn

Corn is attacked by several species of rootknot nematodes, sting nematode, stubby-root

nematode, root-lesion nematode, stunt nematode, and others. Nematode damage is often

severe ; in 41 experiments, mostly in the Southern States, the average yield on nematocidetreated plots was 33 percent more than on untreated plots.

Cotton

Cotton is attacked by several kinds of nematodes, of which the best known are the cotton

root-knot nematode and the southern root-knot

nematode. Nematodes occur wherever cotton

is grown in the United States and take a steady

toll year after year. Often associated with

damage from root-knot nematode is fusarium

wilt. Research on the two in combination has

developed nematode- and wilt-resistant varieties. In scattered fields in the Southeast, severe

damage due to sting nematode is not uncommon. Damage to cotton by reniform nematode

has been reported in several locations in

Louisiana.

36
LOSSES IN AGRICULTURE

37

TABLE 9.—Estimated average annual losses to various crops caused by nematodes, and cost of

netnatode control ' ^

Crop group and commodity

Production

unit

Loss from potential production

Reduction '

Field and forage crops :

Alfalfa

Corn

Cotton

Lespedeza

Peanuts

Soybeans

Sugarbeets

Tobacco

Total

Fruit crops :

Lemons

Oranges

Peaches

Raspberries

Total

Ton

BushelBale-__

Pound-

—do

BushelTon

PoundTon

—do

BushelQuart—

Vegetable crops:

Beans:

Green lima

Green snap

Cantaloups

Potatoes

Tomatoes :

Fresh market _.

Processing

Total

Hundredweight

—do

—do

_^do

—do

Ton _

Total, all crop groups

Cost of controlling nematodes

Grand total

Percent

5

5

5

4

8

8

Quantity

1,000 units

2,195

103,263

310

4,109

53,544

9,179

605

66,382

26

229

2,826

23,618

131

646

647

9,484

1,728

333

Value

1,000 dollars

48,581

131,821

50,153

457

5,755

20,405

6,814

36,055

300,041

1,782

12,853

5,658

4,134

24,427

961

4,413

2,852

18,848

12,114

8,679

47,867

372,335

16,000

388,335

1 See table 2, footnote 1. See table 2, footnote 2.

Lespedeza

In all parts of the country where it is grown,

lespedeza is attacked by a variety of nematodes.

In the Southeast, damage due to attacks by

various species of root-knot nematodes is often

very severe, and root-knot nematodes that increase on lespedeza injure crops grown in rotation with it. Lespedeza is also reported as

a good host of the stubby-root nematode, the

soybean cyst nematode, and the recently discovered lespedeza cyst nematode.

Peanufs

Wherever peanuts are grown, they are subject to attack by two species of root-knot nematodes, by the root-lesion nematode, and in the

sandy soils of the Southern Coastal Plain by

the sting nematode. Damage from a heavy

infestation of any one of these can be severe;

reductions in yield of more than 50 percent are

not uncommon. The damage is due partly to

reduced yields because of root damage and

partly to loss of pods because of rotting of the

stems. Often root-lesion nematodes invade the

shells and cause brown lesions, which reduce

the grade. Brown lesions are particularly serious on peanuts sold in the shell.

Soybeans

Soybeans in the Southeastern States are

widely attacked by the southern root-knot

nematode and the cotton root-knot nematode;

in the States north of the Ohio River by northern root-knot nematodes. In all parts of the

United States soybeans are attacked by various species of root-lesion nematodes. The soybean cyst nematode has been found infesting

about 70,000 acres of soybeans in parts of

eight States. Where the soil is heavily infested

by any of these nematodes, yields of soybeans

are reduced. The best information on reduction of yield by nematodes is available for the

soybean cyst nematode. In sandy soils of the

Coastal Plain in North Carolina, it can reduce

yields as much as 75 percent. In the Mississippi

Valley, yield reductions of 30 percent have been

reported.
38 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

Sugarbeets

The nematode of most concern to sugarbeet

growers is the sugarbeet nematode. It has been

found in nearly all sugarbeet-growing regions

of the United States. In some locations it is

a major pest. In addition, sugarbeets are attacked by several species of root-knot nematodes ; they are a serious problem in California.

In Colorado, Nebraska, and Wyoming, sugarbeets are attacked by the hairy-gall nematode.

Reductions in yield often amount to more than

50 percent.

Tobacco

Probably the data on reduction of yields of

tobacco in the Carolinas, Florida, Georgia, and

Virginia are the best-documented information

available on damage due to nematodes. The

nematodes most common on tobacco in these

States are species of root-knot nematodes

(mostly cotton root-knot nematodes), tobacco

stunt nematode, and species of root-lesion

nematodes. All these nematodes damage the

root systems and reduce yields. In 151 experiments, mostly in North Carolina, yield reductions averaged 13 percent with reductions of

30 to 50 percent in some fields.

FRUIT CROPS

Losses from nematodes have been estimated

for four fruit crops : Lemons, oranges, peaches,

and raspberries. The estimated average annual

losses caused by nematodes in these four crops

total $24,427,000 (table 9). Loss data for other

fruit crops and for nut crops are not available.

Citrus fruits

The best known nematode pest of citrus in all

citrus-growing regions of the United States is

the citrus nematode. It is said to infect 95 percent of citrus trees in CaHfornia and is known

to occur on a considerable proportion of citrus

trees in other parts of the United States. In

Florida, an intensive survey indicated that

several thousand acres of citrus are infected by

the burrowing nematode. In addition, species

of root-lesion nematodes, sting nematode, and

others are widely distributed on citrus. Nematodes attack the feeder roots and initiate rots,

which are extended by bacteria and fungi. If

enough roots are damaged, the tree declines.

Leaves may be abnormally small and have poor

color; twigs without leaves appear at the top

of the tree ; and fruit production declines, partly

because of decreased size of the fruit. Extensive data are not available, but where citrus

nematodes were controlled in producing citrus

groves in Arizona, yields were increased an

average of 25 percent. In similar experiments

in California, yield increases of about 20 percent were reported.

Peaches

Peaches in Southeastern United States and

California are often attacked by root-knot

nematodes (mostly cotton root-knot and

Javanese root-knot nematodes). The root system is distorted and reduced by heavy infections, and the tree grows and produces poorly.

In only a few experiments could nematode-infected and nematode-free trees be compared.

In these experiments, yields from the nematodefree trees were 50 percent or more higher than

from the nematode-infected trees.

Raspberries

The principal nematode pests of raspberries

are the root-lesion nematodes, found wherever

raspberries are grown in the United States.

Root-lesion nematodes destroy cells of the root

cortex and lead to general root rot if the damage is extended by bacteria and fungi.

VEGETABLE CROPS

Losses from nematodes have been estimated

for six vegetable crops : green lima beans, green

snap beans, cantaloups, potatoes, tomatoes for

fresh market, and tomatoes for processing. The

estimated average annual losses caused by

nematodes in these six crops total $47,867,000

(table 9). The total for all vegetable crops

cannot be estimated because data are lacking.

Beans

Green lima and snap beans are attacked by

various species of root-knot nematodes in the

Southern States. These nematodes cause root

damage, which reduces growth and yield.

Losses range from negligible to as much as 75

percent.

Cantaloups

In the warmer parts of the country cantaloups are often heavily infected and seriously

injured by several species of root-knot nematodes. Heavily attacked plants have much reduced and thinned root systems and grow and

produce poorly. In 17 experiments in the

Southeast, cantaloups infected with root-knot

nematodes produced 33 percent less than plants

on adjacent plots treated with nematocides.

Potatoes

Potato roots and tubers are attacked by

various nematode species, of which the most

important are root-knot nematodes, root-lesion

nematodes, the golden nematode, and the potatorot nematode. Attack on the roots reduces yield.

Invasion of the tubers by root-knot nematodes
LOSSES IN AGRICULTURE 39

causes formation of knots; root-lesion nematodes cause dark-colored, partly decayed spots

on the surface of the tubers; and potato-rot

nematodes cause internal rotting. In fields

heavily infested by nematodes, yields are low

and there are many culls. In 14 experiments

in Idaho, Nevada, New York, and Ohio, the

average yield on nematocide-treated plots was

75 percent more than on untreated plots.

Root-knot nematodes are found in all parts

of the United States where potatoes are grown.

In the Northern States, the species is almost

invariably the northern root-knot nematode;

in the Southern States, it may be the cotton

root-knot nematode or another species. Rootlesion nematodes are also widely distributed in

the potato-growing regions of the United

States. The golden nematode has been found

in the United States on only about 13,000 acres

on Long Island, N.Y. Over half of this area has

been sold for real estate development and is no

longer used for farming; the remainder is

under strict quarantine. The potato-rot nematode has been found in potato fields in Idaho

and Wisconsin, where strenuous efforts are being made to exterminate it.

Tomatoes

Probably the most important nematode

parasites of tomato are various species of rootknot nematodes, which are widely distributed

over the United States. Heavy infections of

cotton root-knot nematodes are common in the

warmer parts of the country. In the North, the

northern root-knot nematode is the species

generally found. All root-knot nematode species

cause galling of the roots, which interferes

with their efficiency. If a large portion of the

root system is affected, the plant grows and

produces poorly. In 64 experiments reported

from Arizona, California, and Georgia, the

average increase in yield on plots where nematocides were used was 72 percent more than on

adjacent untreated plots.
Chapter 4-Injurious Crop Insects

According to the Yearbook of Agriculture

for 1952, approximately 10,000 species of insects in the United States are important enough

to be called public enemies. About four-fifths

of them are injurious to crops. They reduce

the yield, lower the quality, contaminate the

marketed product, and increase the cost of

producing, processing, and marketing the crop.

Many species, however, are limited in distribution and cause only occasional damage.

Estimates of the losses caused by insects in

this country have been assembled by different

workers at various times, but no adequate basis

is available for estimating the total loss by all

destructive species. Estimates that have been

made concern only a few species, chiefly those

of major economic importance. Persons attempting to develop estimates soon find that

many variables and complicating factors make

the task a formidable one. For instance, the

crop damage caused by one species differs from

year to year and from one area to another.

Furthermore, most insects of economic importance tend to appear in cycles of abundance.

Some of them inflict heavy losses each year

while others cause little or fairly uniform damage for several years, followed by an upsurge

of damage when they reach outbreak proportions.

Insect losses to many crops in any one year

differ greatly from those of a few years

earlier. Some pests, particularly those not native to this country, have spread to new areas

and have thus extended their damage. Examples are the spotted alfalfa aphid, the cereal

leaf beetle, and the face fly. Other insects have

modified their habits and have become pests of

economic importance on crops not previously

attacked. For example, the green peach aphid

did not become an important problem on

tobacco until about 1946.

Changing agricultural conditions and practices also affect insect losses. In 1935, the

tomato pinworm was a major pest of the

tomato crop in southern California. This insect has become of minor importance chiefly

because of changes in cultural practices that

involve destruction of crop remnants. The development of new insecticides has appreciably

changed the situation with respect to many

insects. The chlorinated hydrocarbon, organic

phosphorus, and carbamate insecticides have,

for the first time, made it practicable to control

insects on some crops. But along with their

widespread use have come such complicating

problems as the resistance of certain pests to

some of the materials that at first provided good

control, and the hazards of insecticides and

their residues to man and animals.

Estimates of losses for selected insects attacking field, forage, seed, fruit, nut, vegetable,

and horticultural specialty crops are given in

tables 10 to 15. Included also are estimates of

losses caused by insects to turf, landscape

flowers and ornamentals, and the honey bee

industry. Altogether these losses total $3,812,

906,000.

The average annual losses in value for the

various crop groups during production, and for

honey bees, are shown in table 10. Insects other

than those included in these estimates cause

considerable losses to crops grown in the

United States. However, with available data,

dependable estimates of these additional crop

losses cannot be made.

Insects, including aphids, beetles, grasshoppers, leafhoppers, and thrips, are known as

vectors of many viruses that infect cultivated

crops and cause heavy losses. Such crop losses,

for which insect vectors of plant diseases share

an important part of the responsibility, are

considered in chapter 2. The following examples illustrate the importance of insect

vectors of plant diseases.

TABLE 10.—Estimated average annual losses

caused by insect pests to various groups of

crops and to honey bees, 1951-60

Crop group Average annual loss

1,000 dollars

Field crops 1,482,325

Forage crops (alfalfa) 242,905

Seed crops 25,927

Rangelands 80,000

Turf 827,000

Fruit and nut crops 121,295

Vegetable crops 185^892

Landscape flowers and

ornamentals 7^8 000

Horticultural specialties 79062

Honey bees '500

Total 13,812,906

1 For cost of controlling crop insects, see table 51.

40
LOSSES IN AGRICULTURE

Aphids are responsible for transmitting infection of yellows viruses to sugarbeets in

Arizona, California, and Washington, and to

strawberries in Washington and most other

States; and they carry cucumber mosaic and

watermelon mosaic to cantaloup and other

melons. In Arizona and California these insects transmit lettuce mosaic, and in the Pacific

Northwest they also carry the iris mosaic of

bulbous iris, the tulip mosaic of tulips, the

narcissus mosaic of narcissus, and the necrotic

fleck of Easter lily bulbs. Aphids are also vectors of sugarcane mosaic in Florida and

Louisiana, and of barley yellow dwarf of small

grains throughout the United States.

In Eastern United States aphids transmit

aspermy virus from infected chrysanthemums

to tomatoes and are vectors of dahlia and

narcissus mosaic. The green peach aphid is a

vector of more than 50 kinds of plant viruses,

including several that infect potatoes and cause

severe losses to that crop.

The beet leafhopper transmits the curly top

virus to beans, cucumbers, pumpkins, squashes,

sugarbeets, and tomatoes in Western United

States. The plum leafhopper carries peach

yellows to peach trees, and other leafhoppers

are vectors of phony peach and other diseases

of peach. In Kansas and neighboring States,

the wheat curl mite transmits wheat streak

mosaic, a serious virus disease of wheat.

The six-spotted leafhopper is responsible for

introducing into the Eastern States the western

strain of aster yellows, which infects dahlia,

zinnia, carrots, and celery in New Jersey and

41

New York. Losses from aster yellows tran^

mitted by the leafhopper to lettuce we^^^^^^^^^^

severe m western Maryland and southwestern

Pennsylvania that production of the croD in

that area had to be discontinued.

Three species of cucumber beetles transmit

squash mosaic to squash and bacterial wilt to

cucurbits in eastern vegetable-growing areasand corn flea beetles spread bacterial wilt in

sweet corn.

Insects also transmit plant diseases to alfalfa

clover, lupines, citrus, elm, grapes, onions!

tobacco, and other plants, and additional instances of the insect vector-plant disease relation will likely be discovered.

FIELD CROPS

As indicated in table 11, estimated average

annual losses caused by insects to field crops are

$1,482,325,000.

Corn ancf sorghum

Corn rootworms (northern, southern, and

western) are very destructive to corn. Although

these insects are present throughout most of

the Corn Belt, they are most serious in Iowa,

Kansas, Minnesota, Nebraska, South Dakota,

and Wisconsin, where they have developed resistance to previously recommended insecticides. Larvae of the rootworms feed on the

roots of the corn plants, causing the plants to

lodge and reducing crop yield.

The corn earworm is a most destructive

enemy of field corn, sweet corn, and popcorn.

In addition, it infests alfalfa, cotton, peanuts,.

TABLE 11.--FIELD CROPS : Estimated average annual losses due to insects, 1951-60

Production

unit

Loss from potential production i

Commodity Reduction 2 Quantity Value

Barley Bushel

Beans, dry HundredweightCorn Bushel

Cotton Bale

Hops Pound

Mint 3 do

Oats Bushel

Peanuts Pound

Peas, dry HundredweightRice - -do

Sorghum (grain) Bushel

Soybeans do

Sugarbeets Ton

Sugarcane —do

Tobacco Pound

Wheat Bushel

TotaL

Percent

5

20

12

19

15

15

4

3

6

4

9

3

12

15

11

6

1,000 units

20,177

4,027

413,051

2,943

8,140

468

57,006

53,544

229

2,214

33,866

13,768

1,815

1,243

243,355

74,533

lyOOO dollars

19,787

29,335

527,285

476,457

3,829

2,211

37,794

5,755

1,030

10,742

34,072

30,607

20,441

8,818

132,179

141,983

1,482,325

1 See table 2, footnote 1.

2 See table 2, footnote 2.

3 Peppermint and spearmint.
42 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

sorghums, soybeans, tobacco, and vetch, and

tomatoes and other vegetable crops. Larvae

of the corn earworm feed on the buds or central

shoots of young corn plants, stunting them and

reducing the yield. Later the worms go down

through the silks of the ears and destroy many

of the kernels. Sometimes they chew off the

silks and prevent pollination. Their feeding

in the ears also allows molds to enter, which

increases the total damage.

The European corn borer is one of the most

injurious pests of field and sweet corn in the

United States. Discovered in Massachusetts and

New York in 1917, the corn borer has spread

westward until it now infests the entire Corn

Belt ; it reaches to the eastern edges of Colorado

and Montana, and occurs southward as far as

Alabama, Arkansas, Georgia, Louisiana,

northern Mississippi, northeastern Oklahoma,

and South Carolina. The European corn borer

reduces the yield and increases the cost of harvesting by causing broken stalks, poor ear development, and dropped ears. Maximum damage by this insect occurred in 1954, when losses

to field corn were estimated at $261,415,000.

The southwestern corn borer is a pest of corn

in parts of Arizona, Arkansas, Colorado,

Kansas, New Mexico, Oklahoma, and Texas, and

in a few counties in Alabama, Louisiana,

Mississippi, Missouri, and Tennessee. The

larvae feed on the leaves of the young corn

plants, and retard their growth. The larvae

also damage the ears and girdle and tunnel the

stalks. This damage weakens, stunts, and

sometimes kills the plants. The girdling and

tunneling in the lower part of the stalks in the

fall cause many plants to fall over, and their

ears are lost at harvesttime.

Chinch bugs, corn earworm, sorghum midge,

and sorghum webworm may cause severe injury to grain sorghums. Insects that do less

damage to grain sorghums include the corn leaf

aphid, cutworms and armyworms, and the

southwestern corn borer.

Estimated average annual losses in yield

of corn and grain sorghums caused by specific

insects for the period 1951-60 are as follows :

Average

annual

loss

Crop and insect (percent)

Corn : ^

Corn earworm ^-^

European com borer 3.5

Corn rootworms 2.1

Grasshoppers »^

Fall armyworms -5

Corn leaf aphid -4

Chinch buff -^

Southwestern corn borer .2

Other insects iL

Total IM.

Average

annual

loss

Crop and insect (percent)

Grain sorghums:

Corn earworm ^-j

Sorghum webworm j--^

Chinch bug j-^

Sorghum midge J-¿

Cutworms and armyworms •&

Com leaf aphid -4

Southwestern corn borer -2

Total 9.0

Cotton

The boll weevil reduces cotton yields more

than any other pest. Seventy-eight percent of

the cotton acreage in the United States is infested with this insect. The boll weevil occurs

where cotton is grown from the eastern twothirds of Oklahoma and Texas east to the

Atlantic Ocean. Damage varies between States

and between years. The adult weevils puncture

the cotton squares and bolls and the females

lay their eggs in them. Larvae develop inside

the fruiting forms. Many of the punctured

squares and small bolls are shed by the plants.

Infested large bolls that remain on the plant

often produce no cotton, or only a little of inferior quality.

The boUworm and tobacco budworm, two

closely related pests, reduce cotton yields. The

adult moths lay their eggs on the tender grovd:h

of cotton plants and the larvae hatching from

them feed on the squares and bolls. Damage

often occurs so late in the season that the plants

do not have time to mature another crop of

bolls. The bollworm usually causes its greatest

damage in the Southwest and West.

Lygus bugs are major pests of cotton in the

West; in the Southwest the cotton fleahopper

ranks after the boll weevil and bollworm as a

serious pest. These and other hemipterous insects injure the cotton plant by feeding on the

juices from the tender parts.

Appreciable reduction in cotton yield can be

attributed to the beet armyworm, cabbage

looper, cotton aphid, cotton leaf perforator, cotton leafworm, pink bollworm, spider mites,

thrips, and other insects that sometimes attack

cotton. The cotton leaf perforator is of major

economic importance in the West, and thrips

cause considerable damage in several areas.

Infestations by some of these pests are sporadic

and considerable damage is frequently inflicted

to the crop before growers realize the need for

control measures.

Estimated average annual losses in yield of

cotton caused by insects for the period 1951-60

are as follows :
LOSSES IN AGRICULTURE

43

Average

annual

loss

Insect (percent)

Boll weevil 8.0

Bollworms 4.0

Lygus bugs, cotton fleahopper, and other

sucking insects 3.4

Thrips, spider mites, cotton aphid, cabbage

looper, cotton leaf perforator, pink bollworm,

beet armyworm, cotton leafworm, and other

insects 3.6

Total 19.0

Hops

Spider mites adversely affect the yield and

quality of hops by puncturing the lower leaf

surfaces and withdrawing the plant sap. The

hop aphid also feeds on the plant sap, reducing the yield of the harvested crop and lowering its quality by contamination with insect

fragments and excrement. The corn earworm,

the hop butterfly, the hop looper, and various

cutworms and armyworms chew the foliage;

and cucumber beetles, the garden symphylan,

root weevils, white grubs, and wireworms feed

on the roots of hops.

Estimated average annual losses in yield of

hops caused by insects for the period 1951-60

are as follows:

Average

annual

loss

Insect (percent)

Spider mites 6.0

Aphids 4.0

Other insects 5.0

Total 15.0

Mint

The two-spotted spider mite is the most

widely distributed pest of peppermint and

spearmint, and causes greatest losses to the

crop. The cabbage looper, the mint looper, and

various cutworms feed on the leaves of mint

plants and are especially destructive in the

Midwest. Aphids and the mint flea beetle also

feed on the leaves, especially in the Northwest.

Root weevils and the garden symphylan commonly attack the roots of the plants, and losses

from these insects may accumulate before their

damage is recognized.

Estimated average annual losses in yield of

mint caused by specific insects for the period

1951-60 are as follows :

Average

annual

Peanuts

The southern corn rootworm annually de

stroys an appreciable quantity of field-cured

peanuts grown on heavy soils in the VirginiaNorth Carolina area. The larvae bore into the

pods and feed on the developing kernels The

velvetbean caterpillar has sporadically ' damaged severely and sometimes destroyed peanut

plantings. Cutworms, leafhoppers, the rednecked peanut worm, thrips, and white-fringed

beetles are destructive pests of peanuts in

some areas in certain years.

Estimated average annual losses in yield of

peanuts caused by insects for the period 1951-

60 are as follows :

Average

annual

Insect (percent)

Spider mites 7.0

Caterpillars and flea beetles 4.7

Soil insects 2.1

Aphids 1.2

Total 15.0

Insect (percent)

Southern corn rootworm 0.8

Leafhoppers, thrips, red-necked peanut worm,

white-fringed beetles, cutworms, and

velvetbean caterpillar 2.2

Total "3:0"

Small grains

Greenbugs frequently cause extensive losses

to barley, oats, and wheat in various parts of

the Great Plains from Texas north to Canada.

However, in some years they do little damage.

The hessian fly is one of the most destructive

insect enemies of wheat in the United States.

It is distributed over the North Central and

Northeastern States, a portion of the Southern

States, and within limited areas in California,

Oregon, and Washington. Local outbreaks

occur nearly every year, and widespread damage can be expected at irregular intervals, sometimes as often as every 5 or 6 years. In the fall,

the fly maggots suck the juices of the young

plants, killing them outright or weakening

them so that they cannot survive the winter.

In the spring, they kill the plants in the same

way ; later in the season, they cause the stems

to break so that the heads are missed by the

harvesting machinery.

The wheat stem sawfly is a destructive pest

of wheat in northern North Dakota and

Montana. It is a pest of native grasses that

has found wheat a favorable host. In 1951,

loss by the sawfly in North Dakota and Montana

was estimated at 4,918,484 bushels of wheat

worth approximately $10 million. Damage by

the insect in bordering States has been much

less severe. Losses result from reduced weight

of the wheat kernels caused by tunneling of the

stems of wheat by the sawfly larvae, and the

breaking over of stems girdled by the insect.

When the stems are broken, the wheat heads

cannot be recovered during harvesting.
44 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

Estimated average annual losses in yield of

small grains caused by specific insect pests

during the period 1951-60 are as follows :

Average

annual

Grain and insect (percent)

Barley:

Cutworms 2.8

Greenbug 1.9

Brown wheat mite .3

Total 5.0

Oats:

Greenbug 2.3

Cutworms 1.4

Brown wheat mite .3

Total To"

Wheat:

Greenbug 1.4

Hessian fly 1.2

Wheat stem sawüy 1.0

Cutworms .9

Armyworm .6

Brown wheat mite .5

Grasshoppers .4

Total 6.0

Rice

The two most important pests of rice are

the rice stink bug and the rice water weevil.

Most of the damage by the rice stink bug is

caused by the nymphs, which suck the juice of

the developing kernels and cause pecky rice.

The adults of the rice water weevil feed on the

newly emerged rice plants, and the larvae

severely injure the roots.

Estimated average annual losses in yield of

rice caused by these insects for the period 1951-

60 are as follows :

Average

annual

loss

Insect (percent)

Rice stink bug 3.0

Rice water weevil 1.0

Total 4.0

Soybeans

Damage to soybeans is caused by the bean leaf

weevil, garden fleahopper, Mexican bean beetle,

mites,'stink bugs, and velvetbean caterpillar.

Feeding by stink bugs lowers the market

quality of the beans.

Sugarbeets

Sugarbeets grown for seed in the Western

States are planted in the fall and harvested

the following summer. Caterpillars of various

kinds attack the seedling plants. The beet leafhopper also feeds on the seedlings but, more

important, it is the vector of curly top, a very

destructive disease of sugarbeets.

In the spring, the seed crop is damaged by

seed-feeding insects, primarily lygus bugs and

stink bugs, in spite of control measures. Outbreaks of the Say stink bug are rare but cause

very severe damage to the crop when they do

occur. Spider mites and aphids also feed on the

foliage and flower buds and cause a direct

reduction in yield of seed. However, the primary damage by aphids is the spread of the

virus diseases of beet yellows and beet Western

yellows. These diseases result in heavy losses

to the crop.

On the sugarbeet crop grown for sugar,

major damage is caused by armyworms, the

beet webworm, and other caterpillars, and by

spider mites—all of which feed on the foliage ;

by root aphids, root maggots, symphylans, and

wireworms attacking the roots ; and, indirectly,

by aphids and leafhoppers transmitting virus

diseases.

Sugarcane

The sugarcane borer is the most injurious

insect attacking sugarcane grown for sugar

and seed in the United States. Estimates of loss

by this insect in Florida and Louisiana are

based on the percentage of bored sugarcane

joints found in annual harvesttime surveys.

In addition, the insect attacks corn, rice, and

sorghums, causing large additional losses.

Young larvae of the sugarcane borer bore into

young plants, destroying the central tissues and

causing dead hearts. In older plants, the

borers attack the tops of the plants, causing

them to die ; and they tunnel in the stalks, weakening them so that they break over. Tunneling

by the borer also causes a loss in weight and

sucrose content and injures seed cane.

Estimated average annual losses in yield of

sugarcane caused by speciñc insects for the

period 1951-60 are as follows :

Average

annual

loss

Insect (percent)

Sugarcane borer 12.1

Soil insects i[g

Aphids i\

Total I~I"_"_ ïtô

Tobacco

Tobacco budworms and hornworms can destroy entire fields of tobacco. When severe

damage is anticipated, growers apply insecticides several times during the growing season

to reduce losses. North Carolina growers controlled light infestations of these insects in

1957 and 1958, and lowered the potential losses

of flue-cured tobacco from about $36 to $5 per

acre.
LOSSES IN AGRICULTURE

The green peach aphid is the most destructive insect of the tobacco crop in Kentucky and

Maryland, and is particularly damaging to the

shade-grown tobacco of Connecticut and

Florida. Three other insect pests of tobacco—

the cabbage looper, the southern potato wireworm, and the tobacco flea beetle—have developed resistance to insecticides that had

formerly controlled them.

FORAGE AND SEED CROPS AND

RANGELANDS

As indicated in table 12, the estimated average annual losses to alfalfa for forage from insect damage are $242,905,000. The annual

losses caused by insects to seed crops are estimated at $25,927,000. Grasshoppers caused

estimated annual losses of $80,000,000 to

rangelands.

Alfalfa, clover, and other forage crops

Insects cause heavy losses to legume and

grass forage and seed crops in many areas of

the United States. However, the data required

to satisfactorily estimate annual losses caused

by a number of these pests are either inadequate

or unavailable.

The alfalfa weevil, for many years a serious

pest of alfalfa in the West, was found in Maryland in 1951. It has spread into 21 Eastern

States where it has caused extensive losses,

especially to ñrst-cutting alfalfa. Larvae of this

insect skeletonize the leaves of the plants, lowering hay yield and quality. High populations

may cause a complete loss of first-crop hay,

and so weaken the stand that some plants do

not survive. Although thousands of acres of

alfalfa are treated with insecticides each year

to control the alfalfa weevil, the pest still de45

The spotted alfa^^^^ aphid since its discovery

^^ ^^? United States m 1954 has become a pest

of alfalfa grown m 33 States across the

southern two-thirds of the country. Heavy dam

age IS confined mainly to areas from Nebraska

southwest to southern California. In 1955-57

this insect caused losses of more than $80

million to alfalfa. Chemical control, parasites

and predators, and resistant varieties of alfalfa

have reduced the damage. Even so, the spotted

alfalfa aphid caused estimated losses of

$1,929,000 to alfalfa in California alone in

1960, where an additional $1,303,000 was spent

for its control. Adults and nymphs of the

spotted alfalfa aphid suck the plant juices,

causing stunted plants, leaf drop, reduced

yields, and plant kill. The insects secrete large

amounts of honey dew on which a black mold

develops. The mold lowers the quality of the

hay.

The meadow spittlebug causes appreciable

losses to alfalfa, red clover, and other legumes.

Feeding by the nymphs of this insect results in

a stunted, rosetted plant growth that often

reduces forage yields 50 percent or more. The

increased use of insecticides to control the

alfalfa weevil in the Eastern Coast States has

reduced the damage caused by the spittlebug to

alfalfa in much of this area.

Lygus bugs suck the juices from buds and

flowers of alfalfa, causing blasted buds and

flower drop. They also puncture the developing seeds and thus lower their quality. Modern

insecticides have been very effective in controlling lygus bugs. However, in many areas

these insects have developed resistance to certain chemicals and are becoming more serious

pests of alfalfa.

TABLE 12.—FORAGE, SEED CROPS, AND RANGELANDS : Estimated average annual losses due to

insects, 1951-60

Commodity

Production

unit

Loss from potential production

Reduction 2 Quantity Value

Alfalfa for forage Ton

Seed crops:

Alfalfa PoundCrimson clover do

Red clover do

Ladino do

Sugarbeets do

Total

Rangelands: Pasture grass and other forage4

Total: Forage, seed crops, and rangelands

Percent

15

38

15

15

17

10

1,000 units

10,976

75,676

3,113

15,515

1,265

3 980

IfiOO dollars

242,905

20,060

639

4,239

842

3 147

268,832

80,000

348,832

1 See table 2, footnote 1.

2 See table 2, footnote 2.

3 Based on data from the 1959 Census of Agriculture.

4 Losses caused by grasshoppers.
46 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

The alfalfa seed chalcid caused losses of 20 to Rangelands

40 percent of the alfalfa seed grown in certain About 20 species of grasshoppers are especiareas 0Î Oaliiornia m 1960. Annual losses due ally destructive to rangelands in the West,

to this pest m the Western States frequently where they consume large quantities of forage

average 10 percent. It is estimated that the that would otherwise support valuable livestock,

clover seed chalcid does about half as much Estimated overall losses on Federal-State and

damage to clover seed. Larvae of these pests private rangelands in 17 Western States

feed within and destroy the developing embryo, amount to approximately $80,000,000 annually,

leaving only the hollow shell.

The potato leafhopper sucks the plant juices TURF

and causes extensive losses to alfalfa and red

clover each year in the eastern half of the The production of turf and the maintenance

United States. Losses of one-fourth to one- of lawns, golf courses, and other turf areas

half ton of hay per acre on second and third ]^ ^^f United States represent a considerable

cuttings are not uncommon. In addition, the investment Insect pests attack all types of

protein and carotene content of the hay is re- f^^J^^, ""aÏTeaT? Terœnt tVt^

duced. Stands are weakened so that many about $827 000 00^^ percent to turi areas, or

plants do not survive the winter. ' '

Other insects of legume and grass crops de- rr^iM^ A...»^ K.I.^ ^ ^ rstroy millions of dollars' worth of seed and FRUIT AND NUT CROPS

forage every year. The more important of these Average annual losses caused to fruit and

pests are the clover aphid, clover leaf weevil, ^ut crops by insects are estimated at $121,295,-

clover root borer, clover seed midge, clover OOO (table 13).

seed weevils, vetch bruchid, chinch bugs, cutworms and armyworms, red harvester ant, Apples

scale insects stink bugs, thrips, webworms, ^.^^^^^ ^^^^^^^ ^^^^^^^^ ^^^ ^pp^^ ^^^p

ana wmie gruDs. .^4.^^^„,^^ ,-^c,nnf would be almost a total loss because of attack

The European chafer, an introduced insect ^ .^^^^^ principally the codling moth, several

distributed^ only m a limited portion of New ^p^^^^g ^f ^pj^i^g^ 1^^^ ^^^^^^^ ^^¿ g^^l^ j^^^^^g

York and m small local areas m Connecticut, nationally; the apple maggot in the NorthNew Jersey, and West Virginia, infests eastern and Great Lakes States; and the plum

meadows, pastures, winter grains, and legumes, curculio in all States east of Nebraska. In reas well as lawns and other turf areas. Damage cent years losses in commercial orchards have

is due entirely to the feeding of the grubs on been held to a low level by the general applicathe roots of the host plants, and occurs annually tion of effective insecticide programs. Insect

once an infestation becomes well established. losses to apples in backyard and farmstead

Estimated average annual losses by specific plantings are estimated to be high since few

insects are given only for alfalfa for hay and such plantings are sprayed adequately and

alfalfa for seed. For the period 1951-60, they many are not sprayed at all.

are as follows • beveral leaf-feeding mites occur on apples

Average in all producing areas; they reduce fruit bud

annual formation, fruit set, leaf chlorophyll, and fruit

.Jfjf.. color and size, and they cause premature drop- Crop and insect (percent) p.^^ ^^ ^^^j^ Outbreaks are more likely to

^^^ SpÄ &fa aphid 4.9 f^^^.^^ Orchards that are otherwise well cared

Potato leafhopper 3.1 for than m orchards that are poorly cared for

Alfalfa weevil 2.5 or uncared for. Even 10 percent of foliage

Pea aphid 2.4 injury has reduced the color of the fruit as

MeÄ^TttleTuT:^ :8 ^^^eh as 20 percent and also fruit size. In the

Garden webworm .2 absence of adequate control measures for mites

Alfalfa caterpillar >i in orchards that are otherwise well cared for.

Total 15.0 yields may be reduced by from one-third to

Alfalfa for seed: two-thirds. However, neglect of mite control

Lygusbugs 24.4 involves Only a small percentage of the total

Alfalfa seed chalcid 10.5 commercial acreage.

GÄopteS'!i:::::::::::::::::::::: ':7 , Losse\caused to apples during the period

Spotted alfalfa aphid _^ 1951-60 by all msects are estimated at 6 perTotal 38.0 cent and by all mites at 7 percent.
LOSSES IN AGRICULTURE 47

TABLE 13.—FRUIT AND NUT CROPS : Estimated average anrnuil losses due to insects, 195i-eo

Commodity

Production

"unit

Loss from potential production i

Reduction 2

Apples

Blackberries

Cherries

Grapes, fresh

Grapefruit

Lemons

Oranges

Peaches

Pears

Pecans

Plums

Prunes, fresh

Raspberries

Strawberries

Miscellaneous fruits and vegetablesTotal

BushelQuart—

Ton

—do

_-do___

_-do-__

—do___

Bushel-

—do

PoundTon

—do

QuartPoundPercent

13

31

3

4

5

6

6

4

6

12

6

6

23

25

Quantity Value

1,000 units 1,000 dollars

15,620 28,910

10,183 1,342

7 1,544

142 7,172

87 2,549

39 2,673

343 19,280

2,826 5,658

1,973 3,592

22,860 5,693

6 967

29 2,937

3 11,164 3 3,142

4 147,612 4 25,836

5 10,000

121,295

1 See table 2, footnote 1.

2 See table 2, footnote 2.

3 Based on data from the 1959 Census of Agriculture.

4 Basic data represent quantity marketed and value

of quantity marketed.

5 Damage by Japanese beetles.

Bramblebernes

A large number of insects and mites frequently cause important losses to blackberries,

boysenberries, dewberries, loganberries, raspberries, and youngberries. In the Northwest

the redberry mite feeds on the green fruits of

blackberry and prevents them from ripening

properly. The raspberry fruitworm feeds within the fruits of the raspberry and blackberry

and, unless controlled, may contaminate the

harvested product. The garden symphylan eats

the roots of the plants, and other insects bore

into the canes and crowns.

Cherries

Cherries are less subject to severe insect

damage than most other tree fruits; however,

in the area east of the Rocky Mountains, the

plum curculio at times injures a high percentage of the crop on unsprayed trees. Heavy

losses are also caused by the black cherry aphid,

cherry fruit fly, cherry fruitworm, eye-spotted

bud moth, leaf rollers, mites, peach twig borer,

tree borers, and scale insects. The presence of

cherry fruit fly infestation can result in condemnation for canning of the entire crop in an

orchard. In general, growers who apply recommended control measures thoroughly and

on schedule suffer no appreciable loss; others

may lose from 5 percent to nearly the total

crop.

Citrus (grapefruit, lemons, and oranges)

Mites, scale insects, thrips, and aphids are

the major pests of citrus. They seriously affect

the vigor of trees and set of fruit and reduce

the quality and grade of fruit. Heavy infestations may restrict tree growth and thus lower

productiveness for extended periods after control has been achieved.

The Mexican fruit fly annually migrates

across the Mexican border into citrus areas in

the lower Rio Grande Valley in Texas where its

presence creates a regulatory problem. Only

rarely are larval infestations found, and these

seldom reach 10 percent in fruits on infested

properties. The oriental fruit fly may cause

serious damage to occasional citrus trees in

home gardens and to the limited commercial

plantings in Hawaii.

Estimated average annual losses caused to

citrus fruits by specific insects for the period

1951-60 are as follows :

Average

annual

loss

Citrus fruit and insect (percent)

Grapefruit:

Mites ^'l

Scale insects ^'n

Other than mites and scales —:£.

Total J4

Lemons: ^A

Mites ^'l

Scale insects ^'^

Other than mites and scales _ii5L

Total J4

Oranges: ^„

Mites 25

Scale insects 'o

Other than mites and scales —:£-

Total ^'^
48 AGKICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

Crapes

Grapes are subject to damage by a variety

of insects ; in the West, most commonly by the

grape leaf folder, leafhoppers, mites, and

pomace flies; and in the East, usually by the

grape berry moth, grape flea beetle, grape

mealybug, grape phylloxera and other gallforming insects, grape rootworm, red-banded

leaf roller, rose chafer, and pomace flies. Injury from one or more of these pests may occur throughout the growing season and reduce

the size and quality of the current crop and the

size of subsequent crops, and weaken the vines.

In the absence of control measures, losses are

high. Damage by a leafhopper in California

in 1960 was estimated at $4,840,000. General

use of recommended control measures in the

Great Lakes area has reduced damage by the

grape berry moth, and other insects are under

good control in that area.

Peaches and plums

Many kinds of insects and several species of

mites damage peaches throughout the United

States. Without the use of control measures

little or no marketable fruit could be produced.

In the area east of the Rocky Mountains losses

are due to leaf rollers, oriental fruit moth, plum

curculio, and sucking bugs, the more common

pests that attack the fruit.

Estimated annual losses caused to peaches by

specific insects for the period 1951-60 are as

follows :

Average

annual

loss

Insect (percent)

Peach tree borer 0.7

Other insects 3.3

Total 4.0

Pears

The major losses of pears are caused by the

codling moth, mites, and pear psylla. Other

insects may cause considerable damage at

times. Control of codling moth and mites is

much simpler on pears than on apples. Losses

because of failure to secure control are greatly

reduced in well-cared-for orchards.

The pear psylla, now occurring in all important commercial pear-producing areas, reduces the productivity of infested trees, causes

premature defoliation, and excretes honey dew

in which a sooty mold develops on leaves and

fruit. Control of the pear psylla has become

increasingly difficult in Oregon and Washington in recent years, because of the occurrence

of strains that are resistant to certain recommended insecticides.

Pecans

The size and quality of the pecan crop is

reduced annually by one or more of the insects

and mites that infest pecan orchards. The black

pecan aphid, the hickory shuckworm, mites,

the pecan nut and leaf casebearers, the pecan

phylloxera, and the pecan weevil are the

economically important pests that attack the

crop. They reduce—and sometimes destroy—

the crop and lower the quality of the nuts.

Although more and more growers are attempting to carry out an insect control program,

many growers accept losses due to insects and

mites and make no attempt to prevent them.

Many seedling trees are inaccessible to spray

equipment. Reduction in yield and quality due

to feeding of the hickory shuckworm occurs in

Alabama, Florida, and Georgia, and damage

to nuts by the pecan weevil and nut casebearer

is common in Georgia. Losses in yield and

quality by the more injurious species, including

the black pecan aphid, the hickory shuckworm,

the pecan nut casebearer, the pecan phylloxera,

the pecan weevil, and spider mites, occur in the

western portion of the Pecan Belt (Arkansas,

Louisiana, Mississippi, Oklahoma, and Texas).

These losses occur in native seedlings as well as

in cultivated varieties.

Estimated average annual losses caused to

pecans by specific insects for the period 1951-

60 are as follows :

Average

annual

loss

Insect (percent)

Hickory shuckworm 6.2

Pecan nut casebearer 2.0

Pecan weevil 1.0

Other insects 2.8

Total Î2F

Sfrawbernes

Many species of insects and related pests

attack strawberries and cause heavy losses to

growers. Mites and aphids suck the juices from

the plants and reduce yield and quality of the

fruit. Aphids also transmit plant virus

diseases. In southern California, commercial

strawberry fields are replanted each year as a

result of damage caused by the cyclamen mite.

This pest weakens the plants or kills them by

continuous feeding on the terminal leaves and

fruit buds. Several root weevils destroy strawberry plantings in the Northwest, and the

strawberry weevil damages the fruiting buds

in the Eastern States. Various caterpillars,

cutworms, flea beetles, and plant bugs also

cause losses.

Estimated average annual losses caused to

strawberries by specific insects for the period

1951-60 are as follows :
LOSSES IN AGRICULTURE

Average

annual

loss

Insect (percent)

Spider mites 10.0

Aphids and white flies 5.0

Soil insects 3.3

Cyclamen mite 2.7

Insects attacking buds and fruit 2.0

Foliage-feeding insects 2.0

Total 25.0

Japanese beetle

The Japanese beetle attacks about 270 kinds

of plants, including field and fruit crops, ornamentals, and shade trees, eating only the

foliage of some, and the foliage, flowers, and

fruit of others. When beetles are numerous, all

leaf tissue on favored hosts may be eaten and

the fruit destroyed completely, made unmarketable, or reduced in value. In addition, the grubs

feed on plant roots and may severely damage

lawns, golf courses, parks, pastures, and other

turfed areas.

The beetle is generally distributed over

about 100,000 square miles in the Eastern

States from southern New Hampshire and

Vermont into North Carolina and westward

into Ohio and West Virginia. Portions of

Indiana, Michigan, eastern Tennessee, and

49

northern South Carolina are also infested and

local colonies occur in several other States

Damage by the Japanese beetle has decreased

greatly m the older infested area where imported parasites and milky and other diseases

have become established, but overall losses are

maintained by spread to new areas where natural enemies are not yet well established

Losses in well-cared-for orchards are negligible

but may be high in the absence of treatment.

VEGETABLE CROPS

Table 14 shows that insects cause an estimated average annual loss of $185,892,000 in

vegetables.

Asparagus

The principal insects causing loss to asparagus are the asparagus beetle and cutworms.

They eat into the stalks, either destroying them

completely or causing deformed growths that

necessitate culling the plants. Asparagus beetle

larvae, the fern caterpillar, leaf miners, and

spider mites feed on the ferns and lower plant

vitality. Wireworms and millipedes eat the

roots, weakening the plants and reducing the

stand. The garden symphylan eats small pits

TABLE 14.—VEGETABLE CROPS : Estimated average annual losses due to insects, 1951-60

Commodity

Production

unit

Loss from potential production i

Reduction 2 Quantity- Value

Asparagus HundredweightBeans:

Green lima —do

Green snap —do

Broccoli —do

Brussels sprouts —do

Cabbage —do

Cantaloups do

Carrots —do

Cauliflower —do

Celery —do .

Cucumber, fresh market.- —do

Escarole —do

Kale —do

Lettuce —do

Melon, honeydew —do

Onions —do

Peas, green —do

Peppers, green sweet —do

Potatoes —do

Spinach —do

Sweet corn —do

Sweetpotatoes —do

Tomatoes :

Fresh market —do

Processing Ton

Total

Percent

15

13

12

17

17

17

8

2

17

14

21

7

17

7

8

18

4

7

14

4

19

8

7

7

IflOO units IftOO dollars

578 6,789

338 2,499

1,552 10,591

392 3,139

124 1,040

4,737 8,443

1,035 4,563

321 961

496 3,137

2,433 8,949

538 2,740

54 250

34 148

2,496 10,077

131 640

4,841 12,510

462 2,083

225 1,876

33,196 65,968

202 750

9,086 16,575

966 3,970

1,512 10,600

292 7,594

185,892

1 See table 2, footnote 1. 2 See table 2, footnote 2.
50 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

into the spears near the soil line during the

harvest season.

Beans

Bean crops of all kinds, whether for processing, fresh market, or seed, or for sale as dry

edible beans, are damaged by insects. Root

maggots and wireworms attack the sprouting

seeds and the young plants before they emerge.

Cutworms and the lesser cornstalk borer feed

on the stems of the young plants. Aphids, various caterpillars, cucumber beetles, leafhoppers, leaf miners, the Mexican bean beetle,

slugs, spider mites, and thrips attack the foliage. In some areas, the bean pods are damaged

by lygus bugs, the western bean cutworm, and

the corn earworm. In California, lima bean

pods are attacked by the lima bean pod borer.

In the South, the canning crop of cowpeas (or

blackeye beans) is damaged by the cowpea

curculio, which feeds within the immature seeds

causing them to be rejected for processing.

During the period 1951-60 the major losses to

beans were caused by aphids, leafhoppers, lygus

bugs, the Mexican bean beetle, root maggots,

spider mites, western bean cutworm, and wireworms.

With so many pests involved and so many

types of damage, it is difficult to estimate the

losses caused to beans by specific insects. One

loss not discernible to the grower is the dropping of pods due to insect feeding. The most

familiar loss to the grower of dry beans is the

cost of sorting out the partially damaged beans

at the warehouse. Another loss—the discarding

of the more severely damaged beans during the

threshing operation—is not often recognized.

Estimated average annual losses caused to

green lima and green snap beans by specific

insects during the period 1951-60 are as follows:

Average

annual

Crop and insect (percent)

Green lima beans:

Mexican bean beetle 8.0

Spider mites 3.0

Other insects _ 2.0

Total 13.0

Green snap beans :

Mexican bean beetle 7.0

Spider mites 3.0

Other insects 2.0

Total 12.0

Carrots

Carrots are injured by soil pests such as root

maggots, wireworm, and white grubs that burrow into the roots or leave feeding scars on

them. Aphids, caterpillars, and leafhoppers

feed on the leaves.

Celery

Aphids and leafhoppers suck the sap from

the celery plants and transmit virus diseases.

Spider mites also remove the sap from the

leaves and devitalize the plants, which reduces

yield. The celery leaf tier, celery looper, cutworms, and armyworms eat the foliage and detract from the appearance of the marketed

product.

Estimated average annual losses caused to

celery by specific insects for the period 1951-

60 are as follows :

Average

anyiual

loss

Insect (percent)

Aphids 5.0

Leaf tier 2.0

Looper 2.0

Cutworms 1-0

Spider mites 1.0

Other insects 3.0

Total 14.0

Coie crops

Cabbage, cauliflower, broccoli, brussels

sprouts, collards, kale, mustard, and turnip

suffer severe damage by a variety of similar insects. Losses are particularly heavy in the

South. Thirteen caterpillars are important

pests of cole crops. Development of resistance

to DDT by the cabbage looper and the imported

cabbageworm and lack of effective insecticides

that can be used safely on the plants have increased losses by these two insects in recent

years.

Other insects that damage cole crops in most

areas of the country are aphids, leaf-feeding

beetles, and root maggots. Harlequin bug, mole

crickets, stink bugs, vegetable weevil, and

several species of grubs also feed on these crops.

Corn, sweet

The corn earworm and the European corn

borer are the two most serious pests of sweet

corn. The corn earworm occurs over the entire

country. The European corn borer ranges from

the Atlantic Ocean west to eastern Colorado

and Montana, and south into Alabama, Arkansas, Georgia, Louisiana, northern Mississippi,

northeastern Oklahoma, and South Carolina.

Both insects damage the ears being grown for

market or processing. In addition, the European corn borer tunnels within the stalk,

weakening it and interfering with growth. In

certain areas in years of heavy infestation by

either insect, sweet corn cannot be grown

proñtably unless insecticides are applied. In

Florida and Texas, treatment with insecticides

to control the corn earworm has made possible

a valuable fresh market sweet corn industry
LOSSES IN AGRICULTURE 51

where previously the ears were so severely injured that they could not be marketed. Corn

sap beetles, cutworms, fall armyworm, Japanese beetle, rootworms, white grubs, and wireworms also infest sweet corn and, unless controlled with insecticides, they may cause serious

damage to the crop.

Estimated average annual losses caused to

sweet corn by specific insects during the period

1951-60 are as follows :

Average

annual

loss

Insect (percent)

Com earworm 13.8

European com borer 4.1

Soil insects 1.1

Total 19.0

Cucumbers, squashes, and pumpkins

Cucumbers and summer squashes are susceptible to severe damage by several insects, the

most injurious of which in the country as a

whole are aphids and cucumber beetles. The

pickleworm and the melonworm cause extensive

injury in the South and occasionally spread into

adjoining areas.

The squash vine borer and squash bug feed

on all squashes and on pumpkins. Cutworms,

leaf miners, and thrips are occasionally injurious to cucumbers, squashes, and pumpkins.

Yield has been reduced 50 percent or more in

many summer squash plantings in which the

pickleworm, the squash vine borer, or squash

bug was not adequately controlled.

Lettuce

In the Western States, young stands of fallplanted lettuce are attacked by various caterpillars. The beet armyworm, the yellovz-striped

armyworm, and various cutworms attack the

young plants soon after emergence. A little

later, the cabbage looper usually appears and

infests the fields from the time of thinning to

harvest. It often causes losses to mature heads

of lettuce, even when the best control measures

have been applied.

The corn earworm sometimes infests and

ruins entire lettuce fields after head formation

has started. The larvae work their way into the

center of the heads where they cannot be

reached by insecticides.

Aphids, chiefly the green peach aphid, are a

problem on lettuce grown for spring harvest in

the Western States. They sometimes become so

numerous near harvest that some heads must

be discarded. However, the greatest loss attributable to these insects is the transmission

from plant to plant of the virus that causes the

lettuce mosaic.

In Eastern United States heavy losses result

to lettuce from infestation by the aster yellows

disease transmitted solely by the six-spotted

leafhopper. Efforts to establish the growing of

head lettuce in the higher altitudes of western

Maryland and southwestern Pennsylvania were

terminated after several years of crop failure

caused by aster yellows transmitted by this

insect.

Estimated average annual losses caused to

lettuce by specific insects for the period 1951-60

are as follows :

Average

annual

loss

hisect (percent)

Cabbage looper 3.9

Corn earworm 2.3

Aphids .8

Total 7.0

Melons

Cantaloups in the Western States are attacked by leaf miners, southern garden and

western potato leafhoppers, and spider mites.

These pests cause a loss of foliage and subject

the melons to sunburn and a lowering of their

quality due to reduction of total soluble soHds.

Losses due to leaf miners are sometimes very

heavy. Losses caused by the southern garden

leafhopper and the western potato leafhopper

are sporadic.

In the West the beet leafhopper also infests

fields of cantaloups, especially in the early

stages of plant development. This insect transmits curly top disease, which frequently is responsible for heavy crop losses or even failure.

Aphids are a problem every year in all areas.

The principal damage by these insects in Arizona and California results from the transmission of mosaic viruses which in some years

cause severe losses and occasionally destroy

entire crops.

In the Southern and Gulf States, the pickleworm and melonworm cause severe damage to

cantaloups. The melon aphid and cucumber

beetles are also serious pests of cantaloups in

the South. Unless these several insects are controlled, profitable production of melons m this

area is not usually possible. The grubs of the

cucumber beetles attack the roots of the plants,

whereas the adults feed on the foliage and

transmit bacterial blight and squash mosaic.

Onions

The most destructive pests of onions are the

onion thrips, which draws the sap from the

leaves and damages the blossoms, and the onion

maggot, which feeds on the bulbs. The use oí

new insecticides has greatly reduced thrips

damage in recent years. The onion maggot,
52 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

however, began to increase over the Northern

otates in the early 1950's, when it developed

resistance to insecticides; in many areas, for

several years, damage reached 50 percent or

higher.

Estimated average annual losses caused to

onions by specific insects for the period 1951-

60 are as follows :

Average

annual

loss

Insect (percent)

Onion thrips 10.0

Onion and seed-corn maggots 8.0

Total 18.0

Peas

The pea aphid is the major widespread pest

of peas in the United States. It sucks the sap

from the leaves and transmits several mosaic

diseases. It reduces the yield of dry edible or

seed peas and lowers the quality of processing

green peas. Outbreaks of the insect in 1954 and

1958 resulted in direct damage of more than

25 percent to the pea crop of the Northwest.

Mosaic viruses carried by the insect caused

additional losses. The pea weevil grub feeds on

the immature seeds, making them unfit for

either food or seed.

Minor pests of peas are beet armyworm, cutworms, leaf miners, pea moth, seed-corn maggot, thrips, and wireworms. These insects are

mostly restricted to certain localities. In Oregon

and Washington the alfalfa looper has a high

nuisance value, as the larvae may find their way

into the processed peas.

Estimated average annual losses caused to

dry peas and green peas by specific insects for

the period 1951-60 are as follows :

Average

annual

loss

Crop and insect (percent)

Dry peas:

Pea aphid 4.0

Pea weevil 2.0

Total 6.0

Green peas :

Pea aphid 3.6

Alfalfa looper .4

Total 4.0

Peppers

Peppers are attacked by many of the insects

that feed on potatoes and tomatoes, the most

destructive and widespread of which is the

green peach aphid. Dipterous leaf miners are

destructive in California, Florida, and Texas.

The pepper weevil damages the crop in California, and the pepper maggot does in the

Northeast. Everywhere the young plants are

attacked by cutworms, which either chew or

cut off young plants. In California, it usually

is necessary to apply insecticides to control the

pepper weevil and green peach aphid.

Estimated average annual losses caused to

green sweet peppers by specific insects for the

period 1951-60 are as follows:

Average

annual

loss

Insect (percent)

Green peach aphid 4.1

Pepper weevil .8

Other insects 2.1

Total 7.0

Potatoes

The more economically important insect pests

of potatoes of widespread occurrence in the

United States are aphids, wireworms, Colorado

potato beetle, ñea beetles, and grasshojppers.

Blister beetles, cutworms, the seed-corn maggot, plant bugs, stalk borers, and white grubs

are also generally distributed but cause serious

losses only in limited areas in certain years.

Insects that cause severe damage to the crop in

limited areas only are the white-fringed beetles

in the South, and the potato psyllid in the high

plains area and intermountain region of the

West. Some of the aphids that damage potato

plants are also carriers of mosaic and leaf-roll

virus disease. It is still difficult, however, to

prevent the spread of virus diseases of potatoes

by controlling their insect vectors. Since 1953,

aphids, the Colorado potato beetle, and flea

beetles have become resistant to certain insecticides in some areas.

Except for the southern potato wireworm,

losses from wireworms and other soil insects

have decreased in recent years because of wider

use of the more effective insecticides. Nevertheless, such losses are still considerable. By

1956 the southern potato wireworm in the

Southwest had developed resistance to several

insecticides. New materials, however, have

given reasonably good control of this pest from

1958 to date.

The potato leafhopper, occurring generally

throughout the eastern part of the United

States, is the direct cause of hopperburn of

potato. Frequently, the presence of the small

inconspicuous leafhoppers is not recognized in

time to apply an insecticide to prevent hopperburn.

During outbreaks of the six-spotted leafhopper, the purple top virus disease transmitted by this insect becomes a serious problem,

particularly in the North Central States.

The potato crop in Colorado, Montana, western Nebraska, Utah, and Wyoming is subject

to outbreaks of the potato psyllid, which feeds

on the plants and causes the psyllid yellows
LOSSES IN AGRICULTURE

disease. Outbreaks can be predicted in time to

warn growers of the need to apply insecticides.

Estimated average annual losses caused to

potatoes by specific insects for the period 1951-

60 are as follows :

Average

annual

loss

Insect (percent)

Sucking insects 8.0

Foliage-feeding insects 3.0

Soil insects 3^0

Total 14.0

Spinach

In the Southern States spinach is chiefly attacked by the seed-corn maggot and the green

peach aphid. Damage by the seed-corn maggot

is sporadic, but at times entire fields need to be

replanted because of poor plant stands caused

by this insect. Aphids reduce the quality of the

leaves on which they feed. In the Northwest,

the alfalfa looper is a nuisance pest. Numbers

of the insect are never large but the pupae,

which are fastened on the underside of the

leaves, may go through processing of the crop

and show up in the finished product. For this

reason, infested fields frequently are not

harvested.

Sweetpotafoes

The foliage of sweetpotato is seldom damaged

appreciably by insects, but the larvae of several

cucumber beetles and flea beetles eat shallow

holes in the roots or make tiny tunnels underneath the skin. White-fringed beetle larvae and

wireworms also damage the roots. Recently,

cucumber beetles have become very diflScult to

control, especially in Louisiana, where the

banded cucumber beetle is abundant. During

1960, damage by this insect was so severe that

5 percent of the 65,000-acre Louisiana crop of

sweetpotatoes was abandoned before harvest.

In some areas the losses were as high as 50

percent.

The sw^eetpotato weevil usually is the most

destructive pest of sweetpotato in limited areas

of several Southern States where it occurs. It

attacks the crop in the field and in storage. The

grub burrows throughout the edible roots and

makes them bitter so that they are unfit for

food or feed.

Tomatoes

Tomatoes in seedbeds are attacked by cutworms, flea beetles, and other general feeders.

The transplants are injured by aphids, blister

beetles, various caterpillars, Colorado potato

beetle, leaf miners, potato psyllid, spider mites.

53

thrips, and tomato russet mite. The tomato

fruitworm and armyworms damage the fruit

and Drosophila flies contaminate it with their

eggs and larvae. The beet leafhopper transmits

to tomatoes the virus that causes curly top

aphids carry various virus diseases, and potato

psylhd nymphs are responsible for the nonpathogenic psyllid yellows on tomatoes. Damage by the beet leafhopper is confined principally to the west slopes of the Continental

Divide where, at times, abundance of the insect

results in almost complete crop failure. Leaf

miners have caused damage in California,

Florida, and Texas. Tomato russet mite is a

pest of tomatoes in Arizona, California, Colorado, Utah, and some Eastern States. The

cabbage looper and the Colorado potato beetle

have damaged tomatoes along the Atlantic

Coast.

LANDSCAPE FLOWERS AND ORNAMENTALS

Disfiguring of many outdoor ornamental

plants by aphids, borers, cutworms, mealybugs,

scales, and spider mites, and other pests reduces

the aesthetic value of such plants (not for sale)

in private, commercial, and public gardens.

Each year many shrubs and flowering trees are

replaced because of insect damage. A number

of ornamental plants such as boxwood and

gardenia have lost their popularity because the

homeowner has not been able to cope with the

insect damage. Annual losses by insects to these

plantings are estimated to be well above 16

percent, or a total of $768,000,000.

HORTICULTURAL SPECIALTIES

The term horticultural specialties is used by

the Bureau of the Census for a long list of

horticultural crops grown for sale (table 15).

None of these crops was included in the other

estimates given in this chapter. Losses to horticultural specialties caused by insects are estimated to be $79,062,000 annually (table 15).

This estimate does not include plants or other

items not grown for sale.

Aphids, mealybugs, scales, spider mites,

whiteflies, and other pests cause severe damage

to plants in commercial greenhouses and nurseries. Changes in horticultural practices and

the increase in resistance of spider mites to

acaricides have resulted in increased crop damage in greenhouses during the past decade.

Resistant strains of spider mites, recognized

first on roses in 1949, are now also widespread

on chrysanthemums and carnations.
54 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

TABLE 15.—HORTICULTURAL SPECIALTIES GROWN

FOR SALE : Estimated average annual losses

due to insects, 1951-60

Commodity

Losses from potential

production i

Reductions Value 3

Percent

Nursery products (trees, shrubs,

vines, ornamentals, etc.) 11

Cut flowers, potted plants, florist

greens, and bedding plants 13

Vegetables grown under glass,

flower seeds, vegetable plants,

bulbs, and mushrooms 6

Total

1,000

dollars

24,562

48,956

5,544

79,062

1 See table 2, footnote 1.

2 See table 2, footnote 2.

3 Based on wholesale value of sales

States, excluding Alaska and Hawaii;

Census of Agriculture.

in the United

from the 1959

Florists throughout the country depend more

and more on a few establishments for cuttings

of young plants of chrysanthemum, carnation,

geranium, and rose. As a result, new pests may

be inadvertently distributed to many areas and

cause serious losses before control measures

can be applied. Some of the pests that have

been spread in this way are the carnation shoot

mite on carnation, the Lewis mite on poinsettia,

Liriomyza leaf miner on chrysanthemum, and

strains of the melon aphid and the green peach

aphid that are particularly damaging to chrysanthemum.

LOSS TO HONEY BEE INDUSTRY

The greater wax moth destroys stored honey

combs and brood combs of weak or mediumstrength colonies, and causes damage to hives

and other apiary fixtures. The estimated average annual loss to beekeepers as a result of damage by this pest amounts to $500,000.
Chapter 5.-Weeds

Weeds are plants growing where they are not

wanted. They compete with desirable plants

for nutrients, water, light, space, and other

growth requirements. In addition, the cost of

controlling weeds is enormous. Thus, the losses

caused by weeds and the cost of their control

constitute one of the highest losses in the production of food, feed, and fiber. Weeds increase

the cost of labor and equipment; reduce the

quality and quantity of crop and livestock products; harbor insects, nematodes, and diseaseproducing organisms ; clog farm ponds, recreational lakes and streams, and irrigation and

drainage ditches ; and impair the health of livestock and humans. Weeds also cause losses and

heavy expenditures in nonagricultural areas

such as highway, utility, and railroad rights-ofway ; and parks, lawns, and forests.

Herbaceous weeds and many woody species

use tremendous quantities of water; certain

phreatophytes such as saltcedar use up to 7

acre-feet of water per year. Weeds thus reduce

the availability of water for agricultural, industrial, and potable uses in areas of critical

water shortage. The water requirement of

herbaceous weeds that infest crops is large as

compared to that of cultivated plants. For

example, the corn plant requires 368 pounds of

water to produce a pound of corn (dry-matter

basis), whereas lambsquarters and ragweed use

800 and 950 pounds, respectively, to produce a

pound of dry matter. The sunñower plant requires almost twice as much water as corn to

produce the same amount of dry matter, and

the water requirement of ragweed is three

times that of millet.

In this chapter, only estimated losses in production and quality of certain crop commodities

are included. Direct and indirect losses that are

attributable to weeds on farms but are not

included in these estimates are losses in efficiency of cropland use ; losses due to harboring

of insects, disease-producing organisms, and

rodents; losses in human efficiency due to

allergy-causing and poisonous weeds ; and other

similar losses. Estimates on costs of weed control are given in chapter 12.

Specific examples of weed problems that

cause serious losses in agriculture are presented. No estimates are given on weed losses

in some crops and situations, because of lack of

background data. Loss estimates are based on

the best data available, but in some crops extrapolations and comparative estimates were

necessary.

Estimated average annual losses by crop

groups due to weeds are presented in table 16.

TABLE 16.—Estimated average annual losses to

various crop groups caused bij weeds and

cost of controlling weeds, 1951-60

Crop group

Average

annual loss

lyOOO dollars

Field crops 1,543,415

Forage seed crops 29,609

Pastures and rangelands 632,325

Fruits and nuts 132,032

Vegetables 122,249

Total 2,459,630

Cost of controlling weeds 2,551,050

Grand total 5,010,680

FIELD CROPS

The estimated average annual reduction in

value of field crops due to weeds for the period

1951-60 is $1,543,415,000 (table 17). Losses

in crop value due to weeds ranged from 8 percent for cotton to 17 percent for oats, for rice,

and for soybeans. The estimated annual cost of

weed control in field and seed crops is about

$1,876,000,000 (chapter 12, table 54). Thus,

the estimated annual losses due to weeds and

the cost of their control in field crops total about

$3,419,415,000.

Coffon

A wide variety of annual and perennial

grasses, sedges, and broadleaf weeds constitute

major production problems in cotton. Annual

weeds such as barnyardgrass, crabgrass, morningglory, and pigweed also seriously damage

cotton quality and reduce cotton yield. Lateseason grass weeds in cotton, especially in the

irrigated regions of the Southwest, reduce cotton quality one or two grades.

In the Mississippi Delta, intensive use of preemergence herbicides, made necessary by the

lack of hoe-labor and satisfactory cultural practices, has excellently controlled annual broadleaf weeds and weed grasses. However, lack of

55
56 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

an adequate supply of herbicides specific for the

control of major problem weeds has resulted in

invasion of thousands of acres of Delta land by

johnsongrass, nutsedge, and redvine.

Grass v^eeds in cotton reduce fiber quality

and mechanical harvesting and ginning eflficiency. Losses in yield and quality due to weeds

are particularly high in the humid cotton-producing areas of the South and also in the irrigated cotton-producing areas of the Western

States. Average annual losses in the cotton

crop due to reduced yields and quality, caused

by weeds, amounted to about 8 percent of the

value of the crops, or $205,628,000 per year, for

the period 1951-60.

Corn

More than 30 species of annual and perennial

broadleaf weeds and grass weeds and sedges

reduce the yield and quality of corn each year.

In the North Central States and the Northeast,

barnyardgrass and foxtail have replaced crabgrass in importance, and lambsquarters has replaced pigweed as the major contributor to

weed losses. Johnsongrass and a wide variety

of perennial and annual broadleaf weeds cause

severe losses in corn production in the riverbottom soils of the North Central States. In the

southern humid regions, cocklebur, crabgrass,

johnsongrass, morningglory, nutsedge, and pigweed are major problems. Weed competition

for moisture, light, and mineral nutrients reduces both yield and quality ; and quality losses

also include dockage for weed contamination of

the harvested crop. Weeds delay maturity and

interfere with mechanized harvest of the crop ;

they result in a higher percentage of moisture

in the harvested grain and reduced harvesting

efficiency.

Rice

Barnyardgrass, other grass weeds, submerged and emerged aquatic weeds, and many

broadleaf weeds seriously reduce yield and

quality of rice. Weeds also greatly increase the

cost of seedbed preparation, levee construction

to maintain excessive water depth for weed

control, water management and utilization.

TABLE 17.—FIELD CROPS: Estimated average animal losses due to iveeds, 1951-60

Production

Loss from potential production i

Commodity unit

Reduction 2 Quantity Value

Barley

Beans, dry

Com

Cotton

Flax (seed)__.

Hops

Mints

Oats

Peanuts

Rice

Rye

Saiïïower

Sesame

Sorghum :

Grain

Forage

Sweet

Soybeans

Sugarbeets

Sugarcane

Wheat

Bushel

Hundredweight -

Bushel

Bale

Bushel

Pound

—do

Bushel

Pound

HundredweightBushel

Ton

Pound

BushelTon

GallonBushelTon

__do

BushelTotal

Cost of controlling weeds

Grand total

Percent

12

3 15

10

48

5 12

10

12

5 17

15

5 17

10

13

12

13

13

13

3 17

68

13

5 12

IfiOO units IftOO dollars

48,425 47,488

2,617 22,000

344,209 439,404

961 205,628

3,381 13,924

5,427 2,552

375 1,769

199,522 160,623

267,720 28,776

7,195 45,654

2,670 3,094

17,707 666

1,025 132

48,917 49,216

2,156 12,350

401 855

78,019 204,049

1,059 13,627

1,077 7,642

136,644 283,966

1,543,415

1,876,000

3,419,415

1 See table 2, footnote 1.

2 See table 2, footnote 2.

3 Includes losses of 2 percent in quality of dry beans

and 3 percent in soybeans due to weed seed dockage,

damage in cleaning to remove weed seed, split beans

due to presence of weeds, and off-flavors.

4 Includes losses of 2 percent in fiber quality due to

lowered grades caused by grass, weeds, and associated

trash.

5 Includes losses of 3 percent in quality of flax and

oats, 4 percent in rice, and 1 percent in wheat due to

weed seed dockage, delayed maturity, off-flavors, and

cleaning losses.

6 Includes losses of 2 percent in sugarbeet quality.
LOSSES IN AGRICULTURE 57

fertilizer practices, and planting and harvesting. Intensive use of 2,4-D and related herbicides to control broadleaf species has caused

an ecological shift in the weed population.

Barnyardgrass and other grass weeds, sedges,

and aquatics are now among the most serious

weed problems in rice production.

Estimated average annual losses in the potential value of rice due to reduced yield and

quality amounted to 17 percent, or more than

$45,654,000, for the period 1951-60. In addition to reducing yields, weeds were responsible

for reducing quality because the grain was

shriveled, immature, and contaminated.

Small grains (barley, oats, rye, and wheat)

Many annual and perennial broadleaf weeds

and grass weeds cause severe losses in small

grains. Canada thistle, field bindweed, milkweed, weed brome, wild buckwheat, wild garlic,

and wild oats infestations are increasing in

small grains. In addition, curled dock, quackgrass, weed brome, wild mustard species, and

other weeds continue to cause severe losses in

small grains. The herbicide 2,4-D and related

phenoxy compounds have been used extensively

to control weeds in small grains. The herbicide

2,4-D has been very effective in controlling

broadleaf annual weeds. However, losses have

increased from grass weeds such as weed brome

and wild oats and from perennial broadleaf

species such as milkweed, wild buckwheat, and

wild garlic. In addition, 2,4-D cannot be used on

about 35 million acres of small grains underseeded to legumes, because the legumes are

sensitive to the herbicide. Weed losses on this

acreage are heavy.

Postemergence herbicides are used to control

weeds on about 20 of 111 million acres of

barley, oats, rye, and wheat planted each year.

Quality losses in the small grain crops are due

to dockage for weed seed and fragments in the

harvested grain and to wild onion or garlic

bulblets, which cause off-flavor. Wild oats constitute one of the most serious problems in

small grain production.

Estimated average annual yield and quality

losses in barley, oats, rye, and v/heat due to

weeds were about $495,171,000 for the period

1951-60.

Sorghum, grain, forage, and sweet

Barnyardgrass, cocklebur, common morningglory, crabgrass, field bindweed, foxtail,

goosegrass, johnsongrass, kochia, lambsquarters, milkweed, nutsedge, pigweed, ragweed,

redvine, smartweed, sowthistle, sunflower,

trumpetvine, and other weed species severely

reduce yield and quality of sorghum. After intensive use of 2,4-D and related phenoxy herbicides to control broadleaf species in sorghum

an ecological shift in the weed population oc^

curred. Weeds tolerant to 2,4-D and difficult to

control increased. Among these weeds are field

bindweed, milkweed, nutsedge, and the grasses

such as barnyardgrass, foxtail, goosegrass, and

johnsongrass.

Thorough seedbed preparation, rotary hoeing, tillage with weed-control implements, and

from one to four sweep cultivations are used on

most of the sorghum crop to control weeds.

More than 21/^ million acres of sorghum are

treated each year with herbicides.

Estimated average annual losses in sorghum

due to reduction in yields and quality by weeds

amounted to 13 percent of the total value of the

crop, or about $62,421,000, for the period 1951-

60.

Oilseed crops

Flax (seed).—Weeds such as barnyardgrass,

cocklebur, crabgrass, foxtail, lambsquarters,

pigweed, ragweed, smartweed, sowthistle, wild

mustard, and wild oats are among the species

that most seriously limit flax production in the

North Central States. These same weeds plus

Canada thistle, curled dock, field bindweed, and

quackgrass cause serious problems in flax production in the West.

Recently, use of herbicides on flax has increased. For example, there was a threefold

increase in the acreage treated with herbicides

in Minnesota between 1951 and 1954. Increases

in other States where flax is grown were comparable.

Estimated average annual losses in the flax

crop due to reduced yield and quality caused by

weeds amounted to 12 percent of the potential

value, or about $13,924,000, for the period

1951-60 (table 17).

Peanuts.—Serious weeds in peanuts include

bermudagrass, cocklebur, crabgrass, Florida

parsley, goosegrass, morningglory, nutsedge,

pigweed, purslane, and sandbur. A gradual

shift from hand hoeing and mechanical weed

control to the use of herbicides has reduced

losses caused by weeds. In addition, southern

root rot, a disease of peanuts that is favored by

cultural practices needed to control weeds, has

been reduced.

Approximately 300,000 acres of peanuts are

being treated with herbicides each year. There

is considerable interest among farmers in increasing the use of herbicides in peanuts. Mixtures of herbicides have also shown promise for

controlling many broadleaf weeds, including

nutsedge and other weeds difficult to control m

this crop.

Estimated average annual losses in the peanut crop due to reduced yield and quality
58 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

amounted to 15 percent of the potential value,

or about $28,776,000, for the period 1951-60.

Soybeans.—Barnyardgrass, cocklebur, crabgrass, foxtail, jimsonweed, johnsongrass,

lambsquarters, morningglory, nutsedge, pigweed, quackgrass, ragweed, and smartweed are

serious weeds in most of the major soybeanproducing regions. Other species are serious in

certain regions. Weeds cause the greatest damage in the north-central and southern soybeanproducing regions. Extended periods of rainfall, which do not permit timely rotary hoeing

and cultivation, result in severe weed infestations and consequent severe yield and quality

losses in soybean production. In addition to the

area weeded by cultural v^eed control practices,

approximately 21/^ million acres of soybeans

are being treated with herbicides each year at

a cost of 11 million dollars. Cocklebur, pigweed,

and velvetleaf have become so serious in many

soybean-producing areas that more than

425,000 acres are being treated each year with

2,4-D and 4-(2,4-DB) to control these broadleaf species.

Weeds in soybeans in the Southeastern

United States are especially serious and cause

higher yield and quality losses than in the other

producing areas.

Estimated average annual losses in yield and

quality of soybeans due to weeds amounted to

17 percent of the potential value of the crop,

or about $204,049,000, for the period 1951-60

(table 17).

Sugar crops

Sugarbeets.—Barnyardgrass, cocklebur, crabgrass, foxtail, kochia, lambsquarters, pigweed,

sowthistle, sunflower, wild oats, and such

perennial weeds as Canada thistle, field bindweed, milkweed, and quackgrass continue to

spread and cause moderate to heavy reductions

in yield and quality of sugarbeets. Weed competition occurs primarily between the time the

crop is planted or emerges and the time the

weeds are removed by hand hoeing or cultivation.

Even with thorough seedbed preparation,

hand hoeing, and frequent cultivation to control

weeds in sugarbeets, it is estimated that average annual losses in the crop due to reduced

yield and quality caused by weeds were 8 percent of the potential value, or about $13,627,000,

for the period 1951-60.

Sugarcane.—Troublesome and damaging

weeds in sugarcane are bermudagrass, chickweed, cocklebur, curled dock, common morningglory, henbit, johnsongrass, nutsedge, pigweed,

purslane, smartweed, wild lettuce, and wild

mustard. These weeds are causing heavy reductions in yield and quality in U.S. mainland

sugarcane. Johnsongrass is a particularly

serious problem in mainland sugarcane, and on

many plantations in Louisiana it is the most

limiting factor in sugarcane production. There

has been an important ecological shift in the

seriousness of weed populations in sugarcane.

Before the extensive use of 2,4-D to control

weeds in this crop, broadleaf weed species were

more serious than grass weeds. In recent years,

the infestation trend of grass weeds has been

up, and yield reductions caused by these species

have been increasing.

There has been an increasing trend toward

the use of herbicides to control weeds in sugarcane. Herbicides are currently used extensively

to control some weeds in mainland sugarcane

and the sugarcane-producing areas in Hawaii,

Puerto Rico, and the Virgin Islands. All

Hawaiian sugarcane acreage is treated with

herbicides one or more times during the life

cycle of the crop.

Estimated annual average losses in yield and

quality of sugarcane due to weeds amounted

to about 13 percent of the potential value of the

crop, or about $7,642,000, for the period 1951-

60.

FORAGE-SEED AND GRAZING CROPS

Forage crops grown for seed

Bedstraw, bermudagrass, black medic, brome,

Canada thistle, chickweed, chicory, crabgrass,

curled dock, dodder, foxtail, henbit, johnsongrass, lambsquarters, pigweed, quackgrass, red

sorrel, smartweed, wild mustard, whitetop, and

other weeds cause severe losses in forage crops

grown for seed production. Dodder, a parasitic

weed that attacks alfalfa, red clover, and other

forage legumes, is a serious problem in the

Pacific Northwest and Middle Atlantic States.

Infestations of this weed are increasing in most

of the alfalfa seed-producing areas.

Use of herbicides to selectively control weeds

in forage crops grown for seed production has

increased rapidly. With the use of herbicides,

the weed population trends were toward grass

weeds and parasitic weeds such as dodder.

Forage and turf crop seeds grown for certification must be relatively free of weed seeds

before they can be sold. To prevent spread of

weed seeds through forage and turf crop seeds

grown for seed, very extensive seed-cleaning

equipment is installed in most seed company

establishments to remove contaminating weed

seeds. The cost of removing weed seeds from

forage and turf crop seeds constitutes a significant portion of the total weed losses in these

crops.

Estimated average annual losses in the value

of forage and turf crops grown for seed due to
LOSSES IN AGRICULTURE 59

TABLE 18.—FORAGE SEED CROPS: Estimated average annual losses due to weeds, 195i-eo

Loss from potential production i

Commodity

Production

unit

Yield

Reduction in— „

Total

^1 . reducCleanmg tion2

Quality loss

Quantity Value

Alfalfa Pound.

Bluegrass, Kentucky 3 do__

Brome, smooth do—

Clover :

Alsike do

Crimson do

Red „doWhite (including ladino)- do

Fescue, tall do

Grasses:

Miscellaneous

Turf 4

Legumes, miscellaneous ^

Lespedeza

Lupines

Orchardgrass

Ryegrass

Sweetclover

Timothy

__do

__do

__do

__do-_-

__do

_-do__-

_-do__-

__do___

__do___

Percent Percent

12 2

10 1

7 1

Trefoil, birdsfoot do_

13

14

15

12

9

11

12

12

14

10

10

8

12

Percent

4

5

4

5

5

5

4

5

4

4

4

4

3

5

4

4

5

4

Percent

18

16

12

19

20

22

17

15

16

17

17

19

14

14

13

15

14

17

lyOOO

units

23,897

2,186

922

1,554

2,906

15,515

659

3,071

9,230

1,979

12,032

19,174

3,040

1,056

10,302

4,057

3,241

178

1,000

dollars

9,502

1,050

189

513

852

6,218

457

886

1,995

859

1,319

2,897

149

296

1,094

540

599

194

Total 6 29,609

1 See table 2, footnote 1.

2 See table 2, footnote 2.

3 Includes Merion bluegrass.

4 Includes chewings fescue, red fescue, and bentgrass.

5 Includes common vetch, hairy vetch, purple vetch,

and Austrian winter peas.

6 Loss due to reduced yields and quality and to cleaning. Does not include costs of weed control; for these

costs, see table 55.

yield and quality reductions by weeds amounted

to approximately $29,609,000 for the period

1951-60 (table 18).

Pastures and rangelands

Estimated losses due to weeds, including

brush, in forage crops and on rangelands are

given in table 19 as losses in production of forage only. The estimated losses would have been

greater had information been available on weed

losses due to ineffective management of livestock, sublethal poisoning that is often undetected, mechanical injury to animals from

needles and thorns, and reduced quality of

animal products. In addition, because of lack

of adequate information, no estimates are included of losses from weeds in new seedings

of forage crops, from weeds in hay crops, or

from weeds in improved pastures. However,

losses in stand in new seedings of forage crops

and reductions in stand from weeds occur frequently. Also, losses in quality and quantity of

hay from meadows and of pasturage in improved pastures are significant.

These estimates do not include weeds that

reduce stands, make plants weak and spindling.

and even cause failures in establishing forage

crops, nor do they include poisoning of livestock grazed on weedy pastures and rangeTABLE 19.—PASTURES AND RANGELANDS : Estimated average annual losses due to weeds

and cost of controlling weeds, 1951-60

Loss from potential

production 2

Kind of land and location i

Reduction 3 Value 4

IfiOO

Percent dollars

Pastures and rangelands in 31 ^

Eastern States 20 o95,635

Rangelands in 17 Western States 13 236,b^ü

Total -- ^^2,325

Cost of controlling weeds 365,000

Grand total — 997,325

1 Includes grazing lands, cropland pasture, and forage

lands grazed.

2 See table 2, footnote 1.

3 See table 2, footnote 2. ^ ^ . . „i-,^^

4 Based on data from the 1959 Census of Agriculture

obtained from the Economic Research Service.
60 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

l^^^s. For instance, a bizarre abortion problem

in both beef and dairy cattle grazing unimproved, lowland pastures was unsolved for at

least 50 years in Wisconsin. Research showed

that abortions were caused by weeds that had

sublethal dosages of nitrate. Spraying these

weeds with 2, 4-D solved the abortion problem

in these pastures.

East.—Weed and brush species often attain

greater stature and density under the humid

conditions in the 31 Eastern States than they

do in the 17 Western States. Studies indicate

that controlling these weeds results in slightly

higher increases in forage in the West than in

the East. Control of hardwood brush species

typical of the Eastern States resulted in yields

at least four times those on untreated areas.

Oaks, gums, hickories, and other hardwood

brush species typical of the Eastern States

decreased yields of forage in experiments in

Louisiana, 69 percent; in Missouri, 77 and 88

percent; in Arkansas, 75 percent; and in

eastern Texas, 83 percent. Therefore, it is

estimated that brush reduced production in

these areas 75 percent. However, less dense

stands of brush occur in some areas, and some

sites are extremely low in fertility; therefore,

it was estimated that yields were decreased an

average of 64 percent on the 51 million acres

of grazing land infested with brush where control would improve grazing. The prorated loss

from brush on the entire 230 million acres of

land grazed in the 31 Eastern States equals 14

percent.

Estimated losses from herbaceous weeds

typical of the Eastern States, such as bitterweed, ironweed, ragweed, and undesirable

grasses, are based on available studies. In

Nebraska, losses in the amount of forage eaten

by cattle on continuously grazed pasture infested with ironweed, ragweed, and other

species ranged from 38 to 69 percent. In a

pasture study in eastern Oklahoma, ragweed

decreased yields 75 percent and there was a

50-percent reduction from ragweed on all pastures sampled in that State. In Mississippi,

weeds in a pasture reduced the forage eaten by

cattle by 22 percent. Because the pastures in

these experiments may have been more weedy

than the average, the average loss of 50 percent

from weeds was divided by two, giving an

estimated loss of 25 percent on the 55 million

acres of residual pasture. The prorated loss

from herbaceous weeds on the entire 230 million

acres of grazing land in the Eastern States

equals 6 percent.

Losses on grazing land from brush and from

herbaceous weeds for the 31 Eastern States

total 20 percent.

West.—Examples of weed and brush species

that cause losses on rangelands are blackjack

oak, cacti, chaparral, halogeton, juniper, larkspur, medusahead, mesquite, post oak, rabbitbrush, rubberweed, sagebrush, shinnery oak,

and weed brome. Many ranges have been overrun by brush and weeds that have encroached

after overgrazing or because of unfavorable

weather or other conditions. For instance, authorities in Oklahoma estimate that more acres

of land go back to brush each year than are controlled in the active brush-control program in

that State. Also, increase in mesquite, which is

accelerated by drought, amounted to 1 percent

a year during a 12-year period in southern New

Mexico. In addition, heavy losses are caused by

poisonous plants such as deathcamas, halogeton,

locoweed, and tall larkspur, which reduce vigor

and cause death of livestock.

Research on brush species in the 17 Western

States indicates that yield of forage where

brush is partially controlled is generally at least

three times that on untreated areas. In

Arizona, the occurrence of 250 velvet mesquite

trees per acre resulted in a 65-percent loss of

forage production. On Texas rangelands with a

ground cover of post blackjack oak, forage production was 83 percent less with a 65-percent

ground cover than with a 13-percent ground

cover. A similar type of brush infestation reduced production 78 percent in Oklahoma and

82 percent in Missouri. Other typical losses

are 76 percent from shinnery oak in Oklahoma ;

50 percent from sagebrush in Colorado; 60 to

72 percent from sagebrush in Oregon ; 75 percent from sagebrush in Wyoming; and 66 percent from juniper in Arizona. On the basis of

these data it was assumed conservatively that

brush reduced production 52 percent on the 169

million acres of the infested grazing lands

where brush removal could improve grazing.

Prorating this percentage over the entire 769

million acres in the 17 Western States gives an

estimated loss of 11.4 percent.

Data on losses from herbaceous and other

poisonous weeds are not readily available.

However, losses due to poisonous and herbaceous weeds were estimated at 5 percent on

264 million acres of rangelands infested with

such weeds. Prorating this percentage over the

entire acreage of grazing lands in the West

gives an estimated 1.7-percent loss. When the

prorated figures for losses from brush are

added to the losses from poisonous and herbaceous weeds, the total losses equal 13 percent.

FRUIT AND NUT CROPS

The average annual losses in potential value

caused by weeds in fruit and nut crops are

estimated at $132,032,000 (table 20).
LOSSES IN AGRICULTURE 61

TABLE 20. FRUITS AND NUTS : Estimated average annual losses due to weeds, 1951-60

Commodity

Production

unit

Loss from potential production i

Reduction 2 Quantity Value

Almonds Ton

Apples BushelAvocados Ton

Blueberries Quart-_

Cranberries Barrel-.

Grapes, fresh _ _ Ton

Grapefruit __do—

Lemons —do—

Olives - __do___

Oranges --do—

Peaches - BushelStrawberries ^- Pound

Tangerines - Ton

Walnuts __do„_

Total

1 See table 2, footnote 1.

2 See table 2, footnote 2.

Percent

7

3

6

20

10

15

5

5

4

5

6

25

5

5

1,000 iinits

3

3,604

o

7,885

119

533

87

33

2

286

4,239

147,612

10

4

1,000 dollars

1,961

6,672

590

3,290

6,493

44,828

2,549

2,227

350

16,066

8,488

36,170

523

1,825

3 132,032

3 Does not include costs of weed control; for these

costs, see table 56.

Small fruits

Blueberries.—^Weed losses in blueberries are

caused by broadleaf weeds and grass weeds, including bermudagrass, crabgrass, goosegrass,

lambsquarters, nutsedge, pigweed, ragweed,

and smartweed. These perennial and annual

weeds are a serious problem in new plantings

where they soon overgrow the young blueberry

plants unless intensive cultivation and costly

hand weeding are practiced. Older producing

plantings are also subject to the effects of weed

competition, which reduces yields and lowers

quality. Hand weeding, though effective, is

economically prohibitive. Close cultivation

usually causes severe mechanical damage to

branches and roots.

Cranberries,—Cranberries are grown commercially in five States on low-lying soils where

the topography is suitable for developing canals

for ñooding. Cranberries are broadcast planted

and cannot, therefore, be cultivated after they

are established. Plantings may be productive

for 10 to 20 years if weeds are controlled. Many

grasses, broadleaf weeds, ferns, and sedges, including bracken fern, nutsedge, redroot, and

witchgrass, are among the principal weeds that

cause economic losses. Annual ñooding as practiced in cranberry culture is effective in controlling some weed species, but it does not control

the weeds named above. Cranberries are low

growing and are, therefore, easily shaded by

weeds ; and diminished vigor and yield and associated reductions in such quality factors as

size, color, and flavor result.

Grapes.—Major areas of grape production

are in six States in the northeastern, northcentral and Pacific coast regions. The crop

had total annual value of approximately 160

million dollars in 1960. Losses in grapes are

caused by a number of weeds, including perennial grass weeds such as bermudagrass, johnsongrass, and nutgrass; and annual weeds, including barnyardgrass, crabgrass, fall panicum,

goosegrass, lambsquarters, pigweed, ragweed,

and smartweed. Weeds harbor insects and

disease-producing organisms and compete for

light and moisture and thereby reduce fruit

yield and quality factors such as size, color,

and flavor. Weeds also decrease harvesting

efficiency.

Strawberries.—The commercial acreage of

strawberries in some 30 States dropped from

approximately 140,000 acres in 1951 to approximately 95,000 acres in 1960. High production costs were the determining factor in acreage reductions. Control of weeds is one of the

major production costs.

The perennial nature of strawberries exposes

them to infestation by a succession of different

weed species, including summer and winter annual and perennial weeds. Principal weed

losses are caused by annual weeds, including

annual bluegrass, chickweed, crabgrass, henbit,

knotweed, lambsquarters, pigweed, ragweed,

and smartweed, all of which compete strongly

for light, nutrients, and water and reduce yield

and quality, including color, flavor, and size.

Because of their prostrate growth habit strawberries are easily overgrown by these successions of weeds and continuous weeding is, therefore, necessary. Hand labor is effective, but is

often unavailable or too costly.
62 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

Tree fruits

One or more fruits (apples, apricots,

avocados, cherries, citrus, dates, figs, olives,

peaches, pears, plums, and prunes) are produced commercially in most States. Weed losses

are caused by many annual and perennial

weeds. Bermudagrass, cheatgrass, johnsongrass, and quackgrass are among the principal

perennial grass weeds in many areas of production. Annual grass weeds of importance include barnyardgrass, crabgrass, fall panicum,

and goosegrass. Woody weed species, including

brambles, poison-ivy, and scrub brush of various species, are sources of economically direct

or indirect losses.

Weeds compete with the crops for moisture

and nutrients and reduce yields and quality of

fruits in dry seasons. They also add to the

burden of irrigation. Orchards infested with

poison-ivy are often difficult to harvest because

workers are unwilling to enter infested areas.

Intensive cultivation to control weeds causes

mechanical damage to trunks and roots, which

restricts uptake and translocation of nutrients

and water and provides loci for infection by

disease-producing agents. Weeds also harbor

nematodes, disease-producing organisms, insects, and rodents, and interfere with their

effective economical control.

Tree nuts

The principal areas of commercial production of tree nuts, including almonds, filberts,

hazelnuts, macadamia nuts, tung, and walnuts,

are in approximately 20 States (including

Hawaii) in the South and along the Pacific

Coast. Weed problems, therefore, relate to

many weed species of diverse character such

as bermudagrass, johnsongrass, nutsedge, annual broadleaf weeds, annual grasses, and

woody plants, including poison-ivy. Losses

due to weeds are caused by competition for

water nutrients and result in reduced yield and

grade of the product. Bark damage and injury

to the developing or mature nuts by cultivating

equipment cause additional losses. Ground

covers of weeds harbor rodents that feed on

roots and nuts and thus reduce both current

yield and longevity of the plantings.

VEGETABLE CROPS

Losses due to weed infestations in commercial fields were estimated for a number of

vegetable crops (table 21). Critical weed losses

occur in many minor vegetable crops not

mentioned here. Estimated average annual

losses to vegetable crops due to weeds for the

period 1951-60 are $122,249,000.

Beans, green lima

Weed losses in lima beans are caused by

many broadleaf weeds and grass weeds. Major

losses are due to crabgrass, goosegrass, and

pigweed. These weeds emerge with the crop

and after each cultivation. If rains prevent

early cultivation, the crop may be lost because

of weeds. Weeds that emerge after the last

cultivation compete for space, light, moisture,

and nutrients. Weed competition reduces yields

and lowers quality by reducing sieve sizes and

increasing the number of white, or overmature,

beans. Beans of low quality reduce efficiency

in the processing plant because expensive and

time-consuming quality separations are required and the percentage of high-quality pack

is reduced.

Commercial lima bean production is highly

mechanized. The efficiency of mechanical harvesting depends on effective weed-control practices. Weeds carried v^th the crop into the

bean viners cause losses due to carryover of

beans with the mass of weed and crop foliage.

Beans, green snap

Weed losses in snap beans are the result of

intense competition of a number of broadleaf

and grass weeds, including crabgrass, lambsquarters, and pigweed. Some varieties of snap

beans mature approximately 50 days after

planting. Large amounts of fertilizer and moisture are needed to maintain rapid growth.

Exposure to intense weed competition for even

a very short period can delay maturity, lower

yields, and reduce quality, including color and

uniformity of maturity of pods. Growing of

snap beans is being rapidly mechanized. Weeds

reduce the efficiency of mechanical bean pickers.

Yield losses due to weeds, therefore, occur during the harvesting.

Beefs, table

Annual broadleaf and grass weeds that

emerge with beets interfere with growth at a

critical stage and cause losses in yield and

quality factors such as color, size, and shape.

Beet plants are small at emergence and grow

slowly. During this initial period of slow

growth, weeds can quickly overgrow the beets,

especially in wet years. The small size of the

plants limits the effective use of mechanical

cultivating equipment. The eflftciency of mechanical and hand harvesting is impaired by

weeds.

Cantaloups, cucumbers, and watermelons

Major losses in cantaloups, cucumbers, and

watermelons are caused by weeds that emerge

after the lengthening vines prevent further

cultivation. Principal weeds include broadleaf
LOSSES IN AGRICULTURE

TABLE 21.—VEGETABLES : Estimated average annual losses due to weeds, 1951-^60

63

Commodity

Production

unit

Loss from potential production i

Reduction 2

Beans:

Green lima HundredweightGreen snap do

Beets, table do

Cantaloups do

Carrots do

Com, sweet do

Cucumbers :

Fresh market do

Pickling Bushel

Lettuce HundredweightOnions do

Peas, green do

Peppers, green sweet do

Potatoes do

Spinach do

Sweetpotatoes do

Tomatoes :

Fresh —do

Processing Ton

Watermelons —do

Total

Percent

38

39

36

6

39

10

6

6

7

37

4 13

47

43

5 13

64

47

47

6

Quantity- Value

1,000 units 1,000 dollars

157 1,538

905 7,943

153 289

776 3,422

1,123 4,326

4,782 8,724

269 1,370

897 1,233

2,496 10,077

1,345 4,865

1,501 8,331

225 2,680

7,113 28,272

656 6,567

482 3,970

1,512 15,143

292 10,849

1,875 2,650

7 122,249

1 See table 2, footnote 1.

2 See table 2, footnote 2.

3 Includes 2-percent loss due to reduction in quality.

4 Includes 3-percent loss due to reduction in quality.

5 Includes 22-percent loss due to reduction in quality.

6 Includes 4-percent loss due to reduction in quality.

7 Does not include the costs of controlling weeds; for

these costs, see table 56.

and grass weeds such as crabgrass, goosegrass,

lambsquarters, and pigweed. Weeds that

emerge with the crop are also critical in seasons

of initial high rainfall. Weeds quickly overgrow the foliage of vine crops. Yields are

lowered by reduced fruit set and size; and

fruit quality, including color, flavor, and texture, is lowered. Maturation of the crop is

irregular and marketing is difficult when weeds

are present.

Carrots

The control of weeds in carrots is a major

production problem because of the small size

and slow early grovrth of the plants, which

prevent effective cultivation. Weeds in carrots

include crabgrass, galensoga, goosegrass,

lambsquarters, pigweed, and ragweed and

others specific for each commercial production

area. A large part of the commercial acreage is

sprayed with Stoddard solvent or sulfuric acid

to control weeds. These herbicides are not fully

effective, and a number of weeds including

galensoga, ragweed, and others remain to

harbor insects and disease-producing agents

and compete for moisture, light, and nutrients.

Unless the weeds are removed by hand, they

reduce both yield and quality of the crop.

Corn, sweet

The principal weeds causing losses in sweet

corn are barnyardgrass, crabgrass, fall panicum, goosegrass, jimsonweed, nutsedge, pigweed, quackgrass, ragvj^eed, and smartweed.

Repeated thorough cultivation controls many

of these weeds between the corn rows. In years

of limited rainfall, weeds that remain in the

rows sometimes reduce yields as much as 50

percent. Sweet corn surviving on a limited

water supply because of weed competition produces low yields of poor-quality ears. Toughened seedcoats, low moisture content, and reduced soluble sugars are the result. Grades and

cash returns are lowered accordingly.

Lettuce

Lettuce is grown in areas with cool climates.

Irrigation is used in the absence of abundant

rainfall. Lettuce plants have small root systems and are, therefore, poor competitors for

nutrients and water. As a result, moderate

weed infestations can cause severe yield losses

when moisture is limited.

Onions

Onions are grown commercially in many

areas where there are wide ranges of weed
64 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

species and cultural practices. Major weed

losses occur during the early period of growth,

when the slow-growing, tender plants are becoming established. Grasses and broadleaf

weeds, unless effectively controlled, quickly

smother onion plants. Extensive cultivation

and hand weeding are required. Weather or

other conditions that interfere with control of

weeds can easily result in severe yield losses or

complete loss of the crop.

Principal weeds causing losses in onions vary

with the local climate; they include bermudagrass, crabgrass, goosegrass, lambsquarters,

nutsedge, pigweed, purslane, quackgrass, ragweed, and smartweed.

Peas, green

One of the principal causes of weed losses

in peas grown for canning and freezing

is Canada thistle. Peas are drilled in very narrow rows that do not permit cultivation in the

usual way. Thistle buds are the same size and

density as peas at harvest. They pass through

the viner with the peas and are carried to the

processing plant. Mechanical processing equipment will not effectively separate thistle buds

from the peas and, therefore, they must be removed by hand from the picking belt. Dockage

is determined by the number of thistle buds per

pound of peas, and cash returns to the grower

are reduced accordingly. Losses due to Canada

thistle have been lowered by use of herbicides.

Benefits from herbicides are reduced by lack of

general use, incorrect application, and the

effects of climate.

Yields and quality of peas are also reduced by

many annual and perennial grass and broadleaf weeds when moisture is limiting. Weed

competition under these conditions causes the

normally tender high-quality peas (small-sieve

size) to become hard. These small hard peas

are difficult to separate in specific-gravity and

mechanical-quality separators. They, therefore,

lower the grade of the processed product.

Grades of fresh peas are lowered, and the

grower receives less for this crop.

Peppers, green sweet

Weeds that emerge immediately after transplanting and after the final cultivation are the

major causes of weed losses in peppers. Wet

weather or other factors that interrupt weed

control measures during early growth can

severely reduce yield and quality or cause complete loss of the crop.

Setting of fruits on peppers is reduced under

low soil-moisture conditions. The strong competition of weeds for moisture during the blossoming and fruit-setting period can, therefore,

cause severe yield losses. Competition for

moisture during fruit enlargement often causes

severe quality losses due to blossom-end rot.

Perhaps the most troublesome weeds in

peppers are the annual grasses (barnyardgrass,

crabgrass, and goosegrass). Many broadleaf

weeds such as lambsquarters, pigweed, and ragweed contribute to the general weed complex.

Potatoes

Potatoes are grown commercially in many

geographical areas representing a wide range

of climates, soils, and cultural practices. Principal weeds contributing to losses in potatoes

vary accordingly; among others they include

barnyardgrass, bermudagrass, crabgrass, fall

panicum, goosegrass, lambsquarters, nutsedge,

pigweed, quackgrass, ragweed, and smartweed.

Perennial grasses, including bermudagrass,

nutsedge, and quackgrass, reduce yields and

cause potato tuber damage by penetrating roots

and stolons. Grade losses up to 25 percent,

caused by tuber damage, have been observed.

Late-season broadleaf and grass weeds that

emerge, in some instances, after the last cultivation interfere with mechanical digging and

may reduce the efficiency as much as 50 percent.

Large clumps of weeds and associated soil

passing over the digger belt carry potatoes

with them that are covered and lost. Losses

of more than 20 percent have been observed.

Spinach

Spinach is grovm in many geographical

areas during fall, winter, and spring. Weed

losses during the early stages of growth in fall

plantings are caused by a number of warmweather weeds, including crabgrass, goosegrass, lambsquarters, and pigweed ; the kind of

weed depends on location. Cool-weather weeds,

including annual bluegrass, chickweed, henbit,

knotweed, and peppergrass, are also a major

cause of economic loss.

Competition for moisture is critical during

the early stages of growth. Cultivation and

hand weeding can effectively control weeds.

Cost, however, prevents the unlimited and continuous use of labor in spinach and other pot

greens. As a result, the exposure of the crop to

short periods of weed competition between

weedings can be critical. Losses in yield and

such quality factors as color, texture, and

flavor are the result. Chlorotic leaves, tough

texture, and bitter flavor prevent marketing the

crop or greatly reduce its value. Hand weeding

also causes severe yield losses due to incidental

removal of crop plants with the weeds. Yield

losses of one-third have been observed.

Sweetpotatoes

Losses in sweetpotatoes occur as a result of

early-season infestations of annual broadleaf
LOSSES IN AGRICULTURE 65

and grass weeds, including barnyardgrass,

crabgrass, goosegrass, lambsquarters, and pigweed. Perennial grasses such as bermudagrass,

Johnsongrass, and nutsedge are also serious

weed problems. Annual weeds between the

rows can be controlled by cultivation until

runners become too long. Thereafter, weeds

must be removed by hand. Yields are reduced

by weed competition, and quality factors such

as size, shape, and color are lowered. Efficiency

of mechanical harvesting is radically lowered

by weeds.

Tomatoes

Major losses in tomatoes are caused by annual weeds that emerge with the direct-seeded

crop and those that emerge after the last cultivation of both direct-seeded and transplanted

tomatoes. Losses are caused by annual and

perennial grass weeds and annual broadleaf

weeds. Principal among them are barnyardgrass, crabgrass, goosegrass, lambsquarters,

nutsedge, and pigweed. Weed competition for

moisture during fruit enlargement reduces

yields. When weeds infest the crop, fruits are

small, full color does not develop, and blossomend rot often damages many fruits. In New

York and certain other Northeastern States,

early infestations of broadleaf weeds, including

pigweed and lambsquarters, are the major weed

problems. In the Middle Atlantic States,

grasses that emerge after the last cultivation

are of primary concern. These grasses often

overgrow tomato plants, interfere with harvesting, and produce humid conditions conducive to

fruit diseases, which cause additional losses.
Chapter 6.-lneff¡c¡ent Farm Operations and Fire

Crop production is subject to losses from inefficient farm operations. Mechanical damage

to crops is due, directly or indirectly, to unsuitable types and improper use of machines,

including excessive pesticide application and

improper fertilizer placement, planting, and

root pruning. All tend to reduce yields. Also,

some farm produce is subject to losses caused

by fire. Average annual losses from inefficient

farm operations and fire are estimated to be

about $510,887,000 for the period 1951-60

(table 22).

EXCESSIVE PESTICIDE APPLICATION

When pesticides are applied irregularly or

with too low concentration on the plant foliage,

larger amounts must be used than when they

are applied uniformly and efficiently. The average annual value of the material wasted for the

period 1951-60 is estimated at $64,847,000.

TABLE 22.—Estimated average annvxil losses of

agricultural crops caused by inefficient

farm operations and fire, 1951-60

Type of loss

Amount

of loss

1,000

dollars

Farm operation :

Excessive pesticide application i 64,847

Improper fertilizer placement 2 174,843

Improper planting 50,000

Eoot pruning 3 70,297

Fire 4 150,900

Total 510,887

1 Represents 10 percent of the cost of controlling insects, plant diseases, and weeds (includes cost of chemicals and application).

2 Represents 1 percent of total farm value of 59 crops.

3 Represents 0.5 percent of total farm value of all

cultivated crops.

4 From Agricultural Finance Review, Vol. 22, SuppL,

July 1961. Includes farm real estate, machinery, livestock, and stored products.

IMPROPER FERTILIZER PLACEMENT

Seeds and seedling roots are injured if the

soluble salts of fertilizer are placed too near

them or if too much is used. When the fertilizer

is too widely scattered or too far away, lack of

early plant stimulation, unavailability of part

of the plant food, or weed stimulation and competition result in decreased yields. Damage

varies widely, but average annual losses for the

period 1951-60 are estimated at $174,843,000.

IMPROPER PLANTING

Planting seed either too deep or too shallow,

insufficient compaction of the soil around the

seed, moist surface soil pressed into a firm layer

above the seed, improper elevation of the seed

row with respect to the general level of the land,

and other unfavorable planting conditions cause

either delayed or low germination and an inferior stand of plants. The adverse effects on

crop yields are manifest in many ways and are

frequently severe enough to require replanting.

Losses also result from faulty transplanting of

seedlings and the use of excessive amounts of

seed. Estimated average annual losses for the

period 1951-60 are $50,000,000.

IMPROPER ROOT PRUNING

A plant suffers from lack of water and nutrition when too much of its root system is severed

by tillage tools and furrow openers operated too

deeply in the soil or too close to the plant. The

location on the plant where the tools cause excessive pruning depends on the kind of crop or

nature of the root system, and the stage of plant

growth or extent of root development. Hot

weather and low soil moisture may aggravate

these effects, which are reflected in reduced

yield. Estimated average annual losses for the

period 1951-60 are $70,297,000.

66
Chapter /.-Harvesting and Storage Losses

HARVESTING LOSSES

Many losses in agricultural commodities can

be attributed to mechanical harvesting. When

crops were hand harvested, inferior or immature products were not gathered, and harvesting costs often amounted to one-half or

more of the total the producer received for

some crops. Mechanical harvesting is indiscriminate—inferior or immature products are

harvested along with good-quality mature products. But machinery has enabled the farmer

to tend more acres with fewer workers at less

cost and in better season than ever before.

Harvesting machines are designed for specific crops under specific conditions. When the

weather changes, methods and equipment must

be modified. Obviously, machines that work

well on level land when harvesting oats may encounter difficulty on hilly land when harvesting lespedeza or burclover.

A most important consideration is the moisture content of the crop at harvesttime. To

prevent shattering, to avoid harvesting during

inclement weather, and to make the most efficient use of harvesting machines, some crops

are harvested before the most desirable time.

As a result, crops often contain more moisture

than recommended for storage.

Average annual losses during harvesting of

crops for the period 1951-60 are estimated to

be $998,481,000 (table 23).

Cereals (wheat, oats, barley, rye, rke), safflower,

and sesame

Most harvesting losses of cereals are due to

(1) shattering of grain onto the ground and

breakage of straw when the crop is too dry, and

(2) improper adjustment and operation of the

harvesting machine. Timely harvest will help

to eliminate many of the losses due to shattering and breakage of straw, and some of those

caused by wind, hail, and insects. Cutterbar

losses can be minimized by proper reel adjustment, and other machine losses by correct cylinder speed, clearance between concaves, correct number of concaves, and proper airblast

adjustment. Grain is usually combined at moisture contents not best suited for storage.

TABLE 23.-—CROPS: Estimated average annual losses during harvest, 1951-60

Loss from potential production i

Production

ComiTiodity Reduction 2 Quantity Value

Barley Bushel

Castorbeans Pound

Corn Bushel

Cotton, lint and seed Bale

Flax (seed) Bushel

Oats do

Peanuts Pound

Potatoes HundredweightRice —do

Rye Bushel

Safflower Ton

Seed crops:

Grasses Pound

Legumes —do

Sesame —do

Sorghum, grain Bushel

Soybeans —do

Sugarcane Ton

Tung nuts do

Wheat Bushel

TotalPercent

5

7

8

5

5

5

15

7

5

5

5

17

30

10

10

8

5

10

5

1ft00 units 1ft00 dollars

20,177 19,787

2,144 117

275,368 351,523

775 125,383

1,878 5,802

71,258 47,242

267,720 28,776

54,536 108,375

2,767 13,428

1,335 1,547

6,810 256

66,344 8,573

231,692 46,216

854 110

37,628 37,858

36,715 81,620

414 2,939

9 610

62,111 118,319

998,481

1 See table 2, footnote 1. 2 See table 2, footnote 2.

67
68 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

Casforbeans

Harvesting losses of castorbeans are due to

(1) shattering of capsules, (2) improper adjustment and operation of the harvesting machme, and (3) cracking of seed during hulling

and handling. Timely harvest is often prevented because the field is too v^et to enter;

and v^hen the field has dried enough, the crop

has been damaged or depleted by adverse

weather. Improper adjustment and mismanagement of the machine during harvesting,

hulling, and handling fracture the seedcoats,

which causes the oily meats to deteriorate.

Corn

Losses during harvest of corn are due largely

to (1) ears dropping to the ground, (2) corn

shelled off ears, (3) stalks broken down, (4)

harvesting when corn is too dry, (5) crushing

of kernels harvested with too high moisture content, (6) improper adjustment and operation

of the machine, and (7) obsolete machinery.

Many of these losses can be greatly reduced by

earlier harvesting. This is practical if ventilation is used to dry the harvested corn or if

high-moisture corn is ensiled in airtight storage. Losses can be further reduced by proper

adjustment of snapping and husking rolls and

gathering points on the machine.

Cotton, lint and seed

Losses during harvest of cotton are due to

(1) plant population and irregular planting,

(2) cultural practices influencing ground contour, (3) time and method of harvesting (percentage of bolls open), (4) harvest delay caused

by weather, (5) bolls missed by harvester, (6)

improper adjustment and operation of the machine, and (7) improper defoliation.

Flax (seed)

Harvesting losses of flax (seed) are due to

(1) delayed harvest which results in dropped

bolls, (2) combining from the swath before the

crop is dry enough to thresh, (3) weather damage while the crop is in the swath, and (4) improper adjustment and operation of the combine. Flax is considered mature when 90 percent of the bolls have turned brown. Special

care must be given flax when it is to be used

as seed. The seedcoat is easily injured during

threshing if the seeds are dry.

Peanuts

Losses of peanuts during harvest include:

peanuts left in the ground because the digger

is improperly adjusted; peanuts separated from

the vine because of disease or during shaking

and windrowing operations; and losses that

occur in combine harvesting or manual handling

when the peanuts are stacked. Additional losses

in field-stacked peanuts are caused by weather

and birds. Improper equipment or methods for

artificially drying peanuts may cause loss in

quality.

Potatoes

Harvesting losses of potatoes include those

left in the field by the digger, some of them

because they were severely cut or otherwise

damaged. Harvesting losses can be reduced by

using large, improved diggers designed to avoid

damaging the potatoes and by setting the machines to dig deep enough to harvest the whole

hill and to gather suflficient dirt to protect the

potatoes as they go over the elevators and sorting belts.

Seed crops (grasses and legumes)

Losses of legume and grass seeds during

harvest include shattering of ripe seed before

it is fully mature and mechanical damage due

to rough handling by the combine cylinder, concaves, beaters, and fans. The result of mechanical damage to seed is low germination.

Much of the lighter seed is blown over if the

cleaner fan is not properly adjusted. Vacuum

machines are often used to pick up shattered

seed from the ground after combining. Such

machines are usually custom operated.

Sorghum, grain

Harvesting losses of sorghum are due chiefly

to (1) breaking off of heads, (2) breaking of

stalks, (3) shattering of grain, (4) incomplete

threshing, and (5) improper adjustment and

operation of harvesting equipment. Early harvest will prevent most losses due to breaking

of heads and stalks and shattering. Methods of

drying grain sorghum now being developed will

make early harvesting feasible.

Soybeans

Losses during harvest of soybeans are due to

(1) shattering of seeds, (2) breaking down of

plants, (3) improper adjustment and operation

of harvesting machines, and (4) breaking of

seed during threshing.

Sugarcane

Harvesting losses of sugarcane are due to

adverse weather, which prevents harvesting at

the proper stage of development. In some

years, freezes damage the crop before it can

be harvested. Field losses caused by improper

machine adjustment or operation are costly

because extra labor is required for gleaning;

however, the crop is usually saved. Loss of

sucrose is related to the time that elapses between harvesting and milling operations. Ex-
LOSSES IN AGRICULTURE 69

cessive field trash contributes to loss in sugar

production.

Tung nuts

A major portion of the tung crop is harvested by hand, and some losses are attributed

to lack of harvest labor. But the main cause

of loss is incomplete recovery of the fruit, which

is mixed with dead wood and leaves on the

ground. This accumulation of trash, together

with an uneven ground surface, also results in

inefficient mechanical harvesting.

STORAGE LOSSES

Sfored-procfucf insects

Estimates for the losses caused by storedproduct insects to agricultural products after

harvest are based on information from a number of sources. These sources include associaTABLE 24.—STORED PRODUCTS: Estimated average annvM losses caused by insects, 1951-60

Commodity

Production

unit Loss in quantity

Loss in

value

Almonds Ton

Apples, dried Bushel

Apricots, dried Ton

Barley Bushel

Beans, dry edible Bag

Cereal breakfast foods

Corn Bushel

Cowpeas, dry edible Bag

Crackers, biscuits, and pretzels

Dry corn milling products

Dry milk (nonfat)

Figs, dried Ton

Filberts —do

Macaroni and noodles

Oats Bushel

Peaches, dried

Pears, dried

Peanuts

Pecans Pound

Prepared flour and flour mixes

Prunes, dried Ton

Raisins

Rice HundredweightRye Bushel

Sorghum, grain —do

Tobacco :

Flue-cured leaf Pound

Other than flue-cured leaf —do

Manufactured products --do

Walnuts Ton

Wheat Bushel

Wheat flour

Wool:

Products

In pianos

Percent

4.0

2.0

1.8

2.5

.5

.4

5.5

.5

.4

.4

20.Ö~

2.0

.1

.01

1.5

2.5

7.0

2.0

.4

.75

2.3

1.5

1.2

3.4

.8

.12

.02

3.3

3.0

.4

Total1,000

units

11,804

2 74

Y2~723

4 84

2'34^343

44

1164

29

4 104,200

1 3,172

10 880

477

17,306

11 20,562

1 2,428

60,192

1,000

dollars

11,047

2 2,599

3 132

12,978

4 623

6 1,495

7 304,646

4 17

6 2,811

6 273

8 9 396

3 868

158

6 161

5 20

45

3 20

4 11,186

1790

6 1,651

3 227

3 9,803

10 4,311

5 1,016

7 19,383

1111,104

12 322

13 1,023

11,062

6 116,772

6 5,260

14 350,000

14 3,750

856,849

1 Production data and farm value, respectively.

2 Represents quantity sold and price received. SRS

Statistical Bui. 292 (1961) and 322 (1962).

3 Computed from data in SRS Statistical Bui. 322

(1962).

4 Quantity sold and amount of sales, respectively.

5 Value of total supply on hand (July 1) at average

prices received by farmers.

6 Value of shipments; taken from Annual Survey of

Manufacturers.

7 Value of total supply on hand (Oct. 1) at average

prices received by farmers.

8 Loss of 1.0 percent in quality only.

9 Computed on basis of announced ASCS purchase

price in most common container.

10 Value of total supply on hand (Aug. 1) at average

prices received by farmers. _ .

11 Data from USDA, Agr. Marketing Service Bui.

200 (1956) and 308 (1962). Represents stocks on hand

and average prices paid to growers, respectively.

12 Excludes foreign-grown and turkish types. Data

represent stocks on hand and average prices paid to

farmers.

13 Represents loss in retail sales adjusted downward

by an estimated markup of 20 percent. Basic data include value of Federal and State tobacco taxes.

14 Data furnished by the Market Quality Research

Division, ARS.
70 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

tions and individual members of industry; government agencies involved in the procurement,

storage, or distribution of commodities under

the government price support program; Food

and Drug Administration notices of judgments on foods seized because of insect infestation; and Federal, State, and industry

surveys. The information obtained ranged

from very precise to rather questionable data.

The reliability of the source and of the information obtained was considered in arriving at each

of the estimated losses. Whenever the information was questionable, a conservative approach

was used in estimating the loss.

The losses shown in table 24, unless specifically noted, reñect only the loss of value at the

time the insect damage occurred to the commodity. Furthermore, only the actual loss to

the commodity was considered. The cost of

handling and cost of insect control and sanitation, loss of prestige or business, and other

secondary costs resulting from damage or contamination by insects were not included in the

estimates.

Storage losses other than from insects

Losses in storage from causes other than insects occur in agricultural commodities in commercial or Government warehouses. These

losses are given in table 25.

Cereals (Wheat, Oats, Barley, Rye, Rice).—

Before the 1950's, most storage losses in cereal

grains, aside from insect damage, were caused

by mold and self-heating. The increased use of

driers before storage and improvements in

storage technology have reduced these losses a

great deal. It is diíRcult to accurately measure

losses from shrinkage or quality deterioration

and gains from quality improvement through

blending or for other reasons. For example,

as of January 1958, Commodity Credit Corporation had unloaded 15,917,765 bushels of wheat

that had been in storage for several years in

Government ships at Astoria, Oreg. The

quantity unloaded was 16,618 bushels less than

had been originally loaded and 1,487 bushels

had deteriorated in quality; 949,109 bushels

had improved in grade from No. 2 Soft White

to No. 1 Soft White because loss of moisture

during storage had improved the test weight.

The rest was equal in grade to that originally

loaded. Total loss from shrinkage and deterioration was only 0.1 percent.

A study of wheat stored in bins at 53 sites

in 29 counties in Kansas showed that average

losses in the net value of wheat due to shrinkage and deterioration were quite small. Some

21/2 million bushels of wheat from the 1952,

1953, and 1954 crops improved in grade while

stored for an average of 2 years; however,

weight losses resulting from removal of screenings resulted in a net decrease in value of 0.7

percent. Weight loss due to shrinkage was

0.55 percent.^

The Department of Agriculture's Farmer Cooperative Service concluded in 1955, after a

study of operating costs of new country elevators in the hard winter wheat area, that shrinkage of 0.25 percent appears reasonable in handling or merchandising grain under good management, with an additional shrinkage of 0.25

percent in storage.^

1 TAYLOR, J. W., and CLIFTON, R. E. SHRINKAGE LOSSES

AND GRADE CHANGES IN WHEAT STORED AT KANSAS BIN

SITES. U.S. Dept. Agr., Agr. Mktg. Serv. AMS-325.

1959.

2 FARMER COOPERATIVE SERVICE, U.S. DEPARTMENT OF

AGRICULTURE, NEW LOCAL ELEVATORS: COST-VOLUME RELATIONS IN THE HARD WINTER WHEAT BELT. Serv. Rpt.

12. 1955.

TABLE 25.—FIELD CROPS AND HAY: Estimated average annual losses during storage, 1951-60^

Commodity

Production

unit Loss in quantityLoss in

qualityLoss in

value

Crop:

Barley Bushel

Com —do

Flaxseed —do

Oats —do

Rice HundredweightRye Bushel

Sorghum, grain —do

Soybeans —do

Wheat --do

Hay, all Ton

Total

Percent lyOOO units Percent

i.a 2 2,317 0.1

2.0 3 47,953 .2

2.0 2 368 .2

1.0 2 10,294 .1

1.0 4 46 .1

1.0 2 144 .1

2.0 3 2,202 .2

.5 3731

1.0 2 4,886 .1

5.0 3 3,866 2.0

1 Does not include msect damage.

2 Average stocks, Oct. 1, 1951 to Oct. 1, 1960; first

estimate following harvest (crops of 1951-60).

3 Average stocks, Jan. 1, 1952 to Jan. 1, 1961; first

estimate following harvest (crops of 1951-60).

IflOO dollars

2,620

68,573

1,266

7,677

249

188

2,730

1,696

10,476

89,739

185,214

4 Average stocks, Jan. 1, 1952 to Jan. 1, 1961; first

estimate following harvest (crops of 1951-60). Sevenyear average stocks: 1952-53, 1957-61; 1954-56 not

estimated.
LOSSES IN AGRICULTURE 71

In another study, wheat from the 1952, 1953,

and 1954 crops stored in country elevators in

Kansas was examined for shrinkage and deterioration. Shrinkage losses totaled about 0.25

percent for a storage period averaging IOI/2

months. About half of the loss was attributed

to handling rather than to storage. The study

disclosed no change in grade of the wheat, and

the authors commented that, "Although loss

in grade is a risk in storing grains the results

of this study would seem to indicate that this

factor is not of any great significance in normal

operations of country elevators." ^ Most of the losses, other than insect damage,

in recent years have been due to handling, deterioration, shrinkage, and rodents.

Corn, Grain Sorghums, Soybeans, and Flaxseed.—Before the 1950's much of the loss in

stored corn, other than insect damage, was due

to mold and heating caused by high moisture

and inadequate ventilation. Since that time

the increased use of driers before storage has

decreased losses of corn in storage. A study of

some 18 million bushels of CCC-owned corn

from the 1948, 1949, and 1950 crops, stored in

bins in 10 Iowa counties for an average of about

3 years, showed an average annual loss of 0.85

percent from deterioration and 0.53 percent

from shrinkage. Deterioration occurred when

use of aeration was not widespread. The study

indicated that because of improvements in storage technology, **the costs of quality deterioration might be expected to be less for present

long-term corn storage than that incurred in

the 1948 and 1949 corn.''^

CGC records show that of 5,508,515 bushels

of wheat, corn, and other grains that had be-en

loaded in bins at 273 sites in Kansas from 1954

through 1958, 5,469,455 bushels were loaded

out—a difference of 39,060 bushels, or an average shrinkage of 0.7 percent for the entire

period of storage. At an additional 126 bin

sites, 1,607,596 hundredweight of grain

sorghums were loaded in and 1,597,750 hun9,846 hundredweight, or average shrinkage of

0.6 percent.

Most losses in storage, other than insect damage, are due to handling, deterioration, shrinkage, and rodents. Losses in farm-storage facilities are somewhat greater than losses in CGC

storage. Many farm-storage facilities are older

and are not as well protected against rodent

losses. Also, since driers are not used by all

farmers, the grain is sometimes stored with

the moisture content too high for safe storage.

Estimated storage losses of corn and grain

sorghums average about 2 percent of the production each year.

Estimated storage losses of soybeans average

about 0.5 percent each year. Storage losses

for soybeans are less than for corn and grain

sorghum for two reasons. First, during the

1950's there was very little carryover from one

year to the next since practically all of the soybeans were consumed. Second, most of the

soybeans are moved off the farms into commercial-type storage, and losses in commercialtype storage are less than in farm-storage facilities.

Estimated storage losses for flaxseed average about 2 percent of the production each

year.

A study was made of ñaxseed marketing

practices and costs at 265 country elevators

in North Dakota, Minnesota, and South

Dakota.^ These three States produce over 90

percent of the annual U.S. flaxseed crop.

Shrinkage from time of purchase to sale, including handling, averaged 1.53 percent at 175

elevators, or about 50 percent more than the

average of 1.01 percent in other grains. Shrinkage resulted from (1) elevating, conditioning,

and moving flaxseed within the elevators, (2)

removing small or broken flaxseed kernels along

with dockage in the cleaning process, (3) loss

of moisture between the time of purchase and

sale, (4) loading out flaxseed into boxcars or

trucks, and (5) leakage of seed en route to

dredweight were loaded out—a difference of terminals

:7t^I^j. w., and CMPTON, R. E. SHKXNKAOE AND ¿<.,Most 0^ the losses m A-s^f are due to

GRADE OF WHEAT STORED IN COUNTRY ELEVATORS IN

KANSAS U.S. Dept. Agr., Agr. Mktg. Serv. AMS-291.

. /4 MCDONALD, E. M. LOSSES FROM SHRINKAGE AND

L/QUALITY DETERIORATION OF CORN STORED IN COUNTRY

ELEVATORS AND AT BIN SITES IN IOWA. U.S. Dept. Agr.y

Agr. Mktg. Serv. AMS-173. 1957.

shrinkage. The small size and slippery nature

of flaxseed make it especially susceptible to

losses in handling and transportation.

5MANI0N, W. M., and ANDERSON, C. M. FLAXSEED

MARKETING PRACTICES AND COSTS AT COUNTRY ELEVATORS.

U.S. Dept. Agr. MRR-301. 1959.
Chapter 8.-L¡vestock and Poultry Losses

Losses are sustained by livestock and poultry

producers from infectious and noninfectious

diseases, parasitism, nutritional disorders, and

accidents (tables 26-30). With a rapidly expanding population, it is essential that these

losses be reduced or eliminated as soon as research discloses an economical means of so

doing. The United States is in a highly favorable position compared to the rest of the world

in having reduced or eliminated losses from

various causes. But in spite of the many advances that have been made, losses are still

substantial.

INFECTIOUS DISEASES

Infectious diseases are responsible for a large

part of the total losses in livestock and poultry

(tables 26-30). These losses, as great as they

are, represent only a fraction of those sustained

before some of the major infectious diseases

were brought under control or eradicated.

For example, in 1925 tuberculosis was estimated to be costing the livestock industry between 25 and 30 million dollars a year in direct

losses from condemned carcasses and parts of

slaughtered cattle and swine. At that time the

eradication program had been underway 8

years and the prevalence of the disease had

been reduced from 4.9 to 3.1 percent in cattle

and from 15.2 to 14.5 percent in swine.

Brucellosis was estimated to be responsible

for annual losses of $92 million before the accelerated eradication program was initiated in

1954. Elimination of most of these losses not

only has increased the income of livestock producers but, even more important, has increased

the supply of animal products and byproducts.

Some diseases are of special interest. Vesicular exanthema, a virus disease of swine, was

a relatively unimportant disease confined to

California until 1951, when it suddenly became

widely disseminated. Although an eradication

program was immediately organized and put

into effect, the disease cost the swine industry

an estimated $11 million before it was eradicated in 1956. 1 x^ XI

Anthrax does not cause a large loss to the

livestock industry as a whole. However, for

individual farmers, this disease can prove disastrous. Death losses are very high and so

rapid that usually the first sign noticed by the

farmer is the sudden death of several animals.

In endemic areas, there is little choice but to

vaccinate every year, and this adds to the cost

of raising livestock in those areas.

Rabies, a virus disease, does not cause large

losses either to the industry or to the individual

farmer. But it is 100-percent fatal once symptoms develop and is a public health menace.

Again, in endemic areas it is wiser to immunize

than to take chances with the disease, because

the cost of the disease far outweighs the cost

of immunization.

NONINFECTIOUS DISEASES AND

NUTRITIONAL DISORDERS

A large number of noninfectious diseases of

livestock, particularly of cattle, result in failure

to grow, reduced gains, the need for veterinary

services, and death losses (tables 26-30). The

origin of some of these diseases, but not all, is

nutritional. Reports from a representative

group of veterinarians in dairy sections showed

that 70 percent of their calls to treat and advise

on animal diseases were for those classified as

noninfectious. Since noninfectious diseases are

not the responsibility of State or Federal regulatory oflScials, except as they may affect the

meat when the animal is slaughtered, morbidity

and mortality reports are not made on them.

Therefore, almost no reliable information is

available on the number of animals that are

affected or die from these causes. About the

only useful information on these losses is in

meat inspection records that list tumors and

various other pathological alterations of the

organs and tissues not associated with infectious diseases at the time of slaughter.

The greatest losses from noninfectious diseases are due to faulty management and feeding. In cattle, bloat, milk fever, acetonemia,

calving troubles, sterility from endocrine disturbances, and chemical poisoning are common.

Sheep are also frequently lost from bloat, poisonous plants, chemical poisoning, ketosis or

lambing paralysis, and urinary calculi.

Pasture-improvement measures that result

in a lush growth of legumes have increased

losses from bloat; an effort has been made to

determine these losses and they are included

in the tables.

72
TABLE 26.—CATTLE :

Cause of loss

Total:

AnimalsMilk

Estimated average annual losses caused by infectioits and noninfectious diseases, 1951-60

Produc Loss due to mortality

tion

unit

Anaplasmosis 3

Anthrax: Beef

Bloat:

Beef

Dairy

Milk

Bovine hyperkeratosis

(X-disease) : Beef, dairy

and all calves 4

Brucellosis :

Beef

Dairy

Milk

Calf losses: Beef

Encephalitis (listeriosis) :

Beef

Foot rot: Beef

Grass tetany:

Beef

Dairy

Milk

Johne's disease:

Beef, dairy, and all calves

Milk

Ketosis :

Dairy

Milk

Leptospirosis :

Dairy

Milk

Mastitis :

Dairy _

Milk

Milk fever:

Dairy .

Milk

Poisoning, chemical: Beef_ _

Poisoning, plant: Beef _

Rabies: Beef

Tuberculosis: Beef _

Urinary calculi: Beef

Vibriosis Beef

Pound

- do

— do

-do

do

do.

-dodo

do.

do_

do_

do

do.

-do_

_do_

do_

_do_

_do_

_do.

.do_

-do.

do

do

_do^

do

_do_

-dodo

_ do

-do_

Loss duo to Diorl)idity

Reduction 1 Quantity 2 Value Reduction i Quantity" Value

Percent

'öröOÖT

.06

.4

.025

.4

.4

22.0"~

.002

.02

.001

.16

.02

.25

.15

.02

"T07~"

5.64

.001

.023

.6

1,000

units

83,941

37,220

6,728

55,961

37,220

5377526

280

2,798

93

43,057

1,861

op, 262

13,957

1,861

~977~93

89,537

140

.1,218

8,394

1,000

dollars

19

16,222

7,193

1,317

10,814

7,193

113,843

54

541

18

8,430

360

4,495

2,697

3G0

"L89>>

17,303

27

622

1,622

Percent

1.5

~ .~8

.009

.1

.5 "

.11

.002

.1

.1

.03

.15

2.0

7.26

.2

.07

.09

3.86

1,000

units

209,521

981~349

2,421

13,968

6137343

15,365

2,453

26,901

2,453

36,801

184,003

186,309

;.905,738

245,337

9,778

8,381

539,168

1,000

dollars

40,490

~4T,Ö35

474

2,699

2'5~,647

2,969

103

5,267

103

1,539

7,694

36,004

372,389

10,259

1,890

2,430

104,194

Total

Quantity

1,000

units

98

293,462

37,220

981,349

9,149

69,929

37,220

613,343

537,526

280

15,365

2,798

93

2,453

69,958

2,453

1,861

36,801

23,262

184,003

200,2(;(;

^,905,738

1,861

245,337

19,571

89,537

140

3,218

16,775

539,168

195,023

Grand total_

196,417

458,769

195,023

Value 2

1,000

dollars

19

56,712

7,193

41,035

4 1,791

13,513

7,193

25,647

113,843

54

2,969

541

18

103

13,697

103

360

1,539

4,495

7,694

38,701

372,38i)

360

10,259

3,783

17,303

27

6 622

4,052

104,194

391,440

458,769

^55,186 850,209

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1 See table 2, footnote 2.

2 See table 2, footnote 1.

3 See table 31.

4 3 years only? disease eradicated in 1954.

5 Based on data from 11 Western States.

6 Excludes loss of $117,240 in meat. 00
TABLE 27.—SWINE: Estimated average annual losses caused by infectious and noninfectious diseases, 1951-60 4^

Cause of loss

Production

unit

Loss due to mortality Loss due to morbidity Total

Reduction i Quantity 2 Value Reduction i Quantity 2 Value Quantity Value 2

Anthrax PoundAtrophie rhinitis

(sneezing sickness) __do __

Baby pig losses 3 HeadBrucellosis PoundCholeraErysipelas

Poisoning, chemical

Tuberculosis

Vesicular exanthema 8_

Total

_do_

__do

-do

-_do

-do

Percent

0.001

.0025

.07

.02

~M2

IfiOO

units

194

485

30,000

127^912

13,566

3,876

~~~388

1,000

dollars

34

85

240,000

"~~536

2,390

683

68

Percent

0.0005

.287

.07

~Ö2~'

~Ö28~

1,000

units

98

56,057

13,672

~3~,9Ö6

"M69

IfiOO

dollars

17

40,000

"9,~876

2,409

5 3,100

688

964

IfiOO

units

292

485

30,000

56,057

141,584

13,566

7,782

18,400

5,857

IfiOO

dollars

51

40,085

240,000

9,876

4 2,945

6 5,490

1,371

(^)

1,032

243,796 57,054 300,850

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1 See table 2, footnote 2.

2 See table 2, footnote 1.

3 Includes losses from all causes; data supplied by Animal Husbandry Research Division.

4 Excludes cost of biologies ($22,000,000).

5 Data from Animal Disease Eradication Division.

6 Excludes loss due to condemned parts ($416,000).

7 Losses in meat only ($3,250,000).

8 Disease eradicated in 1956; no loss thereafter.

TABLE 28.—SHEEP, LAMBS, AND WOOL: Estimated average annual losses caused by infectious and noninfectious diseases, 1951-60

Cause of loss

Production

unit

Loss due to mortality Loss due to morbidity Total

Reduction i Quantity 2 Value Reduction i Quantity 2 Value Quantity Value 2

Anthrax: Sheep Pound

Bluetongue: Sheep —do

Circling disease: Sheep -do

Death at birth and to v^eaning:

Lambs 4 Head

Enterotoxemia ; Lambs Pound

Foot rot: Sheep -do

Poisoning, chemical: Sheep -do

Poisoning, plant:5

Sheep

Wool

Rabies: Sheep

—do

-do

-do

Sore mouth:5

Sheep and lambs -do

Lambs, feeder -do

V iDriosis :

Sheep

Wool

—do

do

Total:

Animals _

Wool

Grand total

Percent

0.0003

.0001

.2

24.0

.5

.0001

IfiOO

units

1

(3)

647

7,000

6,261

~~324

(3)

4,161

IfiOO

dollarÍ:

(3)

(3)

50

67,953

1,278

25

4,430

""""(3)

848

Pereent

JMÎ9

~'22~"

IfiOO

units

707

IfiOO

dollars

55

T,378

4,560

IfiOO

units

1

6

647

7,000

6,261

707

324

4,161

IfiOO

dollars

(3)

(3)

50

67,953

1,278

55

25

4,430

1,378

(3)

4,560

848

.123 398 31 .3

.2

963

485

74

251

1,361

485

105

251

74,615 4,689

1,629

79,304

1,629

74,615 6,318 80,933

1 See table 2, footnote 2.

2 See table 2, footnote 1.

3 Less than $1,000.

4 Data supplied by Animal Husbandry Research Division.

5 Data supplied by Animal Disease and Parasite Research Division.
TABLE 29.—POULTRY AND POULTRY PRODUCTS: Estimated average annual losses caused by infectious and noninfectious

poultry diseases, 1951-60

Cause of loss

Production

unit

Loss due to mortality- Loss due to morbidity Total loss

Reduction i Quantity 2 Value Reduction i Value Value 2

POULTRY

Blue comb:

Chickens HeadTurkeys __do_.

Cholera :

Chickens

Turkeys

Enteritis: Turkeys

Erysipelas: Turkeys

Infectious bronchitis: Chickens

Infectious sinusitis (air sac infection) :

Chickens

Turkeys

Laryngotracheitis: Chickens

Lymphomatosis : Chickens and broilers

Mycotic disease: Turkeys

Newcastle disease: Chickens

Paratyphoid and paracolon infection :

Chickens

Turkeys

Pox:

Chickens

Turkeys do

Pullorum disease:

Chickens __do

Turkeys __do

Tuberculosis: Chickens do

Typhoid:

Chickens —do

Turkeys —do

_-do^.

__do_

_ do

__do__

-_do__

-do^

--do__

-_do__

__do__

__do__

_-do__

—do__

__do__

-_do_.

TotalPOULTRY PRODUCTS 4

Eggs, defects (chickens)

Eggs, low hatchability :

Chickens —do

Turkeys —do

Total:

Poultry

Poultry products

Grand total

Number--

Percent

IftOO

units

1,000

dollars

0.25

1.8

995

1,294

788

6,195

.38

.36

.83

.36

.85

1,513

259

579

259

3,360

1,197

1,239

2,856

1,239

2,659

3.0

.5

.2

(3)

.3

1.3

11,944

359

796

"~2Í6

5,176

9,451

1,721

630

58,960

1,032

4,095

.008

2.5

32

1,797

25

8,604

.047 187 148

.5

.4

.1

1,991

288

398

1,575

1,377

315

.35

.25

1,393

180

Percent

0.25

.9

.25

.25

.6

.54

4.0

.5

1.5

.09

~~r

.8

.03

.15

1,103

860

106,069

934,160

63,240

51,379

10,759

106,069

68,138

1,000

dollars

111

3,090

111

858

2,060

1,854

12,922

1,553

5,150

280

'~~343

2,485

2,060

93

515

34,817

79,200

34,817

79,200

174,207 114,017

1 See table 2, footnote 2.

2 See table 2, footnote 1.

3 Mortality: 1 percent in broilers; 10 percent in all other chickens.

4 Data supplied by Animal Husbandry Research Division.

IfiOO

dollars

1,565

9,285

1,974

2,097

4,916

3,093

15,581

11,004

6,871

910

58,960

1,375

6,580

25

10,664

241

515

1,575

1,377

315

1,103

860

140,886

79,200

51,379

16,759

140,886

147,338

288,224

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TABLE 30.—GOATS, HORSES AND MULES, MINKS, AND RABBITS: Estimated average annml losses caused by infectious and

noninfectious diseases, 1951-60

Cause of loss

Production

unit

Loss due to mortality Loss due to morbidity Total

Reduction i Quantity 2 Value Reduction 1 Quantity 2 Value

GOATS

Brucellosis Pound _

Poisoning, chemical - do__

Rabies _-doTotal

HORSES AND MULES

Anthrax

Equine encephalomyelitis

(sleeping sickness)4__

Equine rhinopneumonitis

(virus abortion)4

Infertility 4

Poisoning :

Chemical

Plant 5

Rabies

Respiratory disease (acute)4_

Strongyles ^

Head

-do

_ do

__do

__do

—do

—do

—do

—do

TotalMINKS

Bacterial diseases

Infant mortality

Mismanagement

Nursing sickness

Other nutritional diseases

Parasitic diseases

Urinary caculi

Virus diseases

Yellow fat

Total

RABBITS

Enteritis

Other disorders (including mismanagement)

Pneumonia

Total

Grand total -

1 See table 2, footnote 2.

2 See table 2, footnote 1.

Pelt

—do

__do

—do

__do

__do

__do

__do

__do _^

Pound

._do _

_ do .

Percent

0.1

.0001

.002

.01

.2

.0004

.48

18.0

.5

.1

.1

.12

.10

1.5

.02

12.0

6.0

6.0

1,000

units

38

(3)

1,000

dollars

4

(3)

38

(3)

(3)

(3)

(3)

(3)

450

4,750

2

36

(3)

25

100

5,363

20

735

20

4

4

5

4

61

1

396

14,848

412

82

82

99

82

1,237

17,254

10,557

5,278

5,278

3,174

1,587

1,587

6,348

Percent

0.63

.25

.1

.05

.12

.15

3.0

.01;^.

17.0

8.0

9.0

1,000

239

239

15,5.S6

7,311

8,225

1,000

(Ialtars

2(3

26

300

250

4,000

134

""475

1,900

7,059

776

202

81

40

97

121

2,419

10

3,746

4,(i71

2,198

2,473

9.342

1,000

/mits

239

277

26,093

12,589

13,503

Quantity 2 Value 2

1,000

elollars

26

4

(!)

30

(3)

750

5,000

4,000

2

170

(3)

500

2,000

12,422

1,172

14,848

614

163

122

196

203

3,656

26

21,000

7,845

3,785

4,060

15,690

49,142

3 Less than $1,000.

4 Data supplied by Animal Disease Eradication Division.

5 In 11 Western States only.

>

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LOSSES IN AGRICULTURE 77

The increased use of agricultural chemicals,

especially insecticides, herbicides, and fungicides, has directed attention to possible chemical poisoning as a cause of livestock losses. For

this reason, and because poisoning of livestock

by lead, arsenic, selenium, fluorine, and poisonous plants has been reported from time to time

by the Department of Agriculture and by some

of the veterinary college clinics, an effort has

been made to tabulate such losses.

Nutritional disorders of livestock and poultry

vary widely in nature, distribution, and intensity, and in the resulting economic loss. Obviously, they result from the feed that the

livestock and poultry consume. Nutritional disorders may result from either a deficiency or

an excess of a single nutrient or of several

nutrients. Sometimes nutritional disorders are

complicated with other classes of diseases.

Many nutrients are essential for animal life.

They include minerals, vitamins, proteins,

amino acids, fats, and carbohydrates. Various

metabolic and physiological factors, including

hormones, which regulate body functions, are

also involved. Accordingly, the number of possible nutritional disorders is extremely large.

Many are ill-defined or unrecognized. Only a

few are well described, and their regional or

nationwide importance is recognized.

The damage due to nutritional disorders may

result in death, reproductive failure, impairment of growth, or lowered productivity of

meat, milk, eggs, or wool. The quality of the

product may be decreased. No exact figures of

total losses are possible, because the diseases

cannot be segregated. Although feeding standards have been proposed or established for most

classes of livestock, actual requirements for

some of the essential nutrients are not yet

known. Therefore, ideal rationing of animals

is not yet possible, and there is no standard

by which to judge farm production.

The term **baby pig losses'' implies death.

Pigs may be dead at birth or, more likely, may

die within the first few weeks of life. Of all

pigs born, approximately 25 percent are not

raised to marketable weight. The losses given

in table 27 were determined from the per head

value of a pig at birth. The total dollar loss is

equivalent to about 6 percent of the total value

of production. These losses are traceable to

factors such as chilling, failure to nurse, injury, death directly traceable to the sow, and

various forms of enteritis due to infections or

nutritional factors.

Grass tetany, or wheat-pasture poisoning,

occurs chiefly among cattle and sheep grazing

on lush growths of green forages. During the

period 1951-60 there were severe losses in

cattle grazed on green-wheat pasturage in the

Texas Panhandle, and losses in both cattle and

sheep m Kansas, Oklahoma, and adjoining

areas. Losses occurred on other small-grain

pastures in Mississippi and on perennial grass

pastures in other parts of the country. The

exact cause of this disorder is unknown, but it

appears to be a physiological disturbance induced by the pasturage. In the wheat-growing

areas of the Southwest, the disease fluctuates

from year to year, depending on the weather

and the growth of wheat during the fall and

winter months.

Ketosis, or acetonemia, is one of the most

troublesome and widely distributed diseases of

milking cows. Animals are generally affected

early in lactation, with a resultant drop in

milk production. Death losses are low. About

4 percent of the milking cows are affected each

year.

Urinary calculi occur principally in cattle

and sheep, but losses are also serious in ranchraised mink. In cattle, the disorder is most

common in range areas and in the feed lots,

chiefly among steers. In sheep, the principal

losses are among wether lambs being fattened

in feed lots.

Each year low hatchability of poultry eggs

results in serious economic losses. Much of this

low hatchability is due to nutritional deficiencies or imbalances in the diets of the breeding

flocks, particularly vitamin and mineral deficiencies. Genetics, physiology, and management are also important factors.

The hatchability of chicken eggs is about

70 percent, which means that during the 1951-

60 period, an average of 934 million eggs that

were set each year did not hatch. The hatchability of turkey eggs is about 55 percent.

During 1951-60, about 63 million turkey eggs

that were set each year did not hatch.

Enteritis in rabbits has been tentatively

classed as nutritional in origin, or at least as

partly controllable by dietary means. Death

losses are high, and weight gains of young

rabbits are decreased.

Nursing sickness affects a significant number

of female minks each spring. They lose their

appetites and consequently their weight, and

milk flow decreases. Death losses are heavy

among the females as well as among their

young.

Yellow fat, or steatitis, in minks is now considered to be nutritional in origin. Affected

animals show brownish-yellow pigmentation

in the body fat. The death rate is high and

the pelts are poor quality. The disease occurs

in minks fed diets high in unsaturated fats and

low in vitamin E.
78 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

INTERNAL PARASITES OF LIVESTOCK AND

POULTRY

Internal parasites of livestock and poultry

cause losses in all parts of the country and in

all seasons. However, climate, especially the

weather from season to season, influences the

type, spread, and intensity of parasitism. In

general, warmth, moisture, and shade favor

parasites. Control measures, by and large,

are designed to take advantage of the destructive effects of unfavorable climatic factors on

the free-living stages of these organisms.^

About 300 kinds of internal parasites are of

economic importance in the United States. Some

are very common and abundant, others less so.^

Few animals are ever entirely free from them ;

and many harbor thousands of individual parasites, comprising a dozen or more injurious

species. Losses occur in animals and birds of

all ages, but are heaviest in the young.

The speciñc ways in which losses are sustained from parasites are legion, but a consideration of some of them will emphasize the

difficulty, if not impossibility, of arriving at

accurate estimates, as well as the reasons for

regarding all presently available information,

however carefully assembled, as fragmentary.

MorfaUfy losses

Mortality losses (table 31) include death

losses of breeder, or farm, stock and of stock

produced for market.

Morbidity losses

Morbidity losses (table 31) may be classiñed

as follows :

(1) Reduced yield and depreciation of animal products—milk, eggs, hides, wool,

mohair, casings, medicinal preparations.

(2) Condemnations of parts and carcasses

under Federal or other meat inspection

procedure.

(3) Waste of feed, labor, and space to bring

animals to productivity or useful maturity or to market.

(4) Interference with breeding and reproduction—sterility, diminished fertility

and vigor, delayed conception, abortion,

reduced litter size, lowered egg laying

of poultry.

(5) Reduced quality of animals—^lowered

, grades of market stock, reduced sale

^ value.

^ 1 LUCKER, J. T. CLIMATE IN RELATION TO WORM PARASITES OF LIVESTOCK. In Climate and Man, 1941 Yearbook

o'f Agriculture, pp. 517-527. 1941.

2 BECKLUND, W. W. REVISED CHECK LIST OF INTERNAL

AND EXTERNAL PARASITES OF DOMESTIC ANIMALS IN

THE UNITED STATES AND POSSESSIONS, AND IN CANADA.

Amer. Jour. Vet. Res. 25 (108): 1380-1416. 1964.

(6) Lowered efficiency of work animals

such as horses and mules.

(7) Depreciation of capital items—breeder

animals, farm properties, abandonment of production.

(8) Inefficient utilization of pastures,

barns, and pens by unproductive stock.

(9) Lowered resistance of infected stock to

other diseases and parasites.

(10) Deaths, sufferings, and anxieties imposed on man by parasites transmitted

from domestic animals, or by diseases

carried by parasites that are primarily

animal rather than human.

(11) Expenditures for worthless or inefficient drugs, treatments, and equipment.

Control costs

Control costs or charges ascribable to protection against parasites may be classified as

follows :

(1) Drugs for treatment, prevention, eradication, and control.

(2) Veterinary and other services, and

labor for administering drugs and

effecting control.

(3) Prevention of parasite introduction.

(4) Research—Federal, State, and private.

(5) Regulatory services (Federal, State,

and other), including inspection and

quarantine of animals, meat inspection,

and litigation.

Because internal parasites are ubiquitous, unseen, and of great variety and abundance, and

because their effects are generally inapparent,

they undermine the health of countless thousands of food animals and are a constant hazard

to efficient, profitable production. Vigilance

against parasites must be accepted as essential

for efficient management. There is no way to

estimate adequately or even to fully comprehend the hidden losses, and no attempt has

been made to include either the cost of measures directed toward the control of parasites

or the benefit accruing from these measures.

Among the principal objectives of the estimates in table 31 were conservatism and reliability, and an examination of the overall picture outlined above suggests that these estimates, for the most part, may be far too low.

The major items considered were (1) kinds

or categories of parasites affecting each class

of livestock; (2) their occurrence, distribution,

and relative capacities for causing economic

losses; (3) the nature of economic losses from

parasites; (4) the ways in which the individual

parasites injure their hosts; (5) official data

on populations and value of annual production

of the several classes of livestock and poultry

in the United States, and (6) individual judg-
TABLE 31.—LIVESTOCK AND POULTRY: Estimated average annual losses caused by internal parasites, 1951-60

Production

unit

Loss due to mortality Loss due to morbidity Total

Cause of loss

Reduction 1 Quantity 2 Value

Reduction 1 Quantity 2 Value Quantity Value

CATTLE

Anaplasmosis : Beef and dairy Pound

-do

__do

_-do

__do

__do

-do

-do

—do

-do

-do

—do

—do

—do

—do

—do

—do

-do

__do

-do

—do

__do

—do

Percent

0.2

.006

1,000

units

46,590

1,651

1,000

dollars

9,004

3,777

23,042

3,151

324

Percent

0.6

.05

IßOO

units

139,701

13,758

IfiOO

dollars

26,997

10,792

69,127

4,726

2,698

(5)

8,040

6 323

1,000

units

186,291

15,409

1,000

dollars

36,001

Coccidiosis : Beef, dairy, and

all calves 3

Gastroenteritis (worm parasites) : 3

Beef and dairy

14,569

92,169

All calves ' 7,877

Liver flukes : Beef, dairy, and

all calves 4 3,022

Tapeworms and bladderworms : Beef

Trichomoniasis, genital : Beef and

dairy 3

Other parasitic diseases: Beef and

dairy 3

(5)

8,040

6 323

Total 39,298

"~2~7'~

.032

.05

.55

.1

.02

"'6~,63Í

506

791

8,699

246

316

"''~6~877

6,877

122,703

848

10,967

3,427

7 90

141

1,550

127

56

(8)

13,652

3,554

17,206

""~6~631

553

949

8,857

246

711

'~~6~877

6,877

162,001

SHEEP

Coccidiosis: Lambs 3

Gastroenteritis (worm parasites) :3

Sheep and lambs

Wool

Liver flukes : Sheep and lambs "~~.OÔ3~

.01

.01

~'~Ô25~

47

158

158

395

150

7,315

8

28

28

70

998

18,282

3,427

7 98

Lungworms: Sheep and lambs

Nodular worms:

Sheep and lambs

169

1,578

Wool

Tapeworms: Sheep and lambs

Other parasites: Sheep and lambs 3

127

126

(8)

Total:

Sheep and lambs 7,599 21,251

Wool 3,554

Grand total 7,599 24,805

SWINE

Kidney worms 3 9

Lungworms 3

Nodular worms 3

Roundworm, large 3

Threadworm

Whipworms3

Total

"~.06~~ "Yl,628

512

171

683

2,048

34

~~"Ö2~ '"~3',876

16,547

3,413

6,836

34,129

683

683

"is'ööi

10 17,059

3,584

6,836

11 34,812

2,731

717

3,448 62,291 65,739

O

m

>

Ml

o

d

H

a

CD
TABLE 31.—LIVESTOCK AND POULTRY: Estimated average annual losses caitsed by internal parasites. 1951-60—Continued

Loss due to mortality Loss due to morbidity Total

X"1UUUCCause of lossProduction

unit Reduction 1 Quantity2 Value

Reduction 1 Quantity 2 Value Quantity Value

00

o

POULTRY 12

Blackhead: 3

Chicks and chickens HeadPoults and turkeys _do-_.

Coccidiosis:

Chicks and chickens do _.

Poults and turkeys do..

Eggs, chicken and turkey.

Percent

.5

.45

2.3

1.5

Hexamitiasis : Poults and turkeys 3_

Leucocytozoonosis: Turkeys

Trichomoniasis:

Chicks and chickens

Poults and turkeys

Capillarids : Chicks, chickens,

poults, and turkeys 3

Roundworms, except capillarids :

Chicks, chickens, poults, and

turkeys 3

Tapeworms: Chicks, chickens,

poults, and turkeys 3

Total:

Poultry

Eggs

Grand total

_do.

_do^

_do_

_do_

_do_

_do_

_do_

.012

.05

.12

.37

HORSES AND MULES

Piroplasmosis i^

Roundworm, large i^ _do_

Stomach bots 15 -do_

Strongyles (bloodworms) 3 15 _doTotal

Summary: Losses to livestock

and poultry:

Animals and birds

Wool and eggs

Meat condemnations 16

Grand total

.0005

.021

1,000

units

7,128

681

56,198

2,239

~~~3Í6

(13)

1,222

179

9,593

1,000

dollars

1,918

1,805

15,123

5,933

"~'~838

4

330

474

32

3,899

16

Percent

.45

.68

3.0

1.5

.018

.075

.018

IfiOO

units

1,000

dollars

2,877

2,708

19,731

5,933

317

1,057

62

493

712

1.23

30,372

30,372

100

(13)

4

54

.05

.05

.2

158

80,875

80,875

1,000

units

7,128

681

56,198

2,239

316

(13)

1,222

179

1,000

dollars

4,795

4,513

34,854

11,866

317

1,895

66

823

1,186

106 138

12,958 9,593 16,857

106 122_

46,743 77,115

317 317

47,000 77,432

400 500

9 9

36 40

490 544

935 1,093

246,324 327,199

3,871 3,871

9,136 9,136

259,331 340,206

>

O

a

Si

>

Ö

td

O

O

CD

H*

a

O

T)

O

>

O

W

O

1 See table 2, footnote 2.

2 See table 2, footnote 1.

3 Data supplied by Animal Disease and Parasite Research Division.

4 Includes weight loss and reduced milk production. Excludes loss of

$1,657,000 due to condemned livers.

ß Loss of $973,000 due to condemned livers and carcasses; excluded

from total.

6 Excludes loss of $472,000 due to condemned livers.

7 Excludes loss of $842,000 due to condemned livers and carcasses.

8 Loss of $37,000 in value of meat only; excluded from total.

9 Estimates limited to Southeastern States.

10 Excludes loss of $3,920,000 due to meat condemnations.

11 Excludes loss of $1,235,000 due to condemned parts.

12 Data based on both hatchery and farm production except leucocytozoonosis, which is based on farm production only.

13 Less than $1,000.

14 Data supplied by Animal Disease Eradication Division.

15 Based on data from Bluegrass region of Kentucky.

16 Includes losses itemized in footnotes 4, 5, 6, 7, 8,10, and 11.
LOSSES IN AGRICULTURE 81

merits of authorities on the comparative importance of diseases and parasites as causative

factors of economic loss among the several

classes of livestock.

Following are brief comments on certain

parasitic infections for which no loss estimates

were made.

Eperythrozoa are frequently seen in the red

blood cells of cattle in many areas of the country, often in conjunction with Anaplasma,

Certain difficulties have been encountered, however, in the correct identification of the organism. In this connection, there have been several

reports of a condition in pregnant cattle, diagnosed as eperythrozoonosis, in which some of

the cows and some calves died.

The Anaplasma organism has been reported

from sheep, but information is not available

on losses ascribable to the parasite.

Infection with Giardia, SL microscopic flagellated parasite of the intestine, was diagnosed

in a lot of feeder lambs in Utah. Because no

information is available on the effect of the

parasite on infected animals or on occurrences

elsewhere, estimates of losses were not attempted.

Eperythrozoa appear to have caused death

of some newly born pigs or very young swine.

However, data from which reliable loss estimates can be made are lacking. Infections with

this parasite have been found most frequently

in the Midwest, but they have occurred also

in Alabama, North Carolina, and Texas. In

some herds in Texas, about 50 percent of the

pigs were sick, and about 2 percent died. In

Missouri, 73 of 90 pigs farrowed by 17 sows

died during the first week after birth; death

was associated with Eperythrozoa infections.

In Iowa herds, mortality has been reported to

range from 10 to 40 percent. In a single herd

in Alabama, 21 of 70 pigs were affected and

9 died.

Infections of Trichomonas (trichomonads)

in the gastrointestinal tract and in the nasal

cavity are widespread among swine. It is not

known whether these parasites are associated

with gastrointestinal disorders; but flagellates

occur with some frequency in the nasal tract

of pigs affected with atrophie rhinitis.

The ciliated protozoan, Balantidium, occurs

in varying numbers in the large intestine and

blind gut of swine, particularly in hogs on

rations containing a high proportion of starch,

such as corn. This parasite, thought to be

transmissible to human beings, may not seriously inconvenience swine, however, unless

present in large numbers. Instances of severe

diarrhea associated with Balantidium have

been reported in swine fed a diet of corn.

Plasmodium, a malarialike parasite new to

the United States, was found in Wisconsin

chickens in 1961. Through 1962, it was found

in a total of 7 flocks in that State. The effect

of this parasite on the health of birds and on

egg production has not been determined, but

Plasmodium infections are reported highly

pathogenic to fowl in certain foreign countries.

There have been several studies of coccidiosis

in swine, but none relate to economic losses.

INSECT PESTS OF LIVESTOCK AND

POULTRY

All kinds of livestock and poultry are subject to year-round attack by a wide variety of

insects, ticks, and mites. Biting horn flies,

stable flies, horse flies, mosquitoes, black flies,

and certain ticks are serious pests during the

warm months. A new nonbiting fly, the face

fly, has become a major summertime livestock

problem in the Northeastern and North Central States. The cold winter months favor the

development of heavy infestations of lice, sheep

keds, cattle grubs, certain ticks, and mites on

animals. The screw-worm occurs throughout

the year in parts of the Southwestern States

and frequently spreads as far north as Kansas

and as far east as Mississippi during the

summer.

Losses to the livestock and poultry industries

directly attributable to insects, ticks, and mites

are difficult to measure. Damage from screwworms and fleece worms is readily apparent

to the grower, and he can assess losses on the

basis of the wounds ; destruction of tissue, wool,

and mohair; and death of animals. This is also

true with heavy infestations of lice, ticks, mites,

and sheep keds. Visible damage and measureable losses may also be determined from heavy

attacks of the face fly and biting flies and mosquitoes. Cattle grubs cause tangible losses in

damaged hides and carcass trim. Losses resulting from light or moderate infestations of

livestock and poultry pests, although they may

not be apparent to individual growers, constitute an important part of the overall loss m

the Nation.

Insect pests cause estimated average annual

losses in livestock and poultry of $877,850,000

(table 32).

Cattle

Face Fly.—The face fly, which was first

found in this country in New York m 1953,

now occurs in 32 States. It has become a serious pest of livestock in the Northeastern and

North Central States. The face fly does not

bite but its habit of clustering around the eyes,

mouth, and nostrils is extremely annoymg to
^2 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

TABLE 32.—LIVESTOCK AND POULTRY: Estimated average annual losses caused by insects, 1951-60

. Total

Cause of loss

All cattle and calves:

Face fly

Grubs

Homñy

Horse flies and deer flies

Lice

Mosquitoes

Scabies mites

Stable fly

Ticks

Total

Goats: Lice and mites

Sheep :

Bots

Keds

Lice

Scabies

Tick, including ear tickTotal

Swine: Lice and mites

Chickens and turkeys:

Fowl ticks

Lice and mites

Mosquitoes

Total

Grand total

Reduction in value i

Weight

IfiOO

dollars

42,000

115,000

115,000

30,000

41,000

15,000

3,000

74,000

60,000

495,000

8,000

9,400

4,700

2,000

4,700

616,050

Milk

1,000

dollars

26,000

55,000

64,000

10,000

6,000

10,000

'es'ööö

239,000

239,000

Production

1,000

dollars

2 22,000

22,000

3 800

22,800

IfiOO

dollars

68,000

192,000

179,000

40,000

47,000

25,000

3,000

142,000

60,000

756,000

800

8,000

9,400

4,700

2,000

4,700

28,800 28,800

3,000 3,000

4 750

75,000

13,500

750

75,000

13,500

89,250 89,250

877,850

1 Data furnished by Entomology Research Division.

2 Loss of hides.

3 Loss of mohair.

4 Losses limited to southern part of United States.

animals, interferes with their vision and

breathing, and prevents normal grazing. Large

populations force animals to leave pastures and

seek relief in v^ooded areas and shelters. The

face fly is such a new problem that its effect

on weight gains and milk production has not

been fully determined. This fly may be more

troublesome and cause greater losses than horn

flies.

Cattle Grubs,—Cattle grubs occur throughout the United States and cause serious losses

in the cattle industry, especially in the northern

half of the country where two species are present. Newly hatched grub larvae infest cattle

during the spring and summer, migrate through

tissues of the animal, and after 6 or 7 months

appear in the backs where they complete their

development over a period of 1 to 2 months.

Both the grubs and the adults developing from

them injure the animals and cause losses in

the following four ways :

(1) Reduced weight gains and milk flow.

Cattle infested with grubs do not gain as much

weight or produce as much milk as uninfested

animals.

(2) Damage to hides. Hides having five or

more grub holes are classed as No. 2 grade

and sell for $0.50 to $1 less than No. 1 hides.

Hides with large numbers of holes are fit only

for making glue and bring only 1 or 2 cents

per pound.

(3) Loss of meat in dressed carcasses. Grubinfested cattle are downgraded and sell for 1

or 2 cents per pound less than clean animals.

Loss from trimming away damaged meat, frequently from the best steak cuts, may average

$5 to $7 per animal slaughtered during the

grub season.

(4) Running from flies. Cattle tend to panic

when adult flies seek to oviposit on them. Animals frequently run to exhaustion trying to

escape, and many are injured or killed as a

result of colliding with each other or with obstacles. Running causes losses in weight and

milk production.

Horn Flies.—Horn flies are abundant in all

sections of the country during the warm

months. Many growers consider these insects

the most important of all pests of cattle. These

small, biting flies remain constantly on cattle
LOSSES IN AGRICULTURE 83

and feed on them several times a day. Their

biting irritates animals and prevents proper

feeding and resting; v^eight gains and milk

production are reduced. Studies by a number

of workers have shown that beef cattle treated

with insecticides to control horn flies gain

from 10 to 50 pounds per month more than

untreated cattle. Also, treated dairy herds

produce signiñcantly more milk than untreated

herds.

Horse Flies and deer Flies.—Horse flies and

deer flies are serious summertime pests in many

sections of the Southern, Midwestern, and

Western States. There is a succession of species

in most locations from late spring to early

fall, but, as a rule, three or four species compose the majority of the population and are

responsible for most of the loss. Most species

are somewhat larger than stable flies and their

bites are more severe and annoying. Small

populations can remove much blood from

animals and prevent them from grazing or

resting poperly. Losses from horse flies and

deer flies vary from year to year and from

location to location, in proportion to the population of the insects present. Some studies have

indicated that even small numbers of the flies

can reduce weight gains significantly and milk

flow by as much as 10 to 20 percent.

Lice.—Lice are very irritating to cattle and

cause reduced weight gains and milk production. Heavy infestations lower animal vitality

and can cause pronounced anemia. Cattle lice

are a year-round problem in most sections of

the country but the heaviest infestations and

damage occur during the winter months, especially in Northern States. In several of these

States lice are considered the most serious pest

of cattle.

Mosquitoes.—Mosquitoes are among the most

serious pests of cattle in western irrigated

areas, and in States that receive heavy rainfall.

The heaviest attacks frequently occur at night

so growers seldom observe or appreciate the

losses inflicted in reduced milk production and

weight gains.

Scabies.—Scabies mites produce skin lesions

and cause intense itching, which animals try to

alleviate by rubbing and scratching. Hides are

often severely damaged by the mites. Infested

animals do not feed properly and, as a result,

do not gain weight or produce milk at normal

rates. Cattle scabies mites of one or more kinds

are widespread but are most prevalent in the

North Central and Northeastern States.

Stahle Flies.—Stable flies are distributed

throughout the country, but are especially serious pests during the summer months in North

Central, East Coast, and Southeastern States.

These vicious biting flies are capable of reducing weight gains and milk production even

more than horn flies. Studies in lUinois have

shown that an average of 40 flies per animal

can reduce milk production by as much as 28

percent and reduce weight gains significantly.

Ticks.—Ticks are a spring-to-fall problem

for cattlemen in many sections of the country.

The spinose ear tick infests cattle the year

around and the winter tick is prevalent from

late fall to early spring in many areas. Ticks

are extremely irritating to animals and heavy

infestations cause unthriftiness, loss of weight,

and damage to hides. Lesions from tick bites

are a pathway for infections and, in the Southwest, they invite screw-worm infestation.

Gocr/s

Lice and mites are common pests wherever

goats are raised. They irritate the animals and

make them unthrifty. They reduce the production and quality of mohair. The action of goats

in biting and rubbing, to relieve irritation by

the pests, damages the hair and skin and may

render these products unmarketable.

Sheep

Ticks, mites, and insects such as lice, bots,

and keds attack sheep in all sections of the

country. Sheep infested with any of these pests

do not gain weight as rapidly as pest-free animals, nor do they produce as much or as highquality wool. Rubbing and biting by the sheep

to relieve irritation caused by the pests reduce

the amount and quality of wool and the value

of the skin.

Swine

Swine are subject to attack by one species

of lice and two species of mites. These pests

occur throughout the country and, if not controlled, cause important reductions in weight

gains and quality of the meat and skins.

Poüífry

Insects, mites, and ticks are common pests

of all classes of poultry throughout the country.

They cause birds to look unsightly, reduce

weight gains and egg production, and mar the

skin. The result is downgrading of quality and

lower market value. Heavy infestations cause

high mortality among young poultry. Workers

have shown that poultry lice and mites can

sometimes reduce weight gains and egg production from 2 to 25 percent or more.

Screw-worm (all Uvestock)

The screw-worm fly has been eradicated

from the Southeastern States, but it is still the

most serious pest of livestock in Texas ana

in parts of New Mexico, Arizona, and Oaii-
84 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

forma. In some years it spreads and causes

neavy losses as far north as Kansas and as far

east as Mississippi. This insect infests wounds

on animals, and the worms feed on the living

flesh. Infested animals become sick, do not

feed normally, and lose weight. In some years

m certain areas, the screw-worm infests every

newborn calf. If not controlled, the infestation

increases rapidly and results in the death of

animals within a few days. Constant vigil and

treatment are necessary from early spring to

late fall to prevent catastrophic losses from

this pest and require extra labor to locate

animals, chemicals for treatment, and feed for

hositalized stock. These extra, but necessary,

expenses increase production costs significantly.
Chapter 9.-Market¡ng and Processing Losses

Losses that occur during commercial marketing and processing of farm crops are considered

here. Losses that occur after the commodities

reach the kitchen are not included, nor are

marketing and processing losses of livestock

and poultry products.

Many tons of farm commodities are damaged or destroyed by diseases and other causes

between the time they are harvested and the

time they reach the dining table. The losses

are shared by growers, packer-shipper-storage

and transportation companies, processors,

wholesalers, retailers, and consumers. Losses

may be small, with only a trace of damage

throughout the load ; or they may be extensive,

with the entire carload or truckload spoiled.

Commodities that deteriorate after harvest

must be sold at a reduced price. Sometimes

additional costs are added in sorting out damaged produce and in repacking the sound product. Losses during marketing are more serious

than losses in the field or orchard, because the

cost of marketing services such as grading.

packaging, storage, and is transportation

added to the cost of the commodity.

MARKETING FRUITS AND VEGETABLES

There are a variety of causes of losses of

fresh fruits and vegetables after harvest. Most

obvious losses are caused by mechanical injury,

decay, and aging. Losses in moisture, vitamins,

sugars, and starches are less obvious, but they

adversely affect quality and nutrition. Rough

handling and holding at undesirably high or

low temperatures increase losses of all kinds.

Steps in marketing vary, but may include

storage, transportation, wholesale distribution,

and retailing. An overall estimate of losses

during the entire marketing period is, therefore, difficult to obtain.

The data in table 33 are, in part, from inspection certificates from the Pittsburg Produce Inspection Service for the period 1957-61.

The certificates are filed numerically, and the

tabulation was based on information from a

TABLE 33.—FRUITS : Estimated average annvM losses during transit and unloading

Commodity

Unit of

measure Loss in quantity i 2

Loss in

quality

Loss in

value 2

Apples

Apricots

Bushel

Ton

__do

-do

—do _ —do

-do

Box

Ton

Bushel

__do .

Ton

—do

-do

Pound

Ton

Percent

32

41

42

42

31

31

31

45

31

33

31

31

41

31

35

32

1,000

units

2,110

2

1

2

16

29

6

1

53

1,842

277

837

(5)

4

11,649

4

Percent

2.0

1,000

dollars

7,801

232

Avocados 181

Cherries 475

Grapefruit

Grapes

Lemons

Limes

.5

8.0

.1

722

13,626

436

64

Oranges

Peaches

Pears

Plums

Pomegranates _

Prunes

Strawberries

Tangerines

3.0

5.0

.4

1.0

11,841

9,768

707

285

2

2.0

5.0

3.0

1,328

5,017

468

Total 52,953

1 Percentage data include that part of the packaged

commodity which is inedible because of disease or destruction.

2 Basic data for quantity and value represent the

quantity marketed and value of the quantity marketed,

respectively.

3 Judgment estimates made by specialists.

4 Losses are based on information from inspection

certificates from Pittsburg Produce Inspection Service

from 1957 to 1961.

ß Less than 1,000 tons.

85
86 AGRICULTURE HANDBOOK 291, U.S. DEPT. OP AGRICULTURE

random sample representing about one-fifth of

the certificates. The PPIS contract covered

inspection for 16 firms. Before September

1961, when the Pennsylvania Railroad began

renting space on the railroad docks, contract

inspections primarily covered rail arrivals.

Since that time, many truck arrivals for the

contracting firms have been inspected. As indicated in the table, the data shown are not

strictly transportation losses. Storage losses

may be included for some commodities; also,

sometimes the inspections were continued during the period of unloading, and the losses include part of the losses during wholesale

marketing.

A statement is included on storage losses of

apples, grapes, and potatoes; an estimate of

losses during ripening and repacking is given

for tomatoes.

Information that may affect prices of vegetables as compiled from the Pittsburgh Inspection certificates is shown in table 34. These

include such factors as apple scab, tipburn of

lettuce, skin blemishes of citrus fruits, and

bruising injury.

Transit and unloading losses in fruits

Apples,—Losses of apples due to decay and

internal breakdown amount to about 2.2 percent during the transit and unloading period.

Internal breakdown causes more loss than decay. Partial loss such as scald, which would

affect the price, amounts to about 1.6 percent.

Decay during storage has declined in recent

years. Excepting apples stored for 7 months

or longer, the decay during storage probably

does not exceed 2 percent. Internal breakdown,

scald, bitter pit, and decay account for most

losses.

Apricots.—Brown rot, Rhizopus rot, and

gray mold cause about 0.8 percent of apricots

TABLE 34.-—VEGETABLES : Estimated average annual losses during transit and unloading

Loss in quantity

Commodity

Unit 0Î Loss m Loss m

measure Percentage i Amount 2 quality value 2

Artichokes

Asparagus

Beans :

Lima

Snap

Beets

Broccoli

Brussels sprouts

Cabbage

Carrots

Cantaloups

Cauliflower

Celery

Corn, sweet

Cucumbers

Eggplant

Escarole

Lettuce

Melons, honeydewOnions:

Dry

Green

Peas (in shell)

Peppers, sweet

Potatoes

Spinach

Sweetpotatoes

Tomatoes

Watermelons

Percent

Hundredweight- 31

Ton 43

Bushel 4 13

__do 48

__do 41

Himdredweight 3 0.5

Ton 42

Hundredweight- _ 31

__do 31

__do 31

—do 33

__do 32

—do

Bushel 42

—do 45

Hundredweight— 3 17

__do 33

—do 33

—do 34

—do 32

__do 31

—do 33

—do 31

—do 31

Bushel 4 19

Hundredweight— 34

—do 38

TotalIfiOO

units

3

35

54

385

6

10

12

195

151

118

76

294

79

23

122

976

44

916

3

4

87

2,010

18

2,055

767

2,299

Percent

0.4

3.0

.1

5.0

4.0

1.0

2.2

4.0

7.0

4.0

1.0

2.0

1.0

1.0

2.0

6.0

8.0

IflOO

dollars

31

472

445

3,328

16

149

102

1,622

503

3,115

1,127

1,620

89

400

120

701

13,139

497

3,060

37

31

987

8,160

318

8,591

13,681

6,499

68,840

1 Percentage data include that part of the packaged

commodity which is inedible because of disease or destruction.

2 Basic data for quantity and value represent the

quantity marketed and value of quantity marketed,

respectively.

3 Losses are based on information from inspection

certificates from Pittsburg Produce Inspection Service

from 1957 to 1961.

4 Judgment estimates made by specialists.
LOSSES IN AGRICULTURE

87

to decay during shipment. Decay per car

ranges from 0 to 19 percent.

Avocados.—Very little loss occurs in avocados during transit. Extensive losses may

occur during distribution and retailing if chilling temperatures go below 45° F., or if movement through retailing is slow enough to permit softening and breakdown.

Cherries.—Decay, due mostly to Rhizopus

rot, green mold, brown rot, and gray mold,

causes losses in cherries of about 2 percent

during shipment. Decay per car ranges from

0 to 49 percent.

Grapefruit.—Blue mold and stem-end rot

cause losses of about 1 percent in grapefruit

during transit. Decay ranges from 0 to 16

percent, and is lowest in December and highest

in July. Blue mold rot is the principal type

of loss in California and Texas fruit. The diseases are equally important in Florida.

Grapes.—Average losses during transit and

unloading of grapes is relatively small (1 percent). Losses are primarily due to gray mold

rot and Rhizopus rot. Grapes are usually sorted

following storage and storage losses average

about 4 percent.

Lemons.—Decay of lemons during transit

and unloading ranges from 0 to 8 percent with

an average of 1 percent. Blue mold rot, brown

rot, and alternarla rot are the main causes of

loss. The greatest losses in lemons occur following prolonged storage.

Limes.—Losses of about 5 percent caused by

blue mold rot and chilling injury occur during

marketing of limes.

Oranges.—Decay, caused mostly by blue

mold and stem-end rot, destroys about 1 percent

of oranges during transportation and unloading. Decay per car ranges from 0 to 25 percent. No stem-end rot occurs on California

oranges. Blue mold and stem-end rot are

equally important on Florida oranges.

Peaches.—Decay, mostly from brown rot and

Rhizopus rot, damages about 3 percent of

peaches during shipment. Decay per car ranges

from 0 to 35 percent. Serious losses also occur

if peaches are stored too long or at improper

temperatures.

Pears.—About 1 percent of pears decay during shipment. The decay is caused mostly by

blue mold and gray mold. Decay per car ranges

from 0 to 25 percent.

Plums and Prunes.—Decay, mostly from blue

mold and Rhizopus rot, causes losses of about 1

percent in plums and prunes during shipment.

Decay per car ranges from 0 to 11 percent.

Pomegranates.—Gray mold and blue mold

cause decay in pomegranates during shipment.

Decay per car ranges from 0 to 24 percent, and

averages about 1 percent.

Sirai(;&^rnes.—Decay, due mostly to ^rav

mold and Rhizopus rot, causes losses of about

5 percent in strawberries during transit and

unloading. Decay per car ranges from less than

1 to over 50 percent. Strawberries are highly

perishable and losses increase greatly with

each additional day on the market.

Tangerines.—Blue mold and stem-end rot

cause losses of about 2 percent in tangerines

during shipment and unloading. Decay per car

ranges from about 0 to 15 percent.

Transit and unloading losses in vegetables

Artichokes.—Most of the globe artichokes

are grown in California. Losses of about 1 percent occur during transit and unloading. Decay per car ranges from 0 to 8 percent. The

decay, which is mostly gray mold rot, is most

prevalent during the first 5 months of the year.

Asparagus.—About 3 percent of the asparagus decays during transit and unloading. Decay per car ranges from 0 to 44 percent and is

mostly bacterial soft rot, phytophthora rot, and

blue mold rot.

Beans, Lima.—Lima beans may be damaged

by gray mold, bacterial soft rot, watery soft

rot, bacterial blight, and other diseases during

transit and marketing. Some of these diseases

destroy the pods and beans. Others make them

so unattractive that their market value is

reduced.

Beans, Snap.—About 8 percent of the snap

beans shipped to market are lost during transit

and marketing because of watery soft rot, soil

rot, pythium rot, and gray mold rot. Salability

of the beans is reduced by pod spots caused by

bacterial blight or anthracnose. In some cars,

44 percent of the beans are affected.

Beets.—Most of the damage to beets during

transit and marketing is due to bacterial soft

rot and gray mold rot of the leaves of bunched

beets. This does not affect the edibility of the

root but does seriously detract from the market

value. About 91 percent of the shipments are

free of decay, but as much as 79 percent of the

beets in some cars may be affected.

Broccoli.—Decay of broccoli is not extensive

during transit and unloading. It ranges from

0 to 10 percent per car and averages about 0.5

percent. Most of the losses are due to bacterial

soft rot and gray mold rot and occur in shipments made from January through March.

Brussels Sprouts.—Bsicterml soft rot causes

losses of about 2 percent in brussels sprouts

during transit and probably additional losses

during marketing. It is found in about 40 percent of the cars shipped, and in some cars damage may be as high as 39 percent.

Cabbage.—Losses during transit and marketing of cabbage caused by bacterial soft rot.
88 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

watery soft rot, gray mold rot, and black rot

range from 0 to 26 percent and average about

1 percent during transit and unloading.

Carrote.—Bacterial soft rot, watery soft rot,

and occasionally certain other diseases cause an

average loss of about 1 percent in carrots during transit and marketing. Decay per car

ranges from 0 to 50 percent, and is worse where

carrots are shipped in polyethylene bags without adequate refrigeration. The average loss of

carrots for processing stored from 2 to 4

rnonths is about 10 to 12 percent and losses are

higher in some years.

Cauliflower,—Losses during transit and unloading of cauliflower average about 3 percent.

These losses are caused mostly by bacterial soft

rot, watery soft rot, and alternarla rot of the

curd. Bacterial soft rot may aiïect both the

leaves and the curd.

Celery.—An average of about 2 percent of

the celery is spoiled during transit and unloading. Most of the losses are caused by

watery soft rot, bacterial soft rot, and blackheart (physiological). These diseases rapidly

destroy the celery bunches and make them

unfit for food. About 56 percent of the shipments contain from a trace to over 50 percent

of decay.

Cucumbers.—An average of about 2 percent of the cucumbers are damaged during

transit. Losses are caused by bacterial soft rot,

cottony leak, watery soft rot, and chilling injury. The cucumbers in more than half of the

cars are affected, and decay per car ranges

from a trace to about 24 percent.

Eggplant.—Alternaria rot following chilling injury and phomopsis rot are the principal

causes of losses during transit and marketing

of eggplant.

Escarole.—Data on losses during transit and

marketing of escarole are too limited for making a satisfactory estimate. Tabulations from

29 carloads showed serious losses from bacterial

soft rot. The average loss from this decay was

17 percent. About 10 percent of the cars

showed no loss ; in the other 90 percent of the

cars, losses ranged from 1 to over 50 percent.

Lettuce.—Bacterial soft rot and watery rot

are the principal causes of losses in lettuce during transit and marketing. Losses from these

decays average about 3 percent, and decay per

car ranges from 0 to 50 percent. Much of the

bacterial soft rot follows tipburn, a physiological disease present at harvest. Diseases such

as tipburn, rib discoloration, russet spotting,

and pink rib cause losses either in reduced

prices or in excessive trimming. Of about

2,100 carloads tabulated, 12 percent had no

decay, 73 percent had up to 6 percent, 12 percent had from 6 to 15 percent, and 3 percent

had from 16 to over 50 percent.

Mu^kmelons (Cantaloup ).—Losses during

transit and unloading of muskmelons (cantaloup) average about 1 percent. About 51 percent of the cars are free of decay. In other

cars, superficial and penetrating decay ranges

from less than 1 percent to over 50 percent.

Most of the decay is caused by cladosporium

rot.

Melons (Honeydew and Honeyball).—Melon

losses during transit and unloading average

about 3 percent. Losses per car range from 0

to over 50 percent. Of the cars for which data

were tabulated, about 38 percent had over 5

percent decay. Cladosporium rot was most frequently reported.

Onions.—Bacterial soft rot, gray mold rot,

black mold rot, and smudge are the principal

causes of losses during storage, transit, and

marketing of onions. Losses from decay during

transit and unloading, which probably includes

some storage losses, average about 4 percent.

Decay per car ranges from 0 to 50 percent.

Freezing and sprouting cause additional losses

of about 1 percent.

Peppers.—Bacterial soft rot, Rhizopus rot,

gray mold rot, and alternarla rot following

chilling injury cause average losses of about 3

percent in peppers. Losses per car range from

0 to over 50 percent. Bacterial soft rot gains

entrance through stem ends torn during harvesting and during washing.

Potatoes.—^Losses caused primarily by bacterial soft rot and blackheart (a physiological

disease) average about 1 percent during transit

and unloading of potatoes. Losses per car

range from 0 to 50 percent, but the majority

of cars show less than 1 percent decay. Freezing injury during this period of marketing

takes its toll, but data on losses could not be

obtained.

Spinach.—The sample of data is too small

for making a satisfactory estimate on losses in

spinach. The cars for which data were tabulated had an average loss of 1 percent. Decay

caused by bacterial soft rot ranged from 0 to

8 percent per car, with the majority of cars

showing less than 1 percent.

Sweetpotatoes.—Losses in sweetpotatoes occur in storage, in transit, and on the market.

Data on losses, however, were not obtained.

Some losses occur because of chilling injury,

especially in the early marketing of uncured

roots. Most decay is caused by Rhizopus rot,

but other diseases such as fusarium rot, surface rot, and charcoal rot take a toll.

Tomatoes.—The principal causes of spoilage

of tomatoes during transit and unloading are

bacterial soft rot, watery rot, soil rot, Rhizopus
LOSSES IN AGRICULTURE 89

rot, gray mold rot, and alternaría rot if chilling injury occurs. Decay in the domestic crop

probably does not average more than 1.5 percent during transit. The data presented here

from the Pittsburgh market, however, involved

a number of shipments of Mexican-grown

tomatoes that developed extensive alternaría

rot during unloading. Transit losses, therefore,

were abnormally high. Decay averaged 4 percent and ranged from 0 to over 50 percent per

car. Additional losses during ripening and repacking of tomatoes shipped mature green are

estimated to average from 10 to 12 percent.

However, losses may be much higher in

tomatoes affected by such conditions as late

blight rot, chilling injury, or freezing injury,

or in tomatoes subjected to poor handling practices.

Watermelons.—Average losses of about 8

percent due to decay and breakage occur during

transit and unloading of watermelons. Losses

per car range from 0 to over 50 percent. The

decay is primarily black rot and stem-end rot.

However, watermelons from certain localities

show a very high incidence of anthracnose.

posed'' to the customer in order for it to sell

As a result, it is often roughly handled and

subjected to higher-than-desirable temperatures. When proper quantities are placed on

display, the product sells while its condition

IS still good. Overly large displays may result

in deterioration beyond limits acceptable to the

customer.

If the produce items remain in the display

after they have deteriorated, loss of sales for

the total display results.

One source of loss is the waste from trimming vegetables in order to present a salable

product to the consumer. Another source is the

discarded fruits and vegetables that are not

salable. However, a major loss in value occurs

from price markdowns or price discounting

because of deterioration in the product. This

constitutes almost two-thirds of the losses in

value to fruits and vegetables in retail stores.

Estimated average annual losses of fruits in

retail stores are $37,710,000 (table 35) and of

vegetables, $30,131,000 (table 36). The losses

shown in the tables are expressed in percentage

of full retail price.

FRUITS AND VEGETABLES IN RETAIL STORES

Most losses in retail stores depend more on

the ability of the produce manager to judge his

rate of sale than on any inherent differences

in the quality or condition of the product. In

self-service food stores, produce must be "exPROCESSING CROPS

In addition to the losses to crops and livestock at the farm level and those incurred in

transporting, handling, and marketing the unprocessed material, physical losses are incurred

during preprocessing and processing proceTABLE 35.—FRUITS: Estimated average annual losses during marketing in retail stores, 1951-60'^

Unit of Loss in

Commodity measure Loss in quantity 2 value 2

1,000 1,000

Percent units dollars

Apples Bushel 3 3,101 5,617

Cantaloups Hundredweight 4 471 2,077

Cherries Ton 2 4 877

Cranberries Barrel 1 11 115

Grapefruit Ton 1 15 474

Grapes —do 7 186 9,644

Lemons __do 7 40 2,719

Melons, honeydew Hundredweight 1 14 65

Oranges Ton .4 21 1,137

Peaches Bushel 6 3,573 6,740

Pears —do 2 548 960

Plums, fresh Ton 2 2 279

Prunes, fresh —do 2 9 859

Pomegranates —do .1 3 213

Strawberries Pound 10 21,900 4,465

Tangerines Ton 5 9

445

Watermelons Hundredweight _ 3 793 1,024

Total 37,710

1 Based on marketing studies in six retail stores

covering all four seasons.

2 Basic data for quantity and value represent the

quantity marketed and value of quantity marketed,

respectively, less the quantity and value of the losses

incurred during transit and unloading.
90 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

TABLE 36.—VEGETABLES: Estimated average annual losses during marketing in retail stores,

1951^60^

Commodity

Unit of

measure Loss in quantity 2

1,000

Percent units

Asparagus Hundredweight— 1 34

Beans:

Snap __do 2 96

Lima do 1 4

Beets __do 6 36

Broccoli __do 9 186

Brussels sprouts do 1 6

Cabbage __do 15 2,896

Carrots __do 2 299

Cauliflower __do 4 99

Celery __do 2 287

Cucumber do 5 197

Eggplant __do 21 88

Escarole do 11 55

Lettuce __do 7 2,279

Onions, dry __do 2 440

Peas (in shell) __do 10 38

Peppers do 13 363

Potatoes —do .2 398

Scallions —do 10 13

Spinach —do 3 55

Sweet potatoes —do 3 324

Tomatoes —do 6 1,105

Total

Loss in

value 2

1,000

dollars

398

832

34

97

1,480

51

365

905

599

1,037

1,001

404

190

8,277

1,163

311

3,048

799

88

308

1,356

7,388

30,131

1 Based on marketing studies in six retail stores

covering all four seasons.

2 Basic data for quantity and value represent the

quantity marketed and value of quantity marketed,

respectively, less the quantity and value of the losses

incurred during transit and unloading.

dures. Many of these losses could be avoided,

but some only at prohibitive cost. When products are improperly handled on the farm, preventive or corrective measures during processing are of little avail.

During the period 1951-60, improvements

in processing techniques have reduced physical

losses of many farm crops. For example, crude

cottonseed oil yield per ton of cottonseed

crushed has increased from a yearly average

of 316 pounds in 1942-51 to 334 pounds in

1951-60. For the 3-year period 1958-60,

average oil yield was 339 pounds per ton.

The distinction between avoidable and unavoidable losses is not always well defined.

The removal of fruit and vegetable peel or rind

before canning, freezing, or dehydration is an

example of the difficulty of making such a determination. Citrus rind is processed for

human consumption and as cattle feed; therefore, rind that is not recovered is a physical

loss of a byproduct but may not be an economic

loss because of the cost of recovery. Peels and

pits of some other fruits are not acceptable

for feed and when removed do not constitute a

loss in themselves. However, appreciable

amounts of the fruit or vegetable pulp may be

removed with the peel and would be considered

a loss. In the process of juice extraction there

are losses due to spillage and failure to recover the juice from the rag and peel. Economical recovery and use of these edible juices

has not always been possible, and frequently

where these juices are recovered it is done to

avoid stream contamination.

Another loss in processing crops is the reduction in nutritive value. Loss of carotene in the

harvesting, drying (in the field or in a rotary

drier), and storage of alfalfa is an example.

However, methods for reducing this loss are

available.

The discarding or unwise use of materials

known as agricultural residues has not been

included among the losses covered in this report. Among these materials are wheat and

other grain straws, corn stover and cobs, stems

and pods of soybeans, cotton stalks, and sugarcane bagasse. Uses for nutshells have been

suggested. One use is to return them to the soil ;

and they are frequently used as fuel. Cottonseed hulls and rice hulls are also frequently

used as fuel. Oat hulls are used in the production of chemicals. Possibly cottonseed and rice

hulls could also be used this way. If so, their
LOSSES IN AGRICULTURE

91

use as fuel might not be the best use for national welfare.

The percentage of loss on fruits and vegetables relates only to the loss of edible materials—materials that might have been used

as human food. Even though discarded edible

material is used for some other purpose such

as animal feeds, fertilizers, or industrial products, it is nevertheless considered a loss.

Field crops

Estimated average annual losses during

processing of field crops total $20,198,000

(tables?).

^ Rice.—In rice milling, bran layers adhere

tightly to the endosperm. Under present milling practices the bran layers can be removed

only by vigorous abrasion. Some broken grains

always occur from this step. The broken-grain

rice must be sold at lower prices than wholegrain rice.

Sugarbeets,—Beets grown for sugar are

subject to losses during storage and processing

in the mills through respiration of the living

beet tissue, destruction of the tissue by microorganisms, molasses formation, and inclusion

of sugars in wash waters. Unextracted sugar

in beet pulp is not considered a loss because of

the value of the sugar in the beet pulp when fed

to livestock.

Sugarcane.—About 7 million tons of cane

are processed annually in this country. Losses

arise from the presence of trash and dirt,

sugar inversion and loss of weight between

harvest and milling, and sugar left in the

bagasse during extraction. The sugar content

of blackstrap molasses is not considered an

economic loss because of the demand for

molasses in mixed livestock feeds.

Tung Oil—Tung fruit is hulled as a preliminary step to further processing in oil production. Tung hulls accumulate and present a

disposal problem Only limited use has been

estabhshed for these hulls. Their bulk is a

deterrent to shipping them to centers where

they might be used. Also, chemical constituents

such as potash or tannins can be obtained to

better advantage from other sources.

Oil is lost both in the hulling and in the expression of oil from the hulled fruit. Broken

kernels, which are the source of oil, and oil

released from the kernels on breaking are

carried along with the hulls as they are removed from the fruit. Improved methods of

separating the hulls from the fruit have reduced the loss of broken kernels in recent

years. In the milling operation, oil is either

polymerized or retained in the press cake and,

therefore, is considered lost.

Fruit crops

The estimated average annual losses in processing fruits total $45,493,000 (table 38).

Adequate and accurate data are not available

on losses occurring in the processing of fruits.

For example, companies can give figures on

yield of cases of canned fruit per ton of incoming fruit, but not on losses in preparation and

subsequent handling. The number of cases

per ton is not adequate for several reasons:

(1) The edible loss is not known and calculated

losses include inedible portions; (2) leaching

losses occur, replacing nutritive solids by

water, sirup, or brine; and (3) cans are filled

with both fruit and sirup, the fruit varying

by size and grade and the sirup varying in

density.

Only loss of edible material has been estimated. For example, in the production of

orange juice there is a loss of skin and seeds

and inedible and edible juice, which cannot be

or is not extracted by available methods. The

unextracted juice, later utilized in cattle feed,

is considered a food loss.

TABLE 37.—FIELD CROPS: Estimated average annuallosses in processing, 1951-60

Commodity

Unit

of

measure Loss in quantity i

Loss in

value 1 2

Maple sirup

Rice

Sugarbeets

Sugarcane

Tobacco-cigar binder

Gallon

Hundredweight

Ton

-_ —do

Pound

Percent

3 10.0

7.0

.4

1.4

5.0

1,000 units

147

3,588

50

96

1,896

1,000 dollars

678

17,534

578

684

724

Total 20,198

1 See table 2, footnote 1.

2 The average price of the crop produced was used to

determine the value of the processed product. The

average price may be a composite of the contract price

offered for the cream of the crop fresh, a lower price

offered for a fresh crop of lesser quality, and a still

lower price offered for the usable portion of the crop

remaining that can be used for processing.

3 Loss in value of production for sirup.
92 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

TABLE 38.—FRUIT CROPS: Estimated average annual losses in processing, 1951-60

Commodity

Unit

of

measure

Loss in quantity i

Loss in

value 1 2

Percent 1,000 units IjOOO dollars

Apples Bushel 12.0 4,124 7,695

Apricots Ton 8.0 14 1,653

Blackberries Pound- 5.0 1,608 156

Cherries Ton . _ 8.0 13 2,957

Cranberries Barrel 2.0 12 127

Figs, dried and canned Ton 1.0 (3) 56

Grapefruit __do 3.0 22 658

Grapes, dried 4 —do 7.0 60 3,077

Grapes, canned -do 7.0 2 118

Lemons -do . 3.0 7 475

Olives -do 7.0 3 615

Oranges -do 3.0 94 5,285

Peaches Bushel 20.0 6,202 12,416

Pears —do _ _ 12.0 1,921 3,510

Plums, fresh, canned

or frozen Ton 6.0 (5) 57

Prunes, dried —do 6.0 23 2,383

Raspberries Pound 5.0 2,188 350

Strawberries —do 10.0 23 3,356

Tung oil Ton 10.0 68 549

Total 45,493

1 See table 2, footnote 1.

2 The average price of the crop produced was used

to determine the value of the processed product. The

average price may be a composite of the contract price

offered for the cream of the crop fresh, a lower price

offered for a fresh crop of lesser quality, and a still

lower price offered for the usable portion of the crop

remaining that can be used for processing.

3 804 tons loss.

4 Dried for raisins, fresh basis.

5 333 tons loss.

6 Loss based on total production of tung nuts.

TABLE 39.—VEGETABLE CROPS: Estimated average annual losses in processing, 1951-60

Commodity

Unit

of

measure Loss in quantity i

Loss in

value 1 2

Asparagus Ton

Beans:

Green lima —do

Green snap —do

Beets —do

Broccoli HundredweightBrussels sprouts —do

Cabbage (kraut) Ton

Carrots HundredweightCauliflower --do

Corn, sweet Ton

Cucumber, pickling Bushel

Peas, green Ton

Potatoes HundredweightSpinach Ton

Sweet potatoes HundredweightTomatoes Ton

TotaL

Percent

3.2

6.0

5.0

7.0

20.0

10.0

5.0

18.0

8.0

20.0

5.0

6.0

5.0

10.0

15.0

5.0

IfiOO units lyOOO dollars

3 769

6 837

17 1,906

11 214

3 18 144

33 25

10 139

3 49 146

34 25

289 6,009

684 940

29 2,576

3 118 242

13 530

3 16 71

184 4,867

19,440

1 See table 2, footnote 1.

2 The average price of the crop produced was used to

determine the value of the processed product. The

average price may be a composite of the contract price

offered for the cream of the crop fresh, a lower price

offered for a fresh crop of lesser quality, and a still

lower price offered for the usable portion of the crop

remaining that can be used for processing.

3 1959-61 averages of quantities processed.
LOSSES IN AGRICULTURE 93

TABLE 40.— POULTRY AND POULTRY PRODUCTS : Estimated average annual marketing and processing losses, 1951-60

Cause of loss

Marketing

unit Quality

Loss in—

Quantity Value

Chickens and turkeys: i

Grade reductions for

bruises, cuts, etc

Eggs and chickens : 2

Broken (cracked)

Defects

Grade reductions

Total

Number-

__do

__do

__do

Percent

1.0

.7

2.8

Percent 1,000 units 1,000 dollars

0.5 275,000

5,779

8,983

12,576

50,306

77,644

1 Average number of farm chickens and turkeys sold,

and cash receipts from the sales.

2 Average number and cash value of eggs sold

annually.

Edible losses occur in several places along

the processing line :

(1) Preparation losses result from excessive

peeling and trimming; flesh removal v^hen a

fruit is pitted; juices lost through handling;

removal of culls, moldy fruit, and otherwise

undesirable material; and removal of outside

protective leaves. Not considered as edible

losses are peel, stems, caps, pits, and seeds.

(2) Leaching is always a problem with cut

material. Leaching losses can only be guessed

because of inadequate data and variable processing conditions throughout the country.

When water blanching, fluming, or both are

employed, losses are high. Nominal allowances

for leaching losses are included in the tables.

(3) Respiratory losses may occur in any fruit

held before processing. Pears are particularly

TABLE 41.—Estimated average annvM losses

(condemnations) in value occurring during slaughter of livestock and poultry,

1951-60

Species

Losses in value

of

animal Condemned

carcasses

Condemned

parts Total

Calves

Cattle

Goats

Horses

Poultry

Sheep and lambs.

Swine

IfiOO

dollars

1,451

10,963

7

21

6,818

1,271

5,410

IfiOO

dollars

21

1,303

(1)

27

(2)

199

4,611

IfiOO

dollars

1,472

12,266

7

48

6,818

1,470

10,021

Total 25,941 6,161 32,102

susceptible, as they are picked green and

allowed to ripen. Dried fruits held in sweat

boxes until packaging also lose weight. Respiratory and other storage losses are included

in the tables.

Vegefab/e crops

Average annual losses in vegetable crops

during processing are estimated at $19,440,000

(table 39).

Many of the comments relating to fruitprocessing losses are equally applicable to

vegetables. The estimates cover the destruction of edible material during preparation,

leaching losses, and respiratory losses. Pea

and lima bean pods, corn husks, and corn cobs

are not considered edible and their removal

was not included in the estimates.

MARKETING AND PROCESSING POULTRY

AND POULTRY PRODUCTS

During the marketing and processing of

poultry and poultry products, losses result from

TABLE 42.—Estimated average a/nnual losses

(condemnations) to animal livers at

slaughter and meat and meat products during processing, 1951-60

Commodity

Loss in

quantity

Loss in

value

1 Loss of $152.

2 Included in condemned carcasses.

Livers:

Calves 430

Cattle 26,901

Goats 52

Sheep 3,958

Swine 25,519

Total 56,860

Meat and meat products— 18,088

Total 74,948

IfiOO pounds IfiOO dollars

172

10,760

21

1,583

10,208

22,744

5,456

28,200
94 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

several causes, including accidents, lack of care,

disease, deterioration, and spoilage. These

losses represent an estimated average annual

reduction in value of $77,644,000 (table 40).

Market egg defects

Defects such as meat and blood spots occur

in eggs wherever they are produced. Faulty

nutrition is suspected as a factor, as v^ell as

genetics, poor management, and physiological

disturbances. As much as 0.7 percent of the

eggs produced may show these spots.

Other losses arise from factors such as breakage, shell abnormalities, dirt, and spoilage.

Accidents, bruising, and downgrading of poultry

Marketed poultry is subject to downgrading

because of cuts and bruising, poor conformation, discoloration, pinfeathers, and poor condition due to improper management.

MEAT AND POULTRY CONDEMNATIONS

The removal from food channels of unwholesome products and meat from diseased and

abnormal animals is the most important function of the meat and poultry inspection programs. The condemned products include losses

from disease and abnormal conditions identified

during the ante-mortem inspections of livestock

and poultry, the post-mortem inspection of the

carcasses, and the reinspection of the meat products during processing operations at federally

inspected establishments. The estimated average annual losses in value as a result of condemnations during slaughter and processing

are given in tables 41 and 42.
Chapter lO.-Forest Resources and Forest Products Losses

The unsalvaged losse^s of standing timber in

U.S. forests resulting from natural causes are

estimated at about 4,809 million cubic feet annually for the period 1951-60 (table 43). In

terms of sawtimber, the unsalvaged losses from

all natural causes total about 17,015 million

board feet annually. These losses, which represent about 23 percent of the annual growth

of timber crops, result primarily from insects,

fire, disease, and wind, and often are aggravated by natural overstocking and old age

of wild and unmanaged forest stands.

Growth losses due to destruction of seedlings

and saplings, delays in restocking, reduced

growth and increased cull in larger trees, and

deterioration of soils are substantially higher

than losses from natural causes. These losses

are estimated at 6,975 million cubic feet annually, including about 27,870 million board

feet of sawtimber.

Serious losses of lumber and other forest

products in buildings and other structures also

result from fire and other natural causes.

FIRE LOSSES

More than 7 million acres of forest land

were burned over annually in the United States

during the period 1951-60. The volume of

standing timber and trees more than 5 inches

in diameter destroyed by forest fires and not

salvaged is roughly estimated at about 280

million cubic feet annually. Annual losses of

sawtimber due to fires total about 1,069 million

board feet (table 43).

Far exceeding these losses of standing

timber, however, is the loss of current and prospective timber growth on burned-over areas

caused by the destruction of seedlings and

small trees, by deterioration of site quality, by

reduction in growth rates of damaged tree«, and

by increased cull in damaged trees. In the

United States as a whole, the growth loss from

current forest fires is estimated to be more than

5 percent of the potential timber growth. This

constitutes an annual growth loss of about 725

million cubic feet, including about 3,300 million

board feet in terms of sawtimber-size trees.

Annual losses due to forest fires are difficult

to measure. They include the timber destroyed

by fire, possibly amounting to $10,690,000 per

year in terms of stumpage value, and the

timber growth that would have occurred in the

absence of fire, amounting to possibly

$9,900,000. Destruction of timber raw material

may involve lower industrial output and decreased payrolls in forest cummunities. Fires

also reduce hunting and fishing values, lower

yields of usable water, and increase erosion and

flood damage. In some areas the value of

watershed losses far exceeds the direct monetary value of timber or other vegetation destroyed.

A part of the losses from forest fires is attributable to lightning; but smokers, incendiarism, burning of debris, and camp fires

account for most of the damage. Losses from

forest fires undoubtedly can be further reduced

through more effective public education and

more intensive control programs.

Additional losses of lumber, plywood, and

other forest products result from building fires.

The value of lumber and other forest products

lost only in dwellings destroyed by fire is estimated to be about $25,000,000 annually, exclusive of costs of fabrication into buildings,

for the period 1951-60.

INSECT LOSSES

Unsalvaged losses of standing timber more

than 5 inches in diameter from attacks by insects are estimated at about 991 million cubic

feet annually (table 43). In terms of sawtimber, these losses are estimated at about

4,664 million board feet. They reflect the

sporadic outbreaks of bark beetles, some defohators, and the less striking endemic losses caused

by the white-pine weevil, wood borers, and

other forest insects. The monetary value of

losses of standing timber due to insects is

estimated at $46,640,000 annually for the

period 1951-60. . ^. ^

In addition to direct losses of standmg timber

from annual insect attacks, other serious losses,

more diflScult to estimate, arise from reduced

growth, lowered quality of timber, and destruction of forest reproduction. Although outbreaks of defoliators may cause little direct loss

of trees, they reduce tree growth rates to a

point where little wood is produced. Deformities caused by the white-pine weevil and

increased cull due to damage by boring insects

are reflected in lower commercial values of the

timber crop. A large number of aphids, scales,

95
96 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

TABLE 43.—FOREST TREES, NURSERIES, AND FOREST PRODUCTS : Estimated average annual losses

^^^ due to fire, injects, disease, and other cavíes, lOSl-ßO^

Loss from potential production

Kind of loss Reduction Growing

stock 2

Sawtimber 3 Value 4

Forest losses

Fire:

Unsalvaged lossGrowth loss

Percent

Million

cubic feet

Million

hoard feet

Total

Insects:

Unsalvaged loss

Growth loss

Total

Disease:

Unsalvaged loss

Growth loss

Total

Other losses: &

Unsalvaged loss

Growth loss

Total

Total:

Unsalvaged loss

Growth loss

Grand total

Losses in nurseries and

forest jyt^odiicts

Nurseries

Forest products : 6

Insects

Disease

Fire 7

Total

1,000 dollars

280

725

1,069

3,300

10,690

9,900

. - 1,005 4,369 20,590

991

780

4,664

3,580

46,640

10,740

1,771 8,244 57,380

978

4,280

2,969

17,650

29,690

52,950

5,258 20,619 82,640

2,560

1,190

8,313

3,340

83,130

10,020

3,750 11,653 93,150

4,809

6,975

17,015

27,870

170,150

83,610

44 11,784 44,885 253,760

160

500,000

300,000

25,000

825,160

1 All data on annual unsalvaged losses are for 1962.

All other data on annual growth loss and acreage are

for 1952, taken or adapted from "Timber Resources for

America's Future," Forest Resource Report No. 14,

USDA, Forest Service, 1958. Since data are incomplete

for other years, the growth loss data for 1952 are

assumed to represent the trend level growth losses for

the 1950 decade, except for losses caused by fire. Volume

growth lost in 1952 due to fire was adjusted downward

by 50 percent to obtain an estimate more representative

of the trend level during the decade as indicated by the

downward trend in acreage of forest burned between

the decade of the 1940's and the 1950's.

2 Volume growth of growing stock, i.e., in sound live

trees 5 inches and larger in diameter on commercial

forest land.

3 Volume growth (scaled in international ^4-inch log

rule) in sawtimber trees on commercial forest land.

Softwood sawtimber trees are at least 9 inches in diameter except in California, Oregon, Washington, and

coastal Alaska where they are at least 11 inches in

diameter. Hardwood sawtimber trees are at least 11

inches in diameter. Each sawtimber tree contains at

least one saw log.

4 Value of annual board-foot losses in 1963 dollars.

The unsalvaged loss is estimated to have an average

stumpage value of $10 per thousand board feet. The

average stumpage value of growth losses, discounted

to allow for the time period by which the potential

harvest was deferred because of the damaging agent, is

estimated at $3 per thousand board feet. The value for

loss in nurseries is the estimated cost of replacing tree

seedlings lost primarily because of diseases. Values for

losses in forest products are the estimated 1963 market

values of the wood products that are lost (sawlogs,

lumber, etc.) less allowance for depreciation. They do

not include costs of fabricating the wood into furniture

or buildings and other structures after it leaves the

lumber yard.

5 Weather, animals, suppression, and mortality from

unknown causes.

6 Includes losses of logs, lumber, and other forest

products in storage and also losses of wood in use in

furniture and in buildings and other structures.

7 Losses only in dwellings destroyed by fire, based on

Census of Housing showing loss of about 35,000 dwellings annually due to a variety of causes (fire, flood,

condemnation, etc.), of which fire destroys most (possibly 25,000).
LOSSES IN AGRICULTURE

97

and other sucking insects feed on and injure

trees by removing the plant juices. They cause

damage by killing trees, reducing wood production, introducing disease organisms, or making

trees susceptible to secondary pests. Seed and

cone insects sometimes destroy practically all

of a seed crop and prevent regeneration. The

total value of such losses in timber grov^th is

estimated at $10,740,000 annually for the period

1951-60.

Heavy losses of forest products also result

from insect attacks. From the time a tree is

felled until it is finally used in structures, equipment, or furniture products, insects take their

toll. Damage by termites, for example, requires

large amounts of lumber for repairs and replacement. Many millions of dollars are also

spent for treatments to prevent termite damage. Ambrosia beetles and other wood borers

attack green logs and lumber, causing losses

during processing, storage, and use. Pulp logs

are subject to attack, and heavy losses occur in

storage. Powder post beetles also attack stored

lumber, furniture, and other wood products.

Altogether, product losses due to insects for

the period 1951-60 are estimated at about

$500,000,000 annually excluding any costs of

fabricating lumber or other products for final

use in furniture, or in buildings and other

structures (table 43).

DISEASE LOSSES

Unsalvaged losses of standing timber in

trees more than 5 inches in diameter due to

forest diseases are estimated at about 978

million cubic feet annually, including 2,969

million board feet of sawtimber (table 43).

Heavy damage occurs year in and year out from

attacks by many kinds of diseases, including

bark canker fungi, wilts, rusts, and viruses.

Root rots also reduce growth and make trees

susceptible to attacks by insects or subject to

windthrow.

Losses due to reduced growth and lowered

quality because of disease are far greater than

losses of standing timber. Heart rots are of

particular importance, since they attack all

species of timber and cause heavy losses in the

form^ of cull and lowered quality of the re

maining wood. These growth losses total an

estimated 4,280 million cubic feet annually in

eluding about 17,650 million board feet of sawtimber. Annual losses caused by forest diseases

for the period 1951-60 amount to possiblv

$82,640,000 of which $52,950,000 represents

growth loss and $29,690,000 loss of standing

timber.

Heavy losses of forest products also result

from decay of wood in use and storage. Decay

in buildings and other structures arising from

improper construction, lack of wood preservation, and other factors requires replacement of

the damaged wood and involves labor and other

costs that far exceed the market value of the

destroyed wood. Some sawlogs and pulpwood

in storage are also lost to decay. The estimated

average annual value of such losses is approximately $300,000,000 for the period 1951-60

(table 43).

OTHER LOSSES

Unsalvaged losses of standing timber in

trees more than 5 inches in diameter from windthrow, animals, suppression, or other causes

amount to an estimated 2,560 million cubic feet

annually, including 8,313 million board feet of

sawtimber. The average annual value of this

unsalvaged loss is roughly estimated at about

$83,130,000 for the period 1951-60 (table 43).

In many areas, reduction of timber growth

and future yields as a result of rodents is more

serious than the direct loss of standing timber.

Mice and other animals consume large quantities of seed of important species such as

ponderosa pine, preventing their reproduction

and thereby encouraging invasion of worthless

brush. Damage to live timber by porcupines,

deer, and other animals also causes losses in the

form of reduced growth, lowered quality, and

delayed regeneration amounting to about 1,190

million cubic feet annually, including about

3,340 million board feet of sawtimber. These

cumulative losses from damage are estimated

at approximately $10,020,000 annually for the

period 1951-60 (table 43).
Chapter 11.-Soil and Water Losses

EROSION, WATER, AND UNFAVORABLE SOIL

CONDITIONS

Nature of agricultural losses

Estimating agricultural losses due to soil deterioration, and more specifically to erosion, excess water, and unfavorable soil conditions,

presents difficulties not encountered in estimating direct losses such as those caused by

crop diseases, insects, hail, and fire. Year-toyear losses inflicted on growing crops by floodwaters, sediment deposition, and soil erosion

are tangible; although these losses have not

been regularly tabulated, a somewhat firm basis

for estimating their magnitude exists. Physical

damage to or loss of the resource itself is much

less tangible. Not only is the magnitude of such

losses difficult to estimate, but placing dollar

value on them is even more uncertain.

In this discussion, consideration is given

primarily to losses that arise essentially from

physical soil deterioration. These losses include

erosion by runoff water, blowing (wind erosion), unfavorable soil conditions, alkali accumulation, waterlogging, floodwater, sediment, and related watershed damage ; they are

assumed to be preventable. Not included are

losses of organic matter and replaceable plant

nutrients that are the normal result of crop

production.

Additional agricultural losses involving cropland, which are not considered here, include extensive areas deliberately inundated by permanent dam backwaters and the estimated

410,000 acres of cropland absorbed annually

by urban and industrial expansion, by highway

and airport construction, and by recreation

facilities. Nor is consideration given here to

areas where low soil productivity is a natural

consequence of an original state of infertility,

drought, or climatic conditions.

Computation Procedure.—The following

basic data and estimates were used to calculate

the losses of soil and water :

(1) Acreage of crops harvested and their

value for each State.^

(2) Estimates by the Agricultural Research

Service of productivity lost per acre and the

years that the land has been subject to hazards

noted under the three categories in item 3.

1 U.S. CENSUS OF AGRICULTURE, 1950, 1954, and 1959.

(3) Acreage of cropland needing treatment ^

where—

(a) dominant problem is erosion,

(b) dominant problem is excess water, or

(c) dominant problem is unfavorable soil

conditions.

From these data, the annual rate of loss in

dollars was capitalized at a 4-percent interest

rate to arrive at its present worth. This capitalized value is the average annual loss. It was

estimated on a State-by-State basis, and the

totals for the three categories as given [under

items 1, 2, and 3] in table 44. Estimates of

losses from floodwater, sediment, and related

watershed damage in table 44 were prepared

by the Soil Conservation Service.

Economic Evaluation of Losses.—Although

there is no satisfactory method for evaluating

physical soil deterioration on cropland on a

national scale, various estimates have been

made. The annual losses from erosion alone, in

terms of the cost of replacing through commercial fertilizers the major nutrient elements

removed through soil erosion, have been estimated at several billion dollars. The cost (at

1960 prices) of replacing only the nitrogen

and phosphorus is estimated by investigators

of the Department at $4.3 billion, and of replacing the nitrogen, phosphorus, and onefourth of the potassium at $7.75 billion. This

does not include, however, large supplies of

these nutrients uncovered in many soils by both

natural and accelerated erosion. The estimated

annual losses (table 44) for wind and water

erosion on cropland are about $800 million, on

grazing land $150 million, and on forest land

$16.5 million—a total of about $967 million. If

the estimates of $291 million for losses due to

excess water and of $353 million for unfavorable soil conditions are included, the total approaches $1.6 billion.

The total value of U.S. farm real estate

ranged from about $86 billion in 1951 to $130.2

billion in 1960.^ The average for the period

1951-60 is about $108 billion. On the basis of

|;his figure, the $1.6 bilHon loss is equal to about

\J 2 CONSERVATION NEEDS INVENTORY COMMITTEE OF THE

U.S. DEPARTMENT OF AGRICULTURE, NATIONAL INVENTORY OF SOIL AND WATER CONSERVATION NEEDS. U.S.

Dept. Agr. Statis. Bui. 317, 1962.

»ECONOMICS RESEARCH SERVICE, U.S. DEPARTMENT

OF AGRICULTURE, FARM REAL ESTATE MARKET DEVELOPMENT, CD 61. June 1962.

98
LOSSES IN AGRICULTURE 99

TABLE 44.—SOIL AND WATER : Estimated average annvxil losses due to different causes and

cost of controlling these losses, 1951-60

Kind of loss

Average

annual

loss

On cropland acreage needing treatment

where doniinant problem is due to—

1. Erosion by wind or water or both i

2. Excess water (high water table or

temporary flooding) i

3. Unfavorable soil conditions (salinity, alkalinity, deterioration of

soil structure, etc.)

Annual flood damage for upstream and

downstream areas:

4. Floodwater, sediment, and related

watershed damage i

On other lands :

5. Forest land erosion by wind or

water or both

6. Rangeland erosion by wind or water

or both

Water losses due to—

7. Irrigation

8. Evapotranspiration—

On cropped acreage

On fallow acreage

Total losses

Cost of controlling losses

Grand total

1,000

dollars

800,325

291,000

353,050

1,345,454

16,500

150,000

665,000

166,000

38,000

3,825,329

238,080

4,063,409

1 These items have been adjusted to eliminate double

counting.

11/2 percent of the average value of farm real

estate.

However, annual losses of ly^ percent of the

dollar value of farm real estate does not implythat v^ithin 75 or 100 years the value will approach zero. With appropriate antideterioration measures, many of these losses can be

prevented.

Erosion

Erosion on Cropland.—Estimated average

annual losses of about 800 million dollars are

attributed to soil erosion by water or wind or

both from croplands in the United States for

the period 1951-60 (table 44). From the standpoint of physical deterioration of land, erosion

undoubtedly causes greater damage than any

other factor. Soil erosion has forced the

abandonment for cultivation of an estimated

35 million acres of land that were originally

suitable for crop production.

Water erosion and the accompanying sedimentation in the low-lying areas, valley lands,

and reservoirs constitute a continuing threat

to the land and water resources of this country.

The physical removal of productive topsoil from

cropland and grassland by sheet erosion

amounts to many millions of dollars annually

Sedimentation attendant to soil erosion causes

untold damage by covering up growing crops

reducing the productivity of good agricultural

land, and reducing the effectiveness of water

reservoirs.

For example, experiments conducted by research workers at the Midwest Claypan Soil

Conservation Experiment Farm in Missouri

showed that reduction in crop yields per inch

of surface soil lost through erosion was as

follows :

Bushels

Crop 'pQy dßrpQ

Oats in south Missouri 5

Corn in north Missouri 4

Soybeans on claypan soils :

Without fertilizer 1.5

With fertilizer 2.7

These losses in production indicate that in

Missouri, in the places and under the conditions existing where the studies were made,

namely on a claypan soil, a 100-acre farm with

slight erosion became equal to only an 80-acre

farm when it reached the stage of moderate

erosion. It was equal to only 50 acres when it

suffered severe erosion by loss of more than

half of the original surface.

Although few reliable figures are available

on the areas affected by soil blowing (wind

erosion), it may be assumed that at least 75

million acres are subject to this type of loss.

Perhaps 36 million acres need treatment and

10 million acres are seriously affected.

The effects on crop yields of losses from wind

erosion are similar to losses from soil erosion

caused by runoff water. The most fertile parts

of the soil are removed, conveyed in the air for

considerable distances, and then deposited on

the land, in cities and towns, or in the sea.

Much of the soil removed is redeposited on

farmland, where it remains available for use.

However, much of it is deposited where no

use can be made of it or where it creates major

problems of removal. Dust storms, which represent severe soil blowing, cause additional

damage through abrasive action on crops, machinery, and farm equipment.

Losses from soil blowing are generally

limited to arid and semiarid areas but are

widely distributed. Losses are greatest in the

Great Plains States. Soil blowing in the humid

areas, although less serious, does create acute

local problems, particularly on drained and

cultivated organic soils (peat and muck) and

on very sandy soils.

Wind erosion is a major land management

problem on lands in the Great Plains; it becomes acute during extended drought periods.
100 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

The immediate effect of wind erosion is on the

surface crust. However, prolonged erosive

winds—lasting a month or more—tend to reduce the quantity of crop residue, soil cloddiness, and surface roughness. Therefore, a

gradual deterioration in resistance of surface

to erosion by wind may be expected.

Erosion on Grazing Land (Pasture and

Range).—The National Inventory of Soil and

Water Conservation Needs estimates that in

the 50 States 72,380,000 acres of grazing land

need a vegetative cover established or reestablished. However, 44,768,000 acres of this land

are coming into grazing from other uses, so

no current loss to agriculture can be estimated

under the grazing use. This leaves a total of

27,612,000 acres of grazing land that are

presently inadequately vegetated. Much of this

acreage is subject to erosion.

Land having a dominant problem of erosion

makes up slightly more than half (53.6 percent) of all land classified as pasture and range

in the Inventory. If this proportion applies to

the acreage inadequately protected by vegetation, about 14,800,000 acres in the 50 States

may be subject to active erosion. The Inventory

includes 32,065,000 acres of pasture and range

needing erosion control measures in addition

to those that need a vegetative cover. Soil

losses, therefore, may be occurring on a total

of 46,865,000 acres of land in pasture and

range.

The estimated annual loss for wind and water

erosion on grazing land (pasture and range)

is $150,000,000.

Erosion on Forest Land.—The National Inventory of Soil and Water Conservation Needs

estimates that 12^/4 million acres (1 acre out of

36) of non-Federal forest land need protection

from erosion. Included is acreage that should

be converted to forest because of serious erosion

damage that occurred when the land was in

some other use. Also included is present forest

acreage with active wind or water erosion.

Much of this erosion is in connection with the

concentration of water along forest roads,

skid trails, and other structures. Estimated

losses resulting from decreased productivity,

damage to growing stock, and increased cost

of establishing trees or management if erosion

is not controlled average about $1 per acre annually on this land, or a total of $12,350,000.

If preventable erosion on Federal forest land

is assumed to be only half that on non-Federal

forest land (or 1 acre out of 72), the total cost

of erosion on forest land is $16,500,000.

Excess wafer

Estimated average annual losses to croplands

due to excess water for the period 1951-60 were

$291,000,000 (table 44). These losses result

from a high water table or from temporary

flooding that prevents or limits use of conservation farming systems. According to the National Inventory of Soil and Water Conservation Needs, excess water is the dominant

problem on 94 million acres of cropland, of

which 60 million acres need treatment.

Poor drainage on much of the good land in

the humid part of the country is a continuing

threat to the productivity of the land affected.

Waterlogging, salinity, and alkalinity are

component parts of a severe threat to the longtime productivity of irrigated lands of the

Western United States. Detailed data showing

relation of land-use changes to major soil

problems are available in the Inventory for

about 7.4 million acres of irrigated cropland

in nine Great Plains States. These figures,

when expanded to the entire acreage of irrigated cropland in the 17 Western States and

Hawaii, indicate that about 85,000 acres of irrigated land having a dominant problem of

excess water will be converted to pasture and

range and to other land uses between 1958 and

1975, or about 5,000 acres annually. It can be

assumed that this is land being taken out of

cropland because of waterlogging. There probably are losses caused by decreased yields on

areas where the condition is less severe and the

land is not retired from cultivation. The Inventory shows that possibly 4,000,000 acres

of cropland in these States need treatment to

alleviate the effects of excess water.

Floodwater, Sediment, and Related Watershed Damage.—Floodwater, sediment, and

related watershed damage cause heavy economic losses to agriculture in the United States

each year. These losses include damage to

crops and pasture; land damage in the form

of gully and other channel erosion, flood plain

scour, swamping, infertile overwash, or other

kinds of sediment deposition; damage to farm

buildings, fences, farm roads, stored crops,

livestock, and irrigation and drainage facilities; and indirect losses such as those occasioned by delays in fieldwork and disruption or delays in marketing of farm products.

Some of these losses are as follows :

Upstream agricultural flood damage :

Damage to crops and pastures $484,472,000

Sediment damage 88,819,000

Other damage 234,163,000

Total 807,454,000

Downstream flood damage areas: "

Downstream agricultural damage 179,000,000

Downstream nonagricultural damage _ 359,000,000

Total 538,000,000

Total upstream and downstream '

losses 1,345,454,000
LOSSES IN AGRICULTURE 101

The estimate of annual flood losses is made

for ''upstream" drainage areas of less than

390 square miles and for "downstream'' drainage areas of more than 390 square miles. These

estimates are based on data developed by the

Soil Conservation Service in connection with

the preparation of watershed work plans under

the Watershed Protection and Flood Prevention

Act (Public Law 566, as amended). Data from

361 watersheds covering about 31 million acres,

in 46 States, were expanded by physiographic

regions to estimate the total for the United

States.

The Corps of Engineers estimated flood damage in downstream areas for 1957 conditions.^

This estimate was not divided between agricultural and nonagricultural damage. However, Sanders and Black in 1958 estimated that

about one-third of downstream damage was

agricultural and two-thirds nonagricultural.^

On this basis, it is apparent that about $179

million of the average annual downstream damage is agricultural and $359 million is nonagricultural. The available information is not

adequate to determine downstream agricultural

losses by types of damage or physiographic

regions.

Flood plain damage by scour, channel erosion,

gullying, and valley trenching is important

monetarily and also from the viewpoint of our

agricultural resources. About 6 percent of our

total agricultural land lies in the alluvial flood

plains of tributary valleys.^ In general, this

land is highly productive and if given flood

protection, it will remain so for use by future

generations. Some land damage is temporary;

and proper treatment may restore productivity.

The treatment, however, may prove costly.

Irrigation Water,—Figures in Geological

Survey and Census reports ^* ^' ^ show that the

actual plant needs for irrigation water average

about 0.8 acre-foot per acre in the humid,

eastern part of the United States, and 1.5 acrefeet per acre in the Western United States. To

provide this water to the plants it was necessary to deliver to the farm 1 acre-foot in the

East, and 2.8 acre-feet in the West. i

4 SELECT COMMITTEE ON NATIONAL WATER RESOURCES,

UNITED STATES SENATE, FLOODS AND FLOOD CONTROL.

Com. Print No. 15, 86th Cong., 2d Sess., 1960. ^

6 SANDERS, T. J., and BLACK, N. S. WATER: PARTNERSHIP TO MANAGE WATER. In Land, 1958 Yearbook of

Agr., p. 349. 1958.

6 See footnote 2.

7 U.S. CENSUS OF AGRICULTURE: 1959. Vol. III. IRRIGATION OF AGRICULTURAL LANDS. Washington, 1962.

8 U.S. CENSUS OF AGRICULTURE: 1959. Vol. V, Special

Reports, Part 2. IRRIGATION IN HUMID AREAS. Washington, 1960.

9 MACKICHAN, K. A., and KAMMERER, J. C. ESTIMATED

USE OF WATER IN THE UNITED STATES, 1960. U.S. Dept.

Int., Geol. Survey Cir. 456, 1961.

Thus, in 1959 with 2.2 million acres of ir

rigated land in the East, 0.44 miUion acre-feet

of water were lost and similarly in the West

with 31.5 million acres, 32.8 million acre-feet

were lost. In terms of dollars, if the very conservative figure of $20 per acre-foot is used,io

these losses would amount to about $665,000,000

annually.

Also it is apparent, if this loss could be eliminated entirely, the acreage of irrigated land

could be increased by from 60 to 70 percent.

Assuming that this reduction in water

handled is a measure of a cost that is preventable by known methods, and that $1.50 per

acre-foot is a reasonable cost-of-handling

figure, the preventable cost of handling excess

irrigation water amounts to $84,284,730 annually.

The U.S. Geological Survey estimated that in

1960, 103 million acre-feet of water were withdrawn to irrigate 33.7 million acres of land

in the United States. Of this amount, 90 million acre-feet were actually delivered to the

farms and 22 million acre-feet were lost in

conveyance. In its report to the Senate Select

Committee on Water Resources, the U.S. Department of Agriculture estimated that average

farm efficiency in the use of water was 47 percent, but that 55 percent of the total losses could

be recovered for reuse.^^

fvapofronsp/raffon

Evaporation loss from soil surfaces is undoubtedly the greatest loss of water to agriculture. Of the water that reaches the root

zone under irrigated conditions, up to 50 percent is estimated to be lost by evaporation from

the soil surface. There is evidence also to indicate that in the Midwest, where frequent

summer showers occur, as much as 50 percent

of the total water lost in a season can be accounted for by evaporation from the soil surface. In the Great Plains as much as 65 percent of the total water falling is lost by evaporation.

The assumption that 50 percent of the annual évapotranspiration is lost from cropped

acreage is conservative, considering the high

losses incurred from irrigated lands and the

losses during intervals between crops. Assuming an average of 15 inches annual évapotranspiration, evaporation losses would amount

to about 100 million acre-feet of water or about

$166,000,000 (table 44) on the 170 milhon

10 WOLLMAN, NATHANIEL, and others, THE VALUE OF

WATER IN ALTERNATIVE USES. Univ. of NeW MeXlCO

Press, Albuquerque, 1962.

11 SELECT COMMITTEE ON NATIONAL WATER KEsouRCES, UNITED STATES SENATE, WATER RESOURCES

ACTIVITIES IN THE UNITED STATES. Coni. Print No. \¿i

86th Cong., 2d Sess., 1960.
102 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

cropped acres (exclusive of summer-fallowed

land) in the 17 Western States.

Assuming a conservative estimate of 14

inches annual precipitation on 28 million fallow

acres and a seasonal loss of 70 percent of this

precipitation, the annual loss by evaporation

would be about 23 million acre-feet of water,

amounting to about $38,000,000 (table 44).

Some of this loss is preventable.

^ Therefore, the total annual évapotranspiration loss of water from both cropped and fallowed acres would amount to $204,000,000.

Physical information to estimate surface

evaporation losses from range, forested, and essentially nonvegetated (desert and alpine)

lands is largely lacking. Grasses that provide

complete cover should considerably reduce

evaporation from the soil surface as compared

to cultivated crops. However, in western range

areas, complete cover is seldom attained because of sparse vegetative growth or the low

growth habit of much of the vegetation. In addition, either natural or drought-induced

dormancy occurs for extended periods on large

acreages. Forested and brush-covered land

similarly do not provide complete cover.

Neither beneficial plants nor effective cover

occurs on major western land areas. Thus,

evaporation from the soil surface is undoubtedly a serious source of water loss from

range, forested, and nonvegetated lands.

Evaporative losses from the 600 million acres

of rangeland, 250 acres of forested land, and

100 million acres of desert and alpine land probably greatly exceed the combined losses from

fallow and cropped land.

The relative magnitude of soil evaporation

and transpiration cannot be established as a

precise ratio, since the magnitude of each depends on the relative wetness of the surface.

In row crops, sufficient energy reaches the

ground surface to account for a considerable

portion of the water loss. The absolute amount

of water loss, however, depends on the time the

soil surface is wet and on the moisture-holding

and transmitting capacities of the soil. It

would be virtually impossible to predict the

absolute amount of soil evaporation.

Unfavorable soil conditions

Losses due to unfavorable soil conditions have

been estimated at $353,050,000 (table 44). Unfavorable soil conditions include salinity,

alkalinity, acidity, low moisture-holding capacity, or some other condition that limits

root development. Many of the losses due to

these specific conditions are difficult to evaluate,

but nevertheless they are large enough to be

important economically.

Salinity,—Soil deterioration from the accumulation of deleterious salts may follow the

application of salty irrigation water, inadequate development of drainage, or both. It is

limited largely to the irrigated Western States.

In a study of some 30 million acres, more than

8 million acres were affected by accumulations

of saline elements. Saltiness ranges from a low

level that allows most crops to grow well to

levels so high that no crops can be grown.

However, some plants can tolerate much more

salt than others. Always present with salinity

is an increase in osmotic pressure of the soil

solution. This restricts water uptake by the

plant and reduces growth. Toxic effects associated with specific ions also occur and cannot be neglected.

Qualitatively, the effects of salinity on crop

yields are hard to measure. One index used

widely is to relate crop response to the electrical conductivity of saturation extracts of soil

water.

In addition to the toxic effects of salt concentrations on growth and yield of the plants,

alkali accumulation frequently leads to deterioration of the physical structure of the

soils ; they become impermeable and untillable.

This circumstance is usually accompanied by

waterlogging of the soil. Furthermore, the

actual waterlogging due to excess irrigation,

even with relatively mineral-free water, often

brings to the root zone toxic salts hitherto found

only in the subsoils. Unlike losses due to severe

soil erosion, losses arising from alkali accumulation and waterlogging are generally reversible.

Deterioration of Soil Structure.—While loss

of favorable structure frequently accompanies

soil erosion through the exposure of harsh,

cloddy subsoils, it is also a widely prevalent

consequence of cultivation even where no soil

is lost. Yield reductions may be permanent in

the absence of proper soil management, but

generally the condition can be corrected through

a shift to fewer and more careful cultivations

and better rotations. Poor structure may develop at the surface (surface crusts), below the

furrow slice (plow or tillage pans), or within

the surface soil (puddling and compaction).

Hard surface crusts develop mainly from the

beating of raindrops on unprotected soil. Adverse effects on crops arise from (1) impedence

of water infiltration with consequent increase

in runoff and erosion, (2) interference with

seedling emergence, and (3) injury to young

plants during cultivation.

Plowpan formation is a frequent result of

overcultivation of moist, medium-textured soils

with implements whose blades tend to compact

the soil immediately below the furrow slice.

Plowpans affect crop yields through resistance
LOSSES IN AGRICULTURE 103

to root development and reduction in water permeability.

Puddling and compaction of the surface occur when soils are driven over or cultivated

while still moist. The result is reductions in

yield from the unfavorable seedbed produced.

The hoofs of grazing livestock may also cause

some compaction.

Structure deterioration occurs in varying

degrees throughout the country. The most

severe damage to crop production is generally

on the medium-textured soils, particularly silt

loams, but many areas of heavy soils are susceptible, such as the lake plain soils of northern

Ohio. Damage is frequently less severe in

regions where heavy frosts are common. Damage due to the formation of surface crusts is

most pronounced in sandy loams and silt loams.

WEEDS IN AQUATIC AND NONCROP

AREAS

Weeds in and along irrigation canals and

ditches of the 17 Western States obstruct the

flow of water; increase evaporation and seepage losses; cause sedimentation, canal breaks,

and damage to structures; prevent timely

delivery of water to crops; result in large

losses of water through transpiration; clog

sprinkler heads, valves, and structures; and

interfere with efficient operation and maintenance of the irrigation systems. Weeds in

drainage ditches cause similar losses and, in

addition, result in damage to crops from inadequate drainage and infestation of farmland

from weed seeds produced along the ditches.

Weeds in farm ponds and reservoirs interfere

with using the ponds for such things as water

storage, irrigation, fish production, and recreation. The estimated average annual losses in

value of irrigation water and related resources

due to weeds in aquatic and noncrop areas are

given in table 45.

Because of lack of suitable control methods

for many weeds in aquatic and noncrop areas

in the 17 Western States, losses from weeds

have remained high. The losses would be much

higher if the value of irrigation water lost were

considered at its net productive value of $20

per acre-foot instead of the average cost of

$2.09 per acre-foot. Also, the losses tend to

increase every year as more farm ponds, drainage ditches, and irrigation canals are constructed and become infested with weeds, and

as the needs for water and the movement of

water through canals and streams become more

critical for agriculture, navigation, industrial

and urban development, and recreation.

TABLE 45.—IRRIGATION WATER AND RELATED

RESOURCES: Estimated average annual

losses from weeds in aquatic and noncrov

areas, 1951-60

Kind of loss

Average

annual

loss

1,000

dollars

Losses of water due to weeds in—

Irrigation systems (17 Western States) __ 14,110

Farm ponds and reservoirs 27,320

Ditchbanks of drainage ditches

(31 Eastern States) 8,550

Watershed and drainage basins

(17 Western States) 9,750

Total losses due to aquatic plants 49,730

Losses on noncrop areas:

Fencelines 650

Damage to canals, structures, and farms, 2,110

Total losses due to weeds in noncrop

areas 2,760

1 Computed at an average cost of $2.09 per acre-foot

of water. On the basis of data by Wollman and others

(footnote 11), $20 per acre-foot is a very conservative

figure for the cost of irrigation water. On this basis,

the estimated loss of irrigation water would be

$39,332,700.

Western ¡rrigafion systems

The most troublesome aquatic weeds in irrigation and drainage canals of the West are

pondweeds, elodea, filamentous algae, cattail,

and bulrushes. Bank weeds that cause the

greatest losses include reed canarygrass, johnsongrass, Carex, Canada thistle, and many other

rank-growing herbaceous and woody species.

A joint survey 12 in 1957 conducted by the

Agricultural Research Service and the Bureau

of Reclamation showed that aquatic and ditchbank weeds on irrigation systems in the 17

Western States cause annual losses of 1,966,000

acre-feet of irrigation water at a cost of

$4,110,000 and result in other losses of

$2,110,000 (table 45). This water, if available,

would be enough to irrigate 330,000 to 780,000

acres of cropland, depending on the length of

the growing season, evaporation losses, and

other factors.

Eastern dramage ditches and water control canals

According to 1949 Bureau of Census estimates, there are nearly 190,000 miles of open

drainage ditches and irrigation canals m the

31 Eastern States. The aquatic weed problems

in these channels are similar to those in western

irrigation systems, but bank weed problems are

12 TiMMONS, F. L. WEED CONTROL IN WESTERN IRRIGATION AND DRAINAGE SYSTEMS. U.S. Dept. Agi., Agr. ReS.

Service, ARS-34-14, 1960.
104 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

often more serious because of denser and ranker

growth resulting from greater rainfall and

longer growing seasons. Weed species that are

more troublesome in canals and ditches in

Eastern States than they are in Western States

include naiad, milfoil, waterhyacinth, waterprimrose, alligatorweed, paragrass, and phragmites.

Weed growth in and along drainage ditches

and water control canals in the East is generally greater than along irrigation and drainage

canals in the West, but estimated annual losses

from weeds in the East were only $45 per mile

as compared to annual losses of $43 per mile in

the 17 Western States. The estimated average

annual loss along drainage ditches of irrigation

systems in 31 Eastern States is $8,550,000

(table 45).

Farm ponds and reservoirs

According to the 1954 Census of Agriculture,

there are 1,768,000 farm ponds in the United

States. These ponds average approximately 1

acre in size. Serious weed problems exist in

50 to 70 percent of these ponds. The weeds

greatly reduce the storage capacity of water for

livestock, irrigation, and fire protection, and interfere with fishing, boating, swimming, and

other uses. Weeds that most commonly interfere wth economic utilization of ponds and reservoirs include naiad, milfoil, elodea, coontail,

waterlilies, waterhyacinth, waterlettuce, waterprimrose, cottonball, and filamentous algae.

The average annual loss from weeds in farm

ponds for the period 1951-60 is estimated at

$27,320,000.

Undesirable phreafophyfes

Saltcedar, willows, cottonwoods, seepwillow,

greasewood, and other undesirable phreatophytes that grow on river ñoodplains, along

canals and streams, and around irrigation reservoirs are estimated by the U.S. Geological

Survey ^^ to result in water losses of 20 to 25

million acre-feet annually. That agency has

estimated that more than 4.5 million acre-feet

of this wasted water could be successfully and

economically salvaged and delivered to farms

and cities for irrigation and other uses. The

value of this salvageable water at the average

cost of $2.09 at the water user's headgate

would be $9,750,000. In addition to the tremendous water losses, phreatophytes cause

ñood damage, sedimentation, and other losses

not accounted for in this report.

Weeds in fencelines

The amount of farmland occupied by fencelines in the United States varies from 0.6 to

0.9 percent as much as the cultivated cropland

in different sections of the country, and totals

more than 2,000,000 acres or nearly 5,000,000

miles of fencelines. Weeds in fencelines include

many that are hazardous to humans and livestock. Also, they harbor harmful rodents, insects, and plant diseases, and result in damage

to fences when dry weeds are burned. Estimates of these losses have been included in

other sections of this report, with the exception of losses in fencelines due to burning

weeds. This is estimated to be $650,000.

13 ROBINSON, T. W. PHREATOPHYTES. U.S. Geol. Survey

Water-Supply Paper 1423, 84 pp., illus. 1958.
Chapter 12.-Costs of Controlling Losses and of

Inspection and Quarantine Services

Diseases, insects, and pests not only reduce

the quantity and quality of crops, livestock, and

other agricultural products; they also increase

the cost of production because of the need to

apply measures for their control. The packer

of meats and poultry and their products for

interstate commerce must assure by Federal

inspection that these products are wholesome.

Federal-inspection costs and the costs of controlling insects, pests, and weeds ultimately

aiïect the consumer. These costs may be

grouped under five major categories: (1)

chemical control measures, (2) cultural and

mechanical practices, (3) biological control

measures, (4) large-scale cooperative control

programs, and (5) inspection, quarantine, and

regulatory measures. The first three categories

relate to the production and marketing of crops

and livestock.

Many losses that occur during the production

and marketing of crops, livestock, and forest

trees can be reduced or eliminated by agricultural chemicals. Other control measures include

sanitation, management practices, and use of

biologies.

Nationwide control, eradication, and regulatory programs protect agriculture from destructive insects, nematodes, and plant and

animal pests. The Federal meat and poultry

inspection programs assure that meat and

poultry and their products will be clean, sound,

and wholesome for human consumption, free

from adulteration, and truthfully labeled.

Other efforts to control destruction or reduced quality of agricultural products include

the inspection of plants and animals at ports

of entry. This service is aimed at excluding

the entrance of pests and diseases that affect

both crops and livestock and that are not now

in the United States.

All of these control measures and various

services are costly. These costs affect the producer or marketer in some instances, but in

the end all affect the consumer. It is the purpose of this chapter to record some of the costs

of controlling pests of crops and livestock and

the costs of maintaining the various Federal

services for the inspection and protection of

these commodities.

ANIMAL-DISEASE ERADICATION PROGRAMS

Nationwide animal-disease control and eradication programs to protect the livestock industry are conducted in cooperation with State

and local agencies. These programs are administered to prevent the spread of diseases

through interstate shipments of livestock and

poultry.

The average annual cost of the cooperative

animal-disease eradication programs is $47,-

577,693 (table 46). The federally sponsored

part of these programs is $20,393,149.

TABLE 46.—COOPERATIVE ANIMAL-DISEASE ERADICATION PROGRAMS : Average anmml cost, 1951-60

Program or

activity 1

Average annual cost

Federal Non-Federal Total

$13,052,369 $14,695,020

557,893

1,637,685

358,376

5,064,312

1,136,151

2,682,547

1,052,560

$27,747,389

172,035

1,755,787

408,477

1,965,225

1,594,105

323,078

1,122,073

729,928

3,393,472

766,853

7,029,537

2,730,256

3,005,625

2,174,633

20,393,149 27,184,544 47,577,693

Brucellosis (7 years)

Scabies (7 years)

Screw-worm (3 years)

Ticks (7 years)

Tuberculosis (7 years)

Vesicular exanthema (6 years)-

Miscellaneous diseases (7 years)

Interstate movement (7 years) —

Total

1 Federal programs for the period 1951-60, except screw-worm (3 years) and vesicular exanthema (7 years);

non-Federal programs as indicated.

105
106 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

ANIMAL INSPECTION AND QUARANTINE

PROGRAMS

The primary objectives of the animal inspection and quarantine programs are (1) to

prevent the introduction of foreign animal and

poultry diseases into the United States through

a system of inspections and quarantines at

ports of entry to determine freedom from diseases of animals, poultry, animal products, and

associated materials imported from many foreign countries; (2) to insure continuing export

trade in livestock and products by health inspections and certifications at origin and at

ports of embarkation; (3) to make certain that

all veterinary biologies such as serums, vaccines, and related products used in the prevention and treatment of livestock and poultry

diseases are pure, safe, and potent.

Animal quarantine measures

Inspection and Qimrantine at Ports of Entry,—Animals and poultry, v^hich each year are

brought into the United States for various purposes from many foreign countries, can bring

with them several diseases that presently do

not exist in this country—foot-and-mouth disease, rinderpest, contagious pleuropneumonia,

African swine fever, fowl plague, and many

others. They can also harbor diseases already

present—such as brucellosis, tuberculosis, hog

cholera, and Newcastle disease—and thereby

complicate nationwide control and eradication

programs.

To provide for orderly importations of animals and poultry, the principal coastal cities

and various points along international land borders are designated as ports of entry. At some

ports inspection service is provided by resident

inspectors while at others inspection service is

on an appointment basis. Health inspection of

import animals and poultry is mandatory by

law. Adequate inspection and quarantine has

taken on added significance with increased use

of air transportation.

Each year thousands of tons of animal byproducts such as hides, wool, bones, animal

glands, and dried blood are imported for pharmaceutical and industrial uses. Such products

are potentially dangerous from a disease-introduction standpoint and must be inspected at

ports of entry and released without restrictions

if this can be safely done; otherwise, the products are sent under seal to approved industrial

establishments for handling and processing

under supervision in a manner designed to

preclude spread of disease.

The purpose of regulatory controls over export livestock is to foster and maintain foreign

trade by assuring that only healthy animals

are shipped to foreign countries and in a manner that will assure their arrival in good

condition. Thus there are health requirements

to be complied with and requirements on transporting vessels and aircraft as to space, ventilation, feed, water, and attendants.

The average annual cost incurred in the administration of laws and regulations relating

to the importation and exportation of animals

and products and maintaining surveillance at

ports of entry is $748,000 (table 47).

Operation of USDA Animal Qvxirantine Station, Clifton, N, J.—The station is maintained

for quarantine or other detention of authorized

importations of animals and poultry. Department veterinarians perform diagnostic tests,

administer precautionary treatments for parasites as required, conduct daily health examina^

tions, and supervise the care, feeding, and handling of animals and birds during their quarantine. Upon completion of minimum quarantine

periods and if the animals are free from evidence of infectious or communicable diseases

and exposure thereto, they are released to

owners without further restrictions except for

certain animals subject to permanent postentry requirements at approved zoological

parks. No charges are made for inspection

services. Rates have been established for the

care, feed, and handling of animals and poultry

while in quarantine and for normal maintenance of the station. This represents an average annual cost to importers of $23,000 (table

47).

Inspection and Certification of Inedible Animal Products.—Regulations authorizing the

Secretary of Agriculture to assist in the develTABLE 47.—ANIMAL INSPECTION AND QUARANTINE SERVICES AND PRODUCTION AND MARKETING OF VETERINARY BIOLOGICS: Average

annual cost

Nature of cost

Average

annual

cost

IfiOO

dollars

Animal quarantine measures:

Inspection and quarantine at ports

of entry 748

Operation of USDA

Quarantine Station, Clifton, N.J 23

Inspection and certification of

inedible products 115

Controls over the production and marketing

of veterinary biologics :

Licensing and inspection 540

Assessment fee for Control Agency 32

Total 1,358

Service inaugurated July 23,1955.
LOSSES IN AGRICULTURE 107

opment of new or expanded markets (foreign

and domestic) provide for an inspection service

whereby the Department, upon request, mayissue and endorse certificates that meet certain

specifications of contracts for the purchase or

sale of animal byproducts, or to accompany

shipments that meet the requirements of receiving foreign countries. Prior to July 1955,

there were no provisions for such inspection

and certification.

Numerous requests are received from independent processors, trade organizations, and

others for certifications to accompany shipments of inedible animal products to meet the

requirements of certain receiving countries.

The average annual cost for these services is

$15,000 (table 47).

Controls over production and marketing of veterinary biologies

Licensing and Inspection.—The Virus-SerumToxin Act of 1913 prohibits the production and

marketing in interstate commerce of virus,

serums, toxins, and related products except

when produced under a U.S. Veterinary License

issued by the Secretary. Such products must

not be worthless, contaminated, dangerous, or

harmful. Regulatory controls provide for a

system of licensing, inspection, and testing. The

program is one of consumer protection, assuring veterinarians and farmers that the products they buy and use for the diagnosis, prevention, and treatment of animal and poultry

diseases are safe and potent. The average annual cost for these protective services is $540,-

000 (table 47).

Assessment Fee for Control Agency—The

Control Agency for administration of a Marketing Agreement under the provisions of an

Act of Congress regulating handling of antihog-cholera serum and hog-cholera virus consists of 12 members selected by the Secretary

from nominations by the hog cholera industry.

The Secretary has continuing right to disapprove Agency actions or decisions.

Funds collected from assessments against

handlers of serum and virus are used to hire

an Executive Secretary and his secretary, to

maintain an ofiiice in Kansas City, Mo., and for

travel expenses for members of the Control

Agency and the Executive Secretary. The assessments amount to about $32,000 annually

(table 47).

COOPERATIVE PLANT PEST CONTROL

PROGRAMS

Under specific legislation, the U.S. Department of Agriculture cooperates with the States

in certain extensive insect and plant disease

control and regulatory programs. Current programs can be classified into three categories

as follows :

(1) Eradication of incipient infestations of

introduced agricultural pests. The programs in

operation in 1960 were : golden nematode, imported fire ant, khapra beetle, and witchweed.

Infestations of citrus blackfly, Mediterrean

fruit fly, and of Hall scale have been eradicated.

Surveys are conducted each year to confirm

their eradication status.

(2) Prevention of spread of destructive pests

of foreign origin that have become established

in limited areas in this country. Regulatory

programs are being carried on to prevent spread

of the burrowing nematode, European chafer,

gypsy moth, Japanese beetle, Mexican fruit

fly, peach mosaic, phony peach, pink boUworm,

soybean cyst nematode, sweetpotato weevil,

and white-fringed beetle and including the programs mentioned in paragraph (1). Pests confined to limited areas by cooperative control

and regulatory action do not normally cause

the tremendous losses that they would cause if

they were allowed to become distributed over

their potential ecological range.

(3) Suppression of widely distributed insects

and plant diseases that assume outbreak portions periodically, causing extensive agricultural losses that cannot be controlled effectively

by individual effort. These programs include

grasshoppers. Mormon crickets, and stem rust

(barberry eradication). Each year Federal,

State, and private groups spend considerable

amounts to prevent the spread of these insect

pests and plant diseases and to suppress outbreaks

During 1951-60, the average annual expenditure for cooperative regulatory and suppressive

programs was $12,522,116 from Federal

sources and $11,998,599 from non-Federal

sources (table 48).

CONTROLLING EROSION IN 17 WESTERN

STATES

Nearly two-thirds of the acreage needing

vegetation and more than nine-tenths of the

land needing measures to control erosion are

in the 17 Western States. Much of this land

has a low value per acre. However, the benefits

accrue not only to the actively eroding land but

also to neighboring land covered by dunes and

to other neighboring land to which erosion

might extend. The cost of controlling erosion

in this part of the United States is $238,080,000

(table 49).

According to the Great Plains Conservation

Program Act, PL 1021, an estimated 6 million

acres of privately ovmed land m the (jreat

Plains is subject to erosion and the owner is
108 AGRICULTURE HANDBOOK 291, U.S. DEPT. OP AGRICULTURE

TABLE 48.—FEDERAL AND STATE COOPERATIVE PLANT PEST CONTROL AND QUARANTINE PROGRAMS :

Average anniml cost, 1951-60^ _^____^____—

Program 2

Average annual cost

Federal Non-Federal Total

$691,509 $301,333 $992,842

299,458 590,017 889,475

90,782 69,087 159,869

340,454 237,796 578,250

945,716 1,492,199 2,437,915

915,166 1,594,150 2,509,316

87,475 32,944 120,419

76,910 21,098 98,008

2,378,206 1,883,818 4,262,024

518,268 500,291 1,018,559

666,441 663,247 8 1,329,688

895,930 1,372,591 2,268,521

323,485 835,928 3 1,159,413

146,960 137,229 284,189

1,472,841 651,886 2,124,727

283,932 116,151 400,083

227,262 684,914 912,176

56,551 40,000 96,551

722,672 728,404 1,451,076

1,382,098 45,516 1,427,614

12,522,116 11,998,599 24,520,715

Barberry (stem rust control)

Burrowing nematode (5 years)

European chafer (6 years)

Golden nematode

Grasshopper and Mormon cricket

Gypsy moth

Hall scale

Hoja blanca (2 years)

Imported fire ant (3 years)

Japanese beetle

Khapra beetle (6 years)

Mediterranean fruit fly (6 years)

Citrus blackfly and Mexican fruit fly

Peach mosaic and phony peach

Pink boUworm and wild cotton

Soybean cyst nematode (5 years)

Sweetpotato weevil

Tropical termites (1 year)

White-fringed beetle

Witchweed (4 years)

Total

1 All are introduced pests except grasshoppers. Mormon cricket, peach mosaic, and phony peach.

2 For the period of 1951-60, except as indicated.

3 Includes Republic of Mexico.

TABLE 49.—EROSION IN 17 WESTERN STATES :

Estimated average annual cost of control,

1951-60

Kind of

control

Average

annual cost

IfiOO

dollars

Private crop and grazing lands 117,162

Federal grazing lands 36,633

Handling excess irrigation water 84,285

Total 238,080

justified in spending $6.25 per acre for erosion

control. Since 5 years is required to complete

the average contract for this work, the annual

cost to the owner would be $1.25 per acre. But

this is a cost-sharing program; the actual cost

would be $2.50 per acre. On this basis, the

estimated annual cost of controlling erosion

on the 46,850 acres of private crop and grazing

lands in the 50 States, which is about threefourths of the total grazing land, would total

$117,162,000. For federally owned grazing

land, at the estimated cost per acre, the estimate is $36,633,000.

Assuming that the reduction in water handled is a measure of a cost that is preventable

by known methods, and that $1.50 per acrefoot is a reasonable cost-of-handling figure, the

preventable cost of handling excess irrigation

water amounts to $84,285,000 annually.

It should be emphasized that these are estimates of the annual cost of preventing or correcting deterioration. Thus, at the end of 5

years, after the expenditure of about 220 to 300

million dollars, the erosion may be controlled

permanently under reasonable management, or

at least for an indefinite period.

CONTROLLING FIRE, INSECTS, AND

DISEASE IN FORESTS

The United States spends about $84 million

annually to prevent or suppress forest fires

(table 50). About 40 percent of these costs are

TABLE 50.—FIRE, INSECTS, AND DISEASE IN

FORESTS : Average anvxil cost of control, by

source of funds, 1951-60

Source of Type of control

funds Fire Insects Disease Total

Federal

Government __

State and county

governments __

Private agencies

IfiOO

dollars

34,400

82,200

17,400

IfiOO

dollars

3,200

150

100

IfiOO

dollars

3,050

650

50

1,000

dollars

40,650

33,000

17,550

Total 84,000 3,450 3,750 91,200
LOSSES IN AGRICULTURE 109

borne by States and counties, 40 percent by the

Federal Government, and the remainder by

private landowners.

Expenditures for controlling insects in the

forests have averaged about $3,450,000 annually

(table 50). About 90 percent of these funds

have been provided by the Federal Government

and the remainder by States and private agencies.

Expenditures for controlling disease in the

forests have averaged about $3,750,000 annually

(table 50), primarily for control of the whitepine blister rust. Most of these funds have

been provided by the Federal Government, and

the remainder from State and private sources.

CONTROLLING INSECTS AFFECTING CROPS,

MAN, ANIMALS, AND HOUSEHOLDS

Insects that annoy man and transmit human

diseases and that affect his homes, lawns, and

gardens cost considerable to control. The estimated average annual cost of controlling these

insect pests (exclusive of the enforcement of

quarantine and regulatory measures and the

operation of large-scale cooperative control

programs) is about $425,000,000 (table 51).

The cost of these measures may be grouped

under three major categories : (1) insecticidal

control, (2) cultural, mechanical, and sanitation control, and 3) biological control. The

measures are developed by research conducted

by Federal and State agencies and by industry.

The cost of this research is not included in the

estimates.

InsecHcidal control

Availability of new insecticides, changes in

formulations and dosages, and improved methods of application make estimating the cost of

control very difficult. The following procedure

appears to be the most practical.

According to estimates, about 215,000,000

pounds of insecticidal chemicals are used each

year to control insects affecting crops, man,

TABLE 51.—INSECTS AFFECTING CROPS, MAN,

ANIMALS, AND HOUSEHOLDS: Estimated

average annual cost of control, 1951-60

Type of control

Average

annual cost

1,000

dollars

Insecticidal control 420,000

Cultural, mechanical, and

sanitation control 4,000

Biological control 1,000

Total 425,000

animals, and households in the United States

excluding Alaska and Hawaii.i At an average

price of $1.30 per pound, this material would

be valued at approximately $280,000,000. If

the cost of application is assumed to be onehalf the price of the insecticide, about $140-

000,000 should be added. Thus, the estimated

total annual cost of controlling these insects

with insecticides is about $420,000,000.

Cultural, mechankal, and sanitation control

Some of the cultural, mechanical, and sanitation practices used by the grower and the

general public to control insect pests are clean

cultivation, stalk and trash destruction, crop

rotation, hand picking or hand worming, timing

of planting dates, drainage, refuse disposal,

and screening. These practices add appreciably

to the cost of insect control. The amount expended for control has been estimated at

$4,000,000.

Biological control

The expense of utilizing natural enemies such

as insect parasites, predators, and diseases as

a means of combating harmful insects and the

expense of developing crop varieties resistant

to insects is borne chiefly by Federal and State

agencies. Only a few biological control agents

have been available commercially for use by

private individuals. Among these are lady

be-etles for use against mealybugs and certain

scale insects on citrus, the egg parasite Trichogramma against several lepidopterous pests,

and milky disease spore dust to control Japanese beetle grubs. It is estimated that $1,000,-

000 is expended annually in the biological control of insect pests, including the search for

beneficial insects in foreign areas and importation of them into the United States.

CONTROLLING INSECTS IN STORED

PRODUCTS

Damage by stored-product insects is in addition to the direct damage caused by insects to

agricultural commodities after harvest and to

the products derived from these commodities.

Stored-product insects increase the cost of

goods because of the expenditures required for

their prevention and control. These costs affect

farmers, warehousemen, millers, bakers, food

processors, those engaged in transportation

and marketing, and finally, the consumer.

The estimated average annual cost of controlling insects in stored products for the period

1951-60 is $279,302,000 (table 52). But this

is not the total amount required to prevent and

1 HALL, DAVID G. USE OF INSECTICIDES IN THE UNITED

STATES. Ent. Soc. Amer. Bul. 8: 90-92. 1962.
lio AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

TABLE 52.—INSECTS IN STORED PRODUCTS : Estimated average annual cost of control, 1951-60

Commodity

Average

annual

cost

1,000

dollars

Apples 75

Apricots, dried 132

Corn 1,125

Dry corn milling products 1,200

Dry milk (nonfat) 1,162

Figs, dried 283

Macaroni and noodles 1,200

Peaches, dried 45

Peanuts 1,682

Pears, dried 19

Prepared flour and mixes 85,000

Prunes 3,035

Raisins 476

Rice 2,170

Sorghum (grain) 7,635

Tobacco (flue-cured leaf) 1,239

Wheat flour 84,824

Woolens and furs 88,000

Total 279,302

control stored-product insects. Costs considered are primarily for pesticides and the labor

used to apply them. It was not possible to estimate the cost for purchase, maintenance, operation, and deterioration of equipment for applying pesticides or for carrying out sanitation

and housekeeping operations directed primarily

against stored-product insects. No attempt was

made to estimate the additional cost of special

packaging required to protect food products

against insect infestation. The preventive and

control measures used are developed by Federal, State, and industry research, the cost of

which is not included in this estimate. Some

of the cost of inspection, quarantine, and other

regulatory measures is directed toward storedproduct insects such as the khapra beetle, but

the proportionate share has not been determined.

CONTROLLING NEMATODES

Direct expenditure by growers for nematode

control is almost exclusively for soil nematocides and the machinery and labor needed to

apply them. Two methods of applying nematocides are in general use : Field applications and

row applications. By far the largest expenditure is for nematocides applied to soil in field

applications. The average cost is about $30

per acre, including an allowance of $5 per acre

for application. Many growers apply nematocides only to the rows in the field, leaving the

middle untreated. Cost of row applications is

about $15 per acre, including application.

A much smaller but still significant amount

is spent for nematode control on seedbeds and

in nurseries. The materials used usually combine weed seed control and control of soil insects, fungi, and bacteria with nematode control. Costs range up to $10 per 100 square

yards, of which only about one-tenth should be

charged to nematode control.

Exact figures on the production and use of

nematocides are not available. They are extensively used on tobacco in the Southern

United States, on sugarbeets in the West (particularly Utah), and on most pineapple fields

in Hawaii. Use is rapidly increasing on cotton,

peanuts, vegetables, fruit crops, and ornamental

and forest nurseries, especially in the Atlantic

and Gulf Coast States, and in California.

The best estimate is that nematocides were

used on 50,000 acres of tobacco in 1951, on

750,000 acres in 1960, and on an average of

350,000 acres for the 10-year period. Estimates

for other crops are cotton, 20,000 acres ; sugarbeets, 75,000 acres; peanuts, 2,000 acres;

peaches, 4,000 acres ; vegetables, 135,000 acres ;

pineapples, 17,000 acres; and other crops,

100,000 acres. Thus, nematocides were used on

a total of approximately 713,000 acres.

There is no way of knowing what percentage

of this acreage was treated by field applications

($30 per acre) or row applications ($15 per

acre). Assuming an average cost of $22.50 per

acre for nematocide treatment, it is estimated

that the annual cost of nematode control was

about $16,000,000.

CONTROLLING PLANT DISEASES

Common methods of controlling plant diseases include (1) use of disease-resistant varieties; (2) cultural practices such as deep plowing to bury infested crop residues, rotating

crops to avoid a buildup of disease inoculum,

burning infested plant debris, shifting production areas to avoid diseases, removal of alternate hosts, controlled irrigation, use of fertilization and other management practices, and

use of disease-free seed; (3) biological control,

principally for soil diseases such as root rots

and wilts; and (4) use of chemicals for treating seed, disinfesting soil, and as sprays and

dusts applied to the plants to control diseases

and insect vectors of plant diseases.

The total cost of controlling plant diseases is

estimated at $115,800,000 annually for the period 1951-60 (table 53).

Estimates of control costs are difficult and

are made only for chemical control ($100,000,-

000), and for the costs involved in producing

disease-free planting materials ($8,800,000).

Approximately $75,000,000 is paid for fungi-
LOSSES IN AGRICULTURE

111

TABLE 53.—CONTROLLING DISEASES IN THE

PRODUCTION OF CROPS: Estimated average

annvxil cost, 1951-60

Type of

control

Average

annual cost

1,000

dollars

Chemical control:

Fungicides 75,000

Application of fungicides 25,000

Total 100,000

Seed disinfectants 7,000

Production of disease-free planting stock:

Ornamental plants 2,400

Sweetpotatoes 150

Potatoes 6,200

Fruit crops 50

Total 8,800

Grand total 115,800

cides by farmers and commercial pesticide

applicators. It is estimated that 1,000,000 acres

of fruit and nut trees are treated on an average

of four times a year, 1,500,000 acres of vegetables are treated three times, and 1,000,000

acres of potatoes are treated four times. At an

average cost of $2 per acre the total cost of

application of fungicides is approximately

$25,000,000.

The expense of controlling diseases in a particular crop varies considerably. For example,

on potatoes grovm in the arid West, foliage

diseases are of little importance. In Maine, the

8 to 14 applications to control late blight cost

$30 to $50 per acre. Growers of apples in the

Pacific Northwest usually have to spray three

to four times during the season; in the East,

they have to spray 8 to 20 times. Each application costs approximately $8 per acre.

Approximately $7,000,000 is spent for seed

treatment to control diseases (table 53). Most

of the small grain seed treatment is done by

custom treaters. Seedsmen or seed processors

treat most of the corn, cotton, sorghum, peanuts, and vegetable seeds and the cost is included in the selling price.

An estimated $8,800,000 is spent to produce

disease-free planting stock (table 53). For

ornamentals, estimates were made of costs for

indexing and isolating disease-free planting

stock and the increased expenses of propagating chrysanthemums, roses, foliage plants,

carnations, gladiolus, pelargoniums, and lilies.

About 1 million pounds of certified sweetpotato seed stock were grown at an estimated

cost of 15 cents per pound premium cost. Approximately 141,000 acres of certified and

foundation seed potatoes were grown annually

from 1951 to 1960 at an estimated extra cost of

$44 an acre. The additional costs to the grower

or nurseryman of providing virus-free strawberries, grapes, stone fruits, and citrus were

estimated. Costs of administering these programs were not included unless they were

recovered from the producer.

PLANT QUARANTINE AND REGULATORY

MEASURES

The enforcement of quarantines affecting

importation and interstate movement of plants,

plant products, plant pests, soil, and miscellaneous nonagricultural importations found contaminated with pests cost approximately

$4,162,000 annually during the period 1951-60.

This estimate includes (1) Federal appropriations for foreign plant quarantines; (2) contributions by States and offshore possessions,

particularly California, Hawaii, and Puerto

Rico, to the plant quarantine program; and

(3) costs to importers in connection with the

inspection, treatment, cooperage, handhng, and

other incidentals to meet plant quarantine import requirements. The expense of fumigating

or otherwise treating large quantities of imported cotton and cotton products, broomcorn,

fruits, vegetables, used bagging, carriers, and

contaminated nonagricultural cargoes is included in this last group. The fumigation of

ships and cargoes found to carry the khapra

beetle and injurious snails was especially heavy

during the latter part of the 10-year period

covered by this report.

CONTROLLING WEEDS

In addition to the losses caused by weeds

(discussed in chapter 5), the costs of controlling them are a tremendous financial burden.

One of the major objectives of weed control

research is to develop weed control principles

that not only will reduce losses in yield and

quality caused by weeds but also will reduce

the cost of weed control. Lower costs of controlling weeds will provide a better profit margin for farmers, improve the competitive position of American agriculture, and benefit the

consumer by reducing the prices of food, feed,

and fiber.

Methods of controlling weeds include hand

pulling, hand hoeing, cultivating, disking, plowing, harrowing, rotary hoeing, mowing, crop

rotation, fallowing, bulldozing, chaining, draglining, herbicide application, mulching, and

use of biological control agents such as insects,

snails, geese, fungi, and various animals. The

method adopted and used by farmers depends

largely on its cost and relative efficiency in
112 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

TABLE 54.—WEEDS '.Estimated average annual cost of control in various crov and noncrop areas

by cultural and chemical methods, 1951-60

Crop and

noncrop areas

Average annual cost

Cultural

methods

Chemical

methods i Total

1,000 dollars

1,745,977

307,000

348,308

1,000 dollars

92,023

3,050

16,692

lyOOO dollars

2 1,876,000

310,050

365,000

55,637

Field and seed crops

Horticultural crops

Hay crops, pastures, and

rangelands

Aquatic and noncrop

areas

Total 2,401,285 111,765 2,606,687

1 Data are for 1959 only.

2 Includes $21,000,000 for costs of cultural andchemical control of weeds in flax and $17,000,000 for

these costs in sugarcane.

controlling weeds in a particular crop or situation. The estimated average annual cost of

cultural and chemical control of weeds for

various crop groups is given in table 54, and

for individual crops in tables 55, 56, and 57.

Estimates are based on experimental data and

the judgment of plant scientists and other

scientists concerned with weed control and

other farm operations. Because adequate data

were not available, estimates of the cost of weed

control in some crops are not given. Estimates

of costs of cultural and chemical control of

weeds in aquatic and noncrop areas, chargeable

to agriculture, are presented in table 58.

¥ield crops

The annual weed control operation in field

crops is far greater than generally realized.

Approximately 120 million acres of intertilled

row crops receive intensive weed control practices each year. More than 200,000,000 acres

of drilled field crops receive moderate weed control practices. The intertilled row crops usually

receive from two to five tillage treatments for

seedbed preparation and from one to as many

as seven cultivations in a single growing season. More than half of the total tillage operations in agronomic crops are practiced for the

sole purpose of controlling weeds, and no other

advantage can be attributed to these practices.

Weeds in agronomic crops are controlled by

cultural, ecological, mechanical, chemical, and

combination methods. Nonchemical methods

were used on 87 percent of the total field crops

planted in 1959.

Special equipment for controlling weeds includes tillage implements of all kinds, mowers,

sprayers, and burners. Also, every grain elevator and commercial seed processor is

equipped with expensive machinery for removing weed seed from crop seed.

A survey conducted by the U.S. Department

of Agriculture in 1959 showed that farmers

are rapidly accepting the use of herbicides for

weed control in field crops. In that year field

crops, not including pastures and rangelands,

were grown and harvested on approximately

320,000,000 acres. Herbicides were used to control weeds on more than 45,000,000 acres, and

nonchemical methods were used to control

weeds on the remaining acreage. In 1959 about

13 percent of the total harvested acreage of

field crops was treated with herbicides for weed

control. Since 1959 the acreage has expanded

rapidly.

There is little doubt that weed control is practiced on a wider scale than any other pest control operation in field crop production. The

costs of weed control are high and represent

a large proportion of the total cost of controlling pests. If control of weeds is neglected or

ineffective, yields will be reduced accordingly.

As a general rule, no other single operation

under the control of the farmer may influence

final yields and quality of crops so greatly.

The cost of weed control in field crops includes part of the cost of seedbed preparation,

tillage, and cultivations necessary to control

weeds, and all the cost of preemergence, postemergence, layby, and preharvest herbicidal

treatments. Weeds are controlled in many crops

by hand hoeing, hand pulling, flooding, mowing,

burning, flaming, and mulching.

The cost of controlling weeds in field crops

ranged from $3.15 per acre for oats to $33 per

acre for sugarbeets. These costs ranged from

8 percent of the total per acre value of sugarcane to as much as 39 percent of the value of

alfalfa grown for seed. The cost of controlling

weeds in 39 major field crops averaged 15 percent of the total value of the crops produced
LOSSES IN AGRICULTURE

113

and amounted to $1,876,000,000 per year

(table 54). The loss in value to certain field

crops is given in table 55.

Corn.—The average cost of weed control in

corn is about $6.65 per acre, or more than

$534,000,000 each year. This is about 12 percent of the value of the crop. Thorough seedbed

preparation, rotary hoeing, and shallow cultivations, supplemented by some hand hoeing and

hand pulling, are the most important cultural

practices of weed control. However, more than

20,000,000 acres of the crop are being treated

with herbicides each year at a cost of approximately $37,980,000 (table 55). The cost of

preemergence herbicide treatments for weed

control in corn averaged $3.68 per acre and

the cost of postemergence treatments $1.67.

Farmers applied herbicides on 82 percent of

the total treated acreage with their own equipment; custom operators treated the remaining

18 percent.

The use of herbicides to control weeds in

corn is expanding rapidly in an effort to reduce

the cost of weed control and to increase the

efficiency of controlling weeds in corn by eliminating the need for repeated cultivations and

hand hoeing and to permit the use of minimum

tillage practices.

TABLE 55.—FIELD CROPS: Estimated average

annual cost of controlling weeds by

cultural and chemical methods, 1951-60

Average annual cost

Crop Cultural Chemical

methods methods i Total

IfiOO IfiOO IflOO

dollars dollars dollars

Com 496,020 37,980 534,000

Cotton 437,372 4,628 442,000

Beans, dry 33,000 33,000

Sorghum, grain 53,489 6,511 60,000

Rice 23,112 888 24,000

Small grains:

Barley 76,905 3,095 80,000

Oats 130,000 4,000 134,000

Wheat 293,000 30,000 323,000

Alfalfa (seeds) 16,225 775 17,000

Other grass and

legume seed crops _ 39,907 1,093 41,000

Soybeans 99,687 2,313 102,000

Flax 21,000

Peanuts 19,884 116 20,000

Sugarbeets 27,376 624 28,000

Sugarcane 17,000

Total 1,745,977 92,023 1,876,000

1 Calculated from average costs incurred by farmers

and other land owners in States reporting. Alaska,

California, Delaware, Hawaii, New Jersey, New York,

Ohio, Oklahoma, and Washington not included. Costs

based on data for one year, 1959.

Cotton.—The cost of controlling weeds in

>tton with conventional methods averaged an

proximately $22 per acre. The cost represente

about 19 percent of the total value of the cotton

crop and amounts to $442,000,000 each year

The use of herbicides to control weeds in cotton is expanding at a rapid rate. In 1959 it

IS estimated that about 1,500,000 acres'of

cotton were treated with herbicides to control

weeds, at a total cost of approximately $4,628 -

000 (table 55). ^ ^ ^ 0,

The cost of preemergence appHcations averaged $3.22 per acre, whereas postemergence

herbicide treatments averaged $2.69 per acre.

Farmers treated 92 percent of the total acreage

with their own equipment; custom operators

treated approximately 8 percent.

Conventional methods of weed control such

as tillage, cultivation, and hand hoeing required

an average of 27 man-hours per acre. By using

herbicides to supplement cultural practices, the

cost of weed control has been reduced from $22

to about $10 per acre and the labor from 27

to approximately 10 man-hours per acre.

Sorghum, Grain,—The average annual cost

of weed control in grain sorghum is approximately $5 per acre, or more than $60,000,000

(table 55). This is about 17 percent of the

value of the crop.

In 1959 more than 2,000,000 acres of grain

sorghum were treated with herbicides as postemergence sprays. Improved preemergence

herbicides have been developed recently, and

their use is expanding. The total cost of treating 2,000,000 acres of grain sorghum for weed

control in 1959 amounted to $6,511,000 (table

55). The average cost of preemergence treatments was $6 per acre, and postemergence

treatments averaged $3.10 per acre. The cost

of herbicide treatments for weed control in

grain sorghum varied considerably. Postemergence treatments ranged from as low as

40 cents per acre to as much as $4.

Rice.—The average cost of controlling weeds

in rice was $13 per acre, amounting to about

$24,000,000 per year (table 55). This is about

9 percent of the total farm value of the rice

crop.

Recent surveys indicate that practically the

entire rice crop is treated with postemergence

sprays of the phenoxy herbicides or 3^4ldichloropropionanilide (propanil). The average

cost of the phenoxy herbicides for the control

of broadleaf weeds in rice amounted to about

$1.77 per acre.

The use of herbicides represents only a fraction of the total cost of controlling weeds m

the rice crop. Land leveling, levy construction,

seedbed preparation, maintenance of excessive

water depths, timing of fertilizer applications
114 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

to avoid stimulating weeds, and other factors

add greatly to the cost of controlling weeds in

rice. Herbicides are used widely to improve

the efficiency of weed control and to reduce

costs.

STuall Grains (Wheat, Oats, and Barley),—

The average cost per acre for weed control in

wheat is $5; oats, $3.15; and barley, $5.75.

These costs amounted to 15 percent of the value

of wheat; 15 percent of oats; and 21 percent

of the farm value of barley. Farmers spend

$80,000,000 per year to control weeds in barley ;

$134,000,000 in oats; and $323,000,000 in

wheat (table 55). In 1959, the phenoxy compounds were used to control weeds in 21 million acres of these crops at a cost of more than

$37,095,000 (table 55). Practically no herbicides are used as preemergence treatments to

control weeds in small grains, so most of the

acreage was treated postemergence with the

phenoxy herbicides.

The average cost of postemergence herbicide

treatments for controlling weeds in small grains

was $1.79 per acre. Farmers purchased the

herbicides and used their own equipment on

75 percent of the acreage treated; custom operators sprayed 25 percent.

The use of herbicides is essential for efficient

weed control in small grains. Cultural practices for controlling weeds in small grains include thorough seedbed preparation and the

choice of adapted varieties, properly fertilized

and planted at optimum dates to insure vigorous stands of rapidly growing plants. Once

the grain crops are planted, there are no other

cultural practices of weed control other than

hand pulling. The use of herbicides for weed

control in small grains is expanding rapidly,

and this trend is expected to continue.

Forage Grass and Legume Seed Crops,—The

average cost of weed control in forage-seed

crops ranged from $5 per acre for lupines to

about $18 per acre for alfalfa. This is 39 percent of the value of the alfalfa seed crop.

Farmers spend annually more than $17,000,000

for weed control in alfalfa and approximately

$41,000,000 for weed control in other grass

and legume crops grown for seed production

(table 55). Cultural practices alone have

proved only partially satisfactory. Preemergence and postemergence herbicide treatments

to control weeds in these crops are expanding

rapidly. Dodder is especially serious in alfalfa

seed production, and the cost of controlling

this parasite is considerable. No combination

of cultural practices has controlled dodder, but

supplementing cultural practices with chemicals

is proving satisfactory.

Soybeans.—The average annual cost of weed

control in soybeans is $5.50 per acre, which is

about 11 percent of the total value of the crop.

Each year farmers spend approximately $102,-

000,000 (table 55) to control weeds in soybeans.

Methods of controlling weeds in soybeans include thorough seedbed preparation and the

establishment of excellent stands of vigorous

varieties by planting at optimum dates to give

rapid, early season growth, followed by rotary

hoeing, shallow cultivation, some spot hand

hoeing and hand pulling. The use of herbicides

for emergence control of weeds in soybeans is

expected to increase rapidly as improved herbicides are introduced.

Flax.—The average annual cost of weed

control in flax is $4.50 per acre, or 19 percent

of the value of the crop. Farmers spend approximately $21,000,000 (table 55) each year

to control weeds in flax. Cultural methods of

weed control, including thorough seedbed preparation, hand pulling, and other methods, have

proved relatively inefficient in preventing serious losses from weed competition in this crop.

The use of herbicides for controlling weeds

in flax is expanding rapidly. For example, in

Minnesota in 1961, more than 400,000 acres

of flax were treated with herbicides for weed

control. This was approximately 90 percent

of the total acreage of flax in the State. Use

of herbicides in flax in all production areas is

expected to expand.

Peanuts.—The average annual cost of weed

control in peanuts is $13 per acre, or 12 percent of the value of the crop. Farmers spend

approximately $20,000,000 (table 55) annually

to control weeds in the crop. Approximately

300,000 acres of peanuts are treated each year

with preemergence herbicides to control weeds,

at an average cost of about $4.36 per acre.

The acreage of peanuts treated with herbicides as postemergence sprays for the control

of weeds is expanding. The cost of postemergence treatments averages about $3 per

acre. Cultural methods of weed control consist

of thorough seedbed preparation, rotary hoeing, the use of finger weeders, frequent shallow

cultivation, plus hand hoeing and hand pulling.

Farmers are expanding the use of herbicides

in order to reduce hand hoeing and other weed

control costs in peanut production.

Sugarbeets.—The average cost of weed control in sugarbeets was $33 per acre, or 18 percent of the value of the crop. Farmers spend approximately $28,000,000 (table 55) each year

to control weeds in sugarbeets. Cultural methods of weed control include thorough seedbed

preparation, blocking, thinning, hand hoeing,

hand pulling, and frequent cultivations.

The introduction of monogerm varieties of

sugarbeets greatly increases the need for chemi-
LOSSES IN AGRICULTURE

115

cal methods of controlling weeds. If satisfactory chemical methods can be developed to

control weeds, monogerm varieties will permit

planting to a stand and eliminate the need for

blocking and thinning.

The average cost of preemergence treatments

is approximately $5.24 per acre; postemergence

treatments average about $4.63 per acre. In

1959, $624,000 was invested in herbicides and

their application for the control of weeds in

the crop (table 55) and their use is expected

to expand rapidly as more effective herbicides

are developed.

Sugarcane,—The average cost of controlling

weeds in sugarcane is approximately $22 per

acre, or 8 percent of the value of the crop.

Farmers spend approximately $17,000,000

(table 55) each year to control weeds in

sugarcane. Methods of controlling weeds in

sugarcane include fallow plowing, thorough

seedbed preparation, frequent cultivations in

some areas, and hand hoeing.

The use of herbicides to control weeds in

sugarcane is expanding rapidly. The entire

sugarcane crop on the mainland and in Hawaii

receives phenoxy or other herbicides to control

broadleaf weeds and grasses. For example, in

Hawaii about 100 thousand acres of sugarcane

are treated with herbicides four to five times

each year—an accumulative half a million

acres. The cost of chemical weed control in

sugarcane in Hawaii alone amounts to about

$7,000,000 annually.

^ Cultural practices alone have not been efficient in controlling johnsongrass and other annual and perennial broadleaf weeds and annual

grasses in sugarcane. The use of herbicides is

expanding rapidly as supplemental techniques

for the control of weeds in combination with

cultural practices.

Horticultural crops

Horticultural crop plantings total about

8,000,000 acres. Until very recently, repeated

hand weedings and intensive cultivation with

a variety of implements were necessary to control weeds in many of these crops. Effective

chemical methods of controlling weeds have

been developed for a number of these crops but

grower acceptance varies from poor to excellent depending on the crop, location, cultural

practices, and economic stresses. In most instances, herbicides are used in combination

with mechanical cultivation and hand weeding.

The net result of herbicide use is therefore a

reduction in mechanical and hand weeding and

not an elimination of these practices.

Methods of controlling weeds in horticultural

crops include : (1) hand pulling; (2) hand hoeing; (3) mechanical cultivation; (4) disking;

5 plowing; 6) harrowing; (7) mowing-

(8) crop rotation; (9) fallowing; (lorsoii

fumigation; (11) herbicide application and

(12) mulching.

Because of the many crops involved and the

many methods and combinations of methods

that are used in horticultural crops, it is difficult to accurately assess the extent of use of

the various methods and their cost. Limited

data have been reported and these combined

with knowledgeable estimates constitute valuable information for charting the trends in

weed control costs. The loss in value to horticultural crops as a group is $310,050,000

(table 56).

Vegetable Crops,—Many vegetable crops are

planted at high seeding rates and the plants

are very small at emergence and grow slowly

for a period of time. Weeds that emerge between the crop plants in the row are difficult

to remove by mechanical cultivation and much

hand labor is necessary where effective herbicides are not available. Reports indicate a

very limited use of herbicides in these crops in

1959 suggesting that mechanical and handweeding methods were generally used.

Approximately 4,900,000 acres of vegetable

crops were grown commercially in 1959. The

cost of weed control by all methods and combinations of methods is estimated at $70 per

acre for 2,800,000 acres of general vegetable

crops including melons; $14 per acre for

1,300,000 acres of potatoes; $20 per acre for

634,000 acres of sweet corn; and $70 per acre

for 113,000 acres of onions. This amounts to

a total cost for control of about $224,418,000

for all vegetables (table 56). This amounts to

an average cost of about $45 per acre for

vegetables.

TABLE 56.—HORTICULTURAL CROPS: Estimated

annual average cost of controlling weeds by

cultural and chemical methods, 1951-60

Commodity groups

and crops

Average annual cost

Cultural

methods

Chemical

methods i Total

Vegetable crops

Tree fruits, nuts,

vineyards

Strawberries and

cranberries —

Ornamentals

Lawns

and

IfiOO

dollars

223,000

40,000

11,000

33,000

IfiOO

dollars

1,418

43

55

45

1,489

IfiOO

dollars

224,418

40,043

11,055

33,045

1,489

Total 307,000 3,050 310,050

1 Based on data for 1959.
116 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

Tree Fruit and Nut Crops and Vineijards,—

Many annual and perennial weeds infest orchard and vineyard plantings. Methods of

control include the use of mechanical tillage,

organic chemical herbicidal oils, mowing, and

various combinations of these methods. The

method to use depends on topography, cultural

practices, and climate. Many citrus growers

are using herbicidal oils and organic chemical

herbicides for controlling practically all weeds

in these crops. Herbicides are used to a lesser

extent in other orchard and vineyard plantings. The methods and cost of weed control

used in orchard and vineyard plantings, therefore, vary widely.

Approximately 2,800,000 acres of tree fruit

and nut crops and grapes were grown commercially in 1959. The cost of weed control by all

methods is estimated at $35 per acre for about

779,000 acres of citrus; $5 per acre for 1,700,-

000 acres of deciduous tree fruits; $10 per acre

for 248,000 acres of tree nut crops; and $20

per acre for 89,000 acres of miscellaneous

plantings including grapes. The total annual

cost of control is about $40,043,000 (table 56).

This is an estimated average annual cost of

about $14 per acre for all tree fruit and nut

crops and grapes.

Strawberries and Cranberries,—Intensive

weed control practices are necessary in strawberries and cranberries because they are perennials. Winter and summer annual weeds must

be controlled and many perennial broadleaf

weeds and weed grasses are critical problems.

The matted bed culture of strawberries limits

mechanical cultivation to the first few weeks

after establishment of new plantings to permit

runner plant rooting. Thereafter, hand weeding or herbicides, or a combination of these

weed control methods, are used. Use of herbicides does not eliminate—^but does reduce—

hand weeding or cultivation.

The matted growth of cranberries prevents

mechanical cultivation of any kind after establishment. Mowing, flooding, and herbicides are

used in combination to control weeds.

Approximately 96,000 acres of strawberries

and 21,000 acres of cranberries were grown

commercially in 1959. The cost of weed control

by all methods and combinations of methods is

estimated at $105 per acre for strawberries and

$40 per acre for cranberries for a total annual

cost of about $11,055,000 for these crops (table

56).

Ornamentals.—Weed control in commercial

nurseries involves propagating beds, cold

frames, liner plantings, and long-term field

plantings. Propagating beds and cold frames

are often treated with soil fumigants to control weeds. Liner plantings must be hand

weeded at frequent intervals, and general field

plantings must be cultivated frequently with

supplemental hand weeding unless herbicides

can be used. Selective herbicides are used on

a number of these crops in combination with

hand weeding and mechanical weeding methods.

Preemergence herbicide treatments are being

used to control some weeds in bulb crops. They

are supplemented by hand weeding and mechanical cultivation. Other miscellaneous ornamental crop plantings including cut flowers

and flower seed crops are weeded by hand and

mechanical methods.

Approximately 191,000 acres of ornamental

and nursery crops were grown commercially in

1959. The cost of weed control by all methods

and combinations of methods is estimated at

$200 per acre for about 139,000 acres of nursery

crops and $100 per acre for about 53,000 acres

of bulb and miscellaneous ornamental crops for

a total cost of about $33,045,000 for all of these

crops (table 56). The average cost of weed

control for ornamentals, based on these estimates, is about $173 per acre.

Hay crops, pastures, and rartgelands

Cost of spraying for weed control on pastures

in 1959 in the 33 States that provided estimates

was about $2.40 per acre, or a total cost in those

States of $5,789,000. If these figures are projected to include the eight additional States

that did not give estimates but that have appreciable pasture acreages, the total cost of

spraying for weed control in pastures would

be nearly $7,200,000 (table 57) for the United

States.

Estimates of costs of chemical controlling

of brush and weeds on rangelands were furnished in 1959 by 13 of the 19 States having

extensive rangeland acreage. The average cost

per acre was about $3, or a total cost in those

States of $6,174,000. If the acreages sprayed

in six other States were included, the total costs

of spraying would be about $7,800,000 (table

57).

In 1959, States gave estimates of the costs of

spraying for weed control in hay crops. The

TABLE 57.—HAY CROPS, PASTURES, AND RANGELANDS: Estimated cost of controlling

weeds by chemical methods, 1959

Commodity Cost

IfiOO

dollars

Hay crops 1,692

Pastures 7,200

Rangelands 7,800

Total 16,692
LOSSES IN AGRICULTURE

117

cost per acre was estimated to be about $6.25,

or a total cost of $1,692,000 (table 57) for the

acreage treated.

Thus, the total estimated cost of weed control

on pastures and rangelands by use of herbicides

in the United States was about $16,692,000 in

1959 (table 57).

Total cost of controlling weeds and brush in

pasture and forage crops in the United States is

not available because the extent of use for some

of the methods of control is not known. The

estimated annual cost of mowing, herbicides,

grubbing, root plowing, chaining, controlled

burning, clearing, cutting and burning, and

bulldozing is $365,000,000 (table 54).

Hand grubl3ing of small brush plants such as

mesquite, cactus, and other species is still practiced on a considerable acreage. The cost per

acre varies with the number of plants per acre

and their size. In one operation in New Mexico,

costs were reported as 67 cents per acre for

grubbing 25 plants per acre of mesquite having

a crown spread of 36 inches or less. This left

16 larger mesquite plants per acre to control by

more expensive methods. Therefore, the cost

of removing all these trees would be more than

double the 67 cents per acre.

''Root plowing'' for control of brush is used

extensively in the Southwest. Costs per acre in

Texas were reported as $10 to $17 per acre.

Cost of plowing sagebrush in the Western

States is reported to vary from $3 to $4 per

acre.

Chaining is also used for partial control of

brush. Even aged juniper and other woody

plants may be pulled down where terrain and

freedom from obstructions permit. Cost of

chaining varies with size of trees and terrain.

A study in Texas gave costs of $2 to $3 per acre

with $10 as the cost if the uprooted brush was

raked into windrows. In Texas chaining did

not kill much brush but gave enough control

that a fair increase in grass production resulted.

Cost of sagebrush beating in the Western

States is about $4 per acre, but data are not

available on the acreage of rangeland treated

in this way.

Cost of controlled burning used for control

of chaparral, sagebrush, and some other types

of brush vary greatly with area to be burned,

size of standby crew required for safety,

amount of preparation necessary for burning,

and other variables. In California costs of

burning ranged from $3.60 per acre for areas

of about 50 acres to 40 cents for large areas up

to 5,000 acres. Cost of burning sagebrush in

Oregon was reported to be 45 cents per acre.

Clearing brush by cutting and burning the

cut brush in Missouri cost $37 per acre. When

the stumps were also sprayed with 2,4,5,-T in

diesel fuel to prevent resprouting, the total cost

was $43 per acre. Where the trees were allowed

to remain standing and the base of the trunks

sprayed with 2,4,5-T in diesel oil for control,

the cost was $19 per acre. Use of heavy bulldozers for clearing and piling brush costs from

$10 to $50 depending on size and density of the

woody plant cover.

Aquatic and noncrop areas

Costs of weed control usually are considerably higher per unit of area in aquatic and noncrop areas than in cultivated crops and in

pastures and rangelands. However, in most

aquatic and noncrop areas the costs of weed

control are much less than the losses caused by

weeds in untreated areas. The estimated annual loss due to weeds in aquatic and noncrop

areas is $55,637,000 (table 58).

Western Irrigation Systems,—Based on a

survey conducted in 1957, the annual total cost

of weed control for aquatic sites and ditchbanks in irrigation systems in the 17 Western

States is approximately $8,113,000 (table 58).

The cost per acre or per mile varies widely—

from less than $10 to more than $400, depending

on the chemical or mechanical method used.

The average cost of weed control was $56.20

per mile of canal in 1957. The estimated annual

saving through weed control was $15,860,000,

or a net saving of approximately $7,747,000.

In this instance, the ratio of losses caused by

weeds to cost of weed control was nearly 2:1.

TABLE 58.—AQUATIC AND NONCROP AREAS:

Estimated annvxil cost of controlling weeds

by cultural and chemical methods

Estimated

Location annual

cost

IfiOO

dollars

Aquatic sites:

Irrigation systems, 17 Western

States l^%l

Farm ponds and reservoirs o,^\fo

Total 7,088

Ditchbanks:

Irrigation systems, 17 Western

States D,oZi

Drainage ditches, 31 Eastern States ___12^349_

Total ^^^^"^^

Noncrop areas: i Q /ii p; Highway rights-of-way o n7á

Railroad rights-of-way 2'l/¿^

Fencelines ^^^^^

Total 29,679

Grand total ^^^^^^
118 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

Eastern Drainage Ditches and Water Control Canals.—Costs of weed and brush control

in drainage and water control canals of the 31

Eastern States ($12,349,000, table 58) are considerably higher than on irrigation systems of

the West, but the proportion of canals and

ditchbanks treated in Eastern States is considerably less. The estimated costs of control

were $65 per mile of ditch or canal treated.

No reliable estimates are available on the relative amount of weed losses prevented by weed

control on drainage ditches and water control

canals in Eastern States.

Farm Ponds and Reservoirs.—The development of effective, economical, and safe methods

of controlling weeds in farm ponds and irrigation reservoirs has not progressed as far as

the development of improved methods for weed

control in canals and ditches. While chemical

control of algae in ponds and reservoirs is a

rather common practice, new methods of controlling submersed aquatic weeds have had only

limited use. As a result the annual cost of weed

control in ponds and reservoirs is only about

$5,496,000 (table 58), which is about 20 percent as much as the estimated annual losses

caused by weeds in ponds and reservoirs (table

45 of chapter 11).

Highway Rights-of-Way.—Costs of weed

control on 3,000,000 miles of Federal, State,

county, and township roads through rural areas

total $97,074,000 annually. It is estimated

that 80 percent of this cost is chargeable to

highway safety and beautification ; and 20 percent, or $19,415,000 (table 58), is chargeable

to the protection of adjacent farms from weed

infestation and other losses caused by weeds.

Railroad Rights-of-Way.—Actual costs of

treating noxious weeds on railroad rights-ofway to protect adjacent farmland in 1961 were

obtained from Idaho, Kansas, and Minnesota.

By extrapolation of these figures, the total annual cost of controlling weeds on railroad

rights-of-way was estimated at $2,074,000

(table 58). This represents 6.91 percent of the

$30,000,000 total annual expenditure for vegetation control on railroads in the United

States.

Fencelines.—Definite figures on the total

cost of weed control in fencelines are not available. Average cost per acre was $8.83 for foliage sprays and $95.45 for soil sterilant treatments. On the basis of estimates from State

weed supervisors and Extension weed specialists in different regions, the total annual

cost of weed control in fencelines in the United

States is approximately $8,190,000 (table 58).
Chapter 13.-Summary

A summary of the estimated annual losses

to agricultural commodities from various hazards, the costs of controlling these losses, and

the cost of various inspection and quarantine

programs is given in table 59.

Losses during production to crops, due to

diseases, air pollutants, nematodes, insects,

weeds, fire, inefficient farm operations, and

inadequate harvesting operations amount to

$11,230,353,000. Loss to the honeybee industry

due to insect pests is estimated at $500,000

annually. Fire, insects, diseases, and other

causes reduce the value of forest trees and

forest nurseries by $253,920,000 annually. The

average losses to livestock, poultry, and their

products during production amount to

$2,787,414,000 each year. Therefore, the average annual loss to crops, forest trees and forest

nurseries, and livestock, poultry and their products during production is estimated at

$14,272,187,000 (table 59).

After the crops and livestock are produced,

they are subject to losses in storage, marketing,

and processing. During storage of crops, insects and other causes reduce the value by

$1,042,063,000. Losses during transit and unloading of fruits and vegetables are estimated

at $121,793,000 and the losses to these two commodities in retail stores is estimated at

?67,841,000 annually. Thus, the losses for

fruits and vegetables during various marketing

stages are $189,634,000. The losses of animal

and livestock products because of condemnations during inspection amount to $60,302,000

annually. Average annual losses to field, fruit,

and vegetable crops during processing is estimated at $85,131,000. During the marketing

and processing of poultry and poultry products

the estimated annual loss is $77,644,000.

Values for losses in forest products are estimated at $825,000,000 annually. The total loss

during storage, marketing, and processing of

agricultural commodities and forest products is

estimated at $2,279,774,000.

Soil-deterioration losses and flood damage on

croplands, ranges, and watersheds amount to

an estimated $2,956,329,000 annually. Water

losses through irrigation, évapotranspiration,

and aquatic weeds (including some loss due to

weeds on noncropped areas) are estimated at

$918,730,000.

The losses resulting from weeds in fencelines and damage to canals, structures, and

farms are estimated at $2,760,000.

The total cost of controlling losses in agricultural commodities and forests and forest

nurseries, and the cost of the State and Federal

inspection and quarantine programs amounts

$3,849,688,000 annually.

119
120 AGRICULTURE HANDBOOK 291, U.S. DEPT. OF AGRICULTURE

TABLE 59.—SUMMARY: Estimated average a^inual losses to agricultural commodities from various

hazards, and cost of controlling these losses and of inspection and quarantine programs, 1951-60

Kind of loss and control programs

Loss in

value

CROPS, PASTURE AND RANGE PLANTS, AND LIVESTOCK LOSSES:

During production :

Diseases of crops and pasture and range plants

Loss to crops from air pollutants ,. Nematode damage ^ t rn^^

Injurious insects ^íl'^

Loss to honeybee industry by insect pests

Weeds in crops and pasture and range plants

Fire and inefficient farm operations

Forest trees and nurseries

Losses during harvesting of crops

Livestock, poultry, and their products:

Infectious and noninfectious diseases and nutritional

disorders

Internal parasites

Insect pests

1,000 dollars

3,261,114

325,000

372,335

3,312,906

500

2,459,630

510,887

253,920

998,481

1,569,358

340,206

877,850

Total -l4'^l{ m 14,272,187

After production :

During storage (due to insects and other than insects)

During marketing of fruits and vegetables and losses in

retail stores

Meat and poultry condemnations

During processing of field, fruit, and vegetable crops

Marketing and processing losses in poultry and poultry

products

Forest products

Total

SOIL AND WATER LOSSES :

Losses to erosion and water

Water losses due to—

Irrigation

Evaportranspiration

Aquatic weeds

Total

Losses caused by weeds in fencelines and damage to canals,

structures, and farms

1,042,063

189,634

60,302

85,131

77,644

825,000

2,279,774

2,956,329

665,000

204,000

CONTROL PROGRAMS:

Animal-disease eradication programs

Animal inspection and quarantine programs

Cooperative plant pest control programs

Plant quarantine and regulatory programs __

Total

Cost of

control

1,000 dollars

115,800

"YêfiOO

1 425,000

275~5T,Ô50

""9T,20Ô

(1)

279,302

2 238,080

3 49,730 4 55,637

3,875,059

2,760

47,578

1,358

24,521

4,162

3,849,688

1 Includes cost of controlling insects affecting crops,

man, animals, and households.

2 Estimated average annual cost of controlling erosion in 17 Western States, 1951-60.

3 The value of irrigation water used in computing the

loss was $2.09 per acre-foot instead of the value of $20

per acre-foot given by Wollman and others (ch. 12,

footnote 11). On this basis, the estimated loss would be

$39,332,700 instead of $4,110,000 as given in table 43.

4 Includes cost of controlling weeds in fencelines,

canals, structures, and farms.

"it U. S. GOVERNMENT PRINTING OFFICE: 1965 773804