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SWEET CHERRIES:

Production, Marketing, and Processing

Agriculture Handbook No. 442

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Agricultural Research Service

UNITED STATES DEPARTMENT OF AGRICULTURE
PRECAUTION

Pesticides used improperly can be injurious to man, animals, and plants. Follow the directions and

need all precautions on the labels.

Store pesticides in original containers under lock and key—out of the reach of children and

animals—and away from food and feed.

Apply pesticides so that they do not endanger humans, livestock, crops, beneficial insects, fish, and

wildlife. Do not apply pesticides when there is danger of drift, when honey bees or other' pollinating insects are visiting plants, or in ways that may contaminate water or leave illegal residues.

Avoid prolonged inhalation of pesticide sprays or dusts; wear protective clothing and equipment

if specified on the container.

If your hands become contaminated with a pesticide, do not eat or drink until you have washed

In case a pesticide is swallowed or gets in the eyes, follow the first aid treatment given on the

label, and get prompt medical attention. If a pesticide is spilled on your skin or clothing, remove

clothing immediately and wash skin thoroughly.

Do not clean spray equipment or dump excess spray material near ponds, streams, or wells Because It is difficult to remove all traces of herbicides from equipment, do not use the same equipment for insecticides or fungicides that you use for herbicides.

Dispose of empty pesticide containers promptly. Have them buried at a sanitary land-fill dump

or crush and bury them in a level, isolated place.

NOTE : Some States have restrictions on the use of certain pesticides. Check your State and local

regulations. Also, because registrations of pesticides are under constant review by the Federal

Environmental Protection Agency, consult your county agricultural agent or State Extension specialist to be sure the intended use is still registered.

This handbook updates information on cherry production that formerly appeared in Farmers'

Bulletm 2185, "Growing Cherries East of the Rocky Mountains," and its predecessor. Farmers'

Bulletin 776, of the same title.

fPKOTECïd
SWEET CHERRIES:

Production, Marketing, and Processing

By H. W. FoGLE, J. C. SNYDER, H. BAKER, H. R. CAMERON,

L. C. CocHRAN, H. A. SCHOMER, and H. Y. YANG

Agricultitre Handbook No. 442

Agricultural Research Service

UNITED STATES DEPARTMENT OF AGRICULTURE

Washington, D.C. Issued December 1973

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

Washington, D.C. 20402—Price $1.40

Stock Number 0100-02730
CONTENTS

Page

Introduction 1

Botanical classification 2

Areas of adaptation _ 3

Importance of crop _ 3

Responses to climate _ 5

Winter- and frost- hardiness _ 5

Rain cracking of fruit _ 5

Fruit doubles 7

Soil requirements . 7

Cultivars (Varieties) _ 8

Main cultivars _ „ ^ _ 8

Special-purpose cultivars _ 11

New and promising cultivars - - _ _ _ 13

Pollination requirements _ 18

Propagation 19

Rootstocks 20

Interstocks ^ 21

Topworking 22

Orchard planting _ 22

Site 22

Selection of nursery stock _ 22

Soil preparation 23

Time of planting _ 24

Tree spacing 24

Transplanting _^ 25

Tree heading and training _ _ 25

Care of young trees 26

Orchard management _ _ 26

Cultivation _ 26

Fertilizers 26

Irrigation 28

Cover crops and intercrops _ 28

Weed control 29

Pruning and thinning 31

Pruning 31

Thinning fruit ^ 35

Protection against birds _ „ 36

Insects and mites 37

Cherry fruit flies 38

Black cherry aphid ^ ^ ^ 40

Mites _ _ 41

Pear slug ^ 44

Plum curculio 45

San Jose scale 46

Shot-hole borer 46

Lepidopterous larvae 47

Page

Fungal and bacterial diseases 49

Brown rot 50

Armillaria root rot 52

Verticillium wilt „ _ _ 53

Collar rot or crown rot . _ „ 53

Cherry leaf spot _ _ 53

Coryneum blight 54

Witch's broom 54

Black knot _ 54

Powdery mildew 55

Perennial canker 55

Bacterial canker 55

Crown gall 57

Virus and viruslike diseases 57

X-disease 58

Little cherry ^ _ 59

Albino _ _ 61

Prunus ringspot ^ „ _ _ _ 62

Mottle leaf 62

Rusty mottles 63

Rasp leaf 64

Twisted leaf _ 64

Black canker 64

Spur-inducing virosis _ _ _ 65

Short-stem virosis . 65

Virus diseases of lesser importance 65

Cherry boron rosette Ç>Q

Other disease problems 66

Harvesting and marketing 67

Picking maturity „ _ 68

Indices of maturity ^ _ 68

Fruit handling „ 69

Packaging 69

Pretransit holding and shipping _ _ 72

Processing .. _ 74

Brining 74

Maraschino 81

Glacé _ 84

Canning 84

Freezing 85

Dehydrating _ _ _ 85

Pickling „. _ 85

Other uses _ 85

Literature cited „ 85

Additional selected references _ 91

II
Sweet Cherries: Production, Marketing, and Processing

By H. W. FOGLE; J. C. SNYDER,' H. BAKER/ H. R. CAMERON/

L. C. COCHRAN,' H. A. SCHOMER," AND H. Y. YANG '

INTRODUCTION

Climatic conditions in the Pacific Coast

S ;ates are very different from those in the

Great Lakes cherry areas. Cultivars (varieties

d(îveloped under cultivation) grown are different in the western and eastern growing regions. Utilization varies widely, even among

the Pacific Coast States. Many western cherries

ai'e grown under irrigation, while those in eastern orchards are grown mostly under natural

rainfall. The western shipper requires cultivars firm enough to withstand transportation

f(>r 3,000 miles and several days on the grocer's

shelf, whereas the eastern grower uses softflashed cultivars because of their greater rainci'acking resistance.

Despite these variations between growing

rcîgions, it appeared desirable to have a publication combining such recent developments as

n^w cultivars and new harvesting and handling

rrethods with the considerable, but widely dispersed, published material on sweet cherries.

Since about 80 percent of the sweet cherries

are produced in the Western States, it appeared

^ Research horticulturist, Fruit Laboratory, Northeastern Region, BeltsviUe, Md.

- Deceased. Formerly Extension horticulture specialist, Washington State University, Pullman, Wash.

^ Retired. Formerly assistant chief, Fruit and Vegetable Insect Research Branch, Entomology Research

Division, Agricultural Research Service.

' Plant pathologist, Oregon State University, Corvallis, Oreg.

^ Retired. Formerly chief, Fruit and Nut Crops

Research Branch, Plant Science Research Division,

Agricultural Research Service, Beltsville, Md.

" Retired. Formerly plant physiologist. Market Quality Research Division, Agricultural Research Service,

W~enatchee, Wash.

' Food technologist, Oregon State University, CorVcdlis, Oreg.

logical to prepare such a publication primarily

for western conditions, with variations noted

as appropriate for eastern producing areas.

The sweet cherry is considered to be native

to the Caspian-Black Sea region (30)^ and

perhaps to parts of Asia as far east as northern India (58), From these areas, men and

birds apparently spread seeds to all of continental Europe.

Early colonists brought sweet-cherry seeds

to America and established orchards. Natural

spread occurred in the eastern United States,

and large specimen trees were often found in

open pastures or forests. Propagation of trees

by grafting in America started about 1767,

some 140 years after the first records of cherry

culture in America (71).

Settlers brought sweet cherries with them

to Michigan, Indiana, Illinois, and Missouri in

the period from 1700 to 1750.

Franciscan monks were cultivating sweet

cherries in California missions by the end of

the Revolutionary War. A few of the ''fortyniner" gold miners began cultivation of cherries and other fruits. However, modern cherry

growing in the West began with Henderson

Lewelling, who in 1847 transported nursery

stock from Iowa to western Oregon by oxcart

and established orchards. Later, lacking suitable understocks, the Lewelling nursery, then

headed by Henderson's brother, Seth Lewelling,

grew large numbers of cherry trees from seeds.

From these, the cultivars 'Bing' and 'Republican', and later, 'Lambert' originated.

'Napoleon' was renamed *'Royal Ann" by the

Lewelling brothers after its label was lost en-

^ Italic numbers in parentheses refer to Literature

Cited, p. 85.

1
AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

route during the overland journey. These four

cultivars have comprised nearly all of the commercial acreage in the West until the present

time.

BOTANICAL CLASSIFICATION

The sweet cherry {Prunus avium L.) is a

drupe or stone fruit belonging to the family

Rosaceae. It has a basic chromosome number

(n) of 8. Nearly all sweet cherries are diploid

(2n = 16), although occasional tetraploids

(4n = 32), which bloom sparsely and are unproductive, occur from the union of unreduced

gametes. Rarely, triploids have been found.

Duke cherries, P. Gondouini (Poit. and Turp.)

Rehder, [{P. effusa (Host.) Schneid.)], arise

from the cross of tetraploid P. cerasus L.

(commonly known as sour cherry, tart cherry,

pie cherry, or red cherry) and unreduced pollen

(2n) of the sweet cherry. The tetraploid duke

cherries are productive in varying intermediate

degrees between the two species.

Numerous attempts have been made to separate sweet cherries into distinct subspecies.

Although some rather distinct botanical differences are evident in the wild state, hybridization of the cultivated forms confuse any such

attempt at classification. Therefore, it is more

practical to separate cultivars into two rather

distinct pomological groups:

1. The bigarreaus, which have firmñeshed fruits, and

2. The Guigne, Gean, or Heart group,

which have soft, tender ñesh.

Only bigarreau-type cherries are firm enough

to withstand commercial handling. Heart-type

cherries often are satisfactory for backyard

use, however.

Both of these groups can be further divided

on the basis of skin color into dark and light

types. The so-called "black" cherries are actually reddish-purple or mahogany, and the

so-called "white" ones are actually yellow, usually with pink blush.

Botanically, cherries are more closely related to plums than to peaches or apricots.

Some borderline Prunus species are difficult to

classify definitely into one or the other group.

Cherries generally differ from plums in that

leaves emerging from buds are folded lengthwise in contrast to being rolled in plums.

Also, in cherries, the stone is more globular,

the fruit and stone are smaller, and the flowers

occur in corymbose, rather than unbelliferous,

clusters.

Sweet-cherry trees that are untrained and

unpruned form a large tree with strong central leaders. Generally, they are long-lived

trees, which will attain greater height and

breadth than can be handled economically in

commercial practice (fig. 1). Hence, some care

in training the young tree, pruning to produce

and maintain wide-angled limbs, and forcing

early fruiting are helpful in controlled growth

and mature tree size. When fully hardened,

sweet-cherry trees are hardier than peaches

but more tender than most apple varieties.

However, trunks, crotches, and terminal wood

of sweet-cherry trees are susceptible to early

fall freezes.

Leaves and fruits of sweet cherries are larger

in general than those of other cherry species.

Petioles may be glabrous or may have sparse

to dense pubescence. Large, prominent glands,

often bright red, occur at the base of leaf blades

and on the petiole.

Flowers are white-petaled and usually single, although double-flowered types occur. InV

PN-3042

FIGURE 1.—A large bearing sweet-cherry tree. Note

the natural spread of the tree as a result of ample

space. This tree regularly produced more than 1,000 lb.

of fruit each year.
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING

florescence buds contain 1 to 5 flowers, usually

2 or 3, forming a shortened corymb upon opening.

Fruits vary from round through ovate to

long heart shapes. The stylar scar often is

conspicuous. The stem cavity ranges from very

shallow with symmetrical shoulders in the oval

shapes to deep, abrupt ones with prominent

shoulders in the heart shapes. Sutures are usually inconspicuous. Flesh color ranges from

yellow to dark purplish-red, almost black, and

is controlled by one genetic factor {26, Í1).

Sl:in color varies from yellow, to yellow with

a pink blush, through shades of mahogany, to

almost black. Although quantitative inheritance of skin color first seemed probable, one

major factor and a hypostatic one appear to

explain the segregation classes that occur (H).

Additional modifying factors may operate.

Stem length may vary from about an inch to

nearly 3 inches. The stone is elliptical to

roundish, smooth, and free to semiclinging to

the flesh. Pits are distinctive morphologically

arid thus are useful in identifying cultivars.

For rootstocks, seeds are used of mazzard, a

term used to denote small-fruited, usually uncí Itivated, P. avium, or of the St. Lucie cherry,

P mahaleb L. The 'Stockton Morello', P. ceratuSy is a preferred rootstock where soils are

too wet for mazzard rootstocks. Other rootstocks that have been used to a limited extent

a]"e P. frtiticosa Pall., (the European ground

cherry), P. fontanesiana Schneid, (a mazzard

X mahaleb hybrid), P. pensylvanica L., P. serrulata Lindl., P. ^^dropmoreana'\ P. incisa

Thunb., P. nipponica var. kurilensis (Miy.)

Wils., and other P. cerasus cultivars.

AREAS OF ADAPTATION

Sweet cherries are not well adapted to most

areas of the United States. Despite the fact

that it has been a favored home garden fruit

and tried in every part of the country, the

sweet cherry is limited in commercial production principally to seven western and four

Great Lakes States. In the last 2 decades, California, Oregon, Washington, and Michigan accounted for about 80 percent of the trees and

more than 85 percent of the U.S. production.

The following compilation (table 1) from USDA Agricultural Statistics and U.S. Census

data shows the distribution of sweet-cherry

production and reveals possible trends in the

United States.

IMPORTANCE OF CROP

The annual U.S. production of sweet cherries

averaged more than 90,000 tons in the years

1951 through 1970, and more than 113,000

tons in the last 5 years of this period. In the

second of these decades, more than 100,000

tons were produced each year except 1963,

1965, and 1968. Peak production of 136,390

tons occurred in 1949, and a similar yield occurred in 1971. The 1970 crop of 121,650 tons

had a farm value of more than 40 million dollars, about an average return from crops in the

past decade. Crop prices are affected by unusually heavy or light crops, and total value tends

to fluctuate less than production.

Almost 3.9 million trees, 37 percent of which

were nonbearing, were reported in the 1964

census, as compared to less than 2.3 million in

1959. Approximately 4.1 million sweetcherry trees were reported in the 1969 census.

Twenty-eight percent of these were nonbearing

trees.

Each of the eight top-producing States showed

increases in the number of nonbearing trees in

1959 as compared with 1954 (table 1). Continued expansion of sweet-cherry plantings

was evident in the 1964 trees census, particularly in Washington, Oregon, Montana, Michigan, and Colorado, but expansion had ceased

in California, New York, and Pennsylvania.

Other producing States were about maintaining

their planting rate. In the Pacific Northwest,

part of the increase was accounted for by replacement of trees lost in the severe fall freeze

of 1955. Most of the rest represent substantial

new plantings in all major sweet-cherry areas,

reflecting the relatively favorable returns of

recent years.

About 35 percent of marketable sweet cherries was sold on the fresh market each year

from 1960 to 1969. Previously about 40 percent

and as high as 48 percent were marketed fresh.

During the period 1955-70, between 10 and 20

percent of the crop was canned, and less than

1 percent was frozen each year. The remaining
TABLE 1.—Percent of total U.S. sweet-cherry production for a 22'year period, percent of total U.S. trees bearing and nonbearing from 1959 and 196Í censuses, and percent change in number of nonbearing trees from 195Í to 1959 and from 1959

to 196Jf, by producing States

Percent of total U.S. trees ^

Change in percent of

Percent of total U.S. production ' Bearing

1959 1964

Nonbearing

1959 1964

nonbearing trees

State 1950-59 1960 1961 1962-(36' 1967 1968 1969 1970 1971^ 1959/1954 1964/1959

Calif - „ 30 34 27 26 15 28 24 21 24 28 25 28 18 + 27 -14

Oreg .._ 24 18 25 25 35 17 28 33 24 23 21 19 23 + 192 + 57

Wash 19 16 21 18 21 13 19 20 24 11 14 11 22 + 127 + 159

Mich 11 20 14 18 16 24 17 17 15 19 23 29 26 + 157 + 12

N.Y 5 5 4 5 4 6 6 3 5 6 5 4 3 + 33 -15

Utah 4 2 2 2 3 8 2 2 3 5 5 4 3 + 33 + 5

Idaho 3 2 2 2 2 1 2 1 1 2 2 2 1 + 20 + 6

Mont 2 2 2 1 2 1 <1 1 2 2 2 2 2 + 223 + 32

Pa ^ _ 1 1 1 1 1 1 1 1 <1 2 2 1 1 -31 -6

Colo 1 1 1 1 1 1 <1 <1 <1 1 1 1 1 -34 + 44

Ohio 1 1 1 1 <1 1 <1 -31 -22

^From Crop Production, Annual Summaries (CR-FR-2-1) and Fruits, Non-Citrus, by States (FR-NT-2-1), prepared by USDA Statistical

Reporting Service, Crops Reporting Board, Washington, D.C. Reporting for Ohio ended in 1961.

'From Census of Agriculture, Vol. II General Report 1959:926-927 and 1964:468-469.

' Average for 5-year period used because of extremely atypical distribution of the crops in 1963, 1965 and 1966.

'Indicated crop, from Crop Production (CrPR 2-2) release dated July 9, 1971, USDA Statistical Reporting Service.

' (Total nonbearing trees in 1959 -^ total nonbearing trees in 1954) x 100 - 100.

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SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING

percentage, as high as 50 percent, was brined

during this same period for manufacture of

maraschino, glacé, and candied cherries.

Use of sweet cherries varies widely in different producing areas. Oregon and the Great

Lake States market about 15 percent of their

production fresh and brine about two-thirds.

California markets about one-third of its production fresh and brines about half. Washington (90) and the remaining western States

market more than two-thirds of their production fresh. Washington divides the remainder

between canned and brined products, while

Montana, Idaho, Colorado, and Utah brine all

of their remainder.

The canning industry uses from 15 to 25

percent of the marketed volume in California,

Oregon, Washington, and the Great Lake

States. Favorable fresh-market prices, unusually large fruit size, and freedom from raincracking reduce the volume for processing,

particularly in the Pacific Northwest States.

Washington is the only State reporting freezing of sweet cherries for market. About 2VÍ»

percent of the cherries sold in Washington

are frozen.

RESPONSES TO CLIMATE

WINTER- AND FROST-HARDINESS

When fully dormant, sweet-cherry trees

withstand minimum temperatures that kill

peach fruit buds and severely damage peach

tr^es. However, cherry trees are very susceptil)le to freezes before the hardening process

is completed. In 1955, many cherry trees in

the Pacific Northwest were killed or severely

di.maged in the trunk and crotches by temperatures around 0° F. in mid-November (fig. 2).

Tliese temperatures would not injure a dormant cherry tree, but they had not been preceded by a killing frost in most areas. Thus

the hardening process was incomplete. Therefore, it is advisable to avoid late flushes of

gi'owth and to promote early tree hardening

by withholding late summer or early fall applications of nitrogen, by avoiding heavy irrigation in the early fall, and by the use of

fall-seeded cover crops.

Sweet-cherry fruit buds sometimes are killed

during the dormant period. *Bing' buds tend to

withstand 2° to 4° lower temperatures than do

those of peach. Occasionally the difference may

be more than 4° because cherry fruit buds respond to below-freezing temperatures more

rapidly than do peach buds in Washington

State tests.

Fruit buds are very sensitive to spring

frosts just preceding and during the opening

of flower cluster buds. Whereas a temperature

of 28° F. is considered critical for cherries

during the tight-cluster stage of flower opening, the other stone fruits may endure 25° F.

or lower. During the bloom and after-bloom

periods, however, cherries will withstand about

as much cold as the other fruits at equivalent

stages of development.

RAIN CRACKING OF FRUIT

Rain during, or just preceding, harvest may

result in cracking of fruits. If the fruits dry

quickly or if temperatures remain cool until

the fruits are dry, cracking will probably not

occur. Often small cracks will heal sufficiently

to allow the fruit to be marketed. However,

large concentric ring splits around the stem

cavity or longitudinal splits across the sides or

stylar end permit the entrance of molds and

extraneous material. The cracked fruit requires

culling during the picking and handling operations, often to the extent that picking costs

are not returned.

Warm rains followed immediately by sunshine are the conditions most favorable for

cracking. Soil moisture content apparently is

not a factor in cracking {126). Instead, osmotic absorption of water through the skin of

the fruit appears to be responsible for cracking. Higher soluble solids (sugars), greater

turgidity of the fruit, warmer water temperatures, and greater skin permeability all favor

cracking.

Cracking of fruits as a result of rains dur-
AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

ing harvest is a major factor limiting the distribution of sweet-cherry production. While

large differences in rain-cracking resistance

between cultivars do not exist, this hazard can

be somewhat reduced by selection of cultivars.

The 'Bing' cultivar is quite susceptible to cracking and is not adapted to many fruit-growing

areas for that reason. On the other hand, 'Bing'

is the leading cultivar in the western States,

where its firmness for long-distance shipping

overshadows the cracking hazard. 'Lambert'

appears susceptible to fruit cracking in the

PN-304S PN-3044 PN-3045 PN-3046

FIGURE 2.—Recovery of cherry trees by May 1956 from the fall 1955 freeze in the Pacific Northwest. Progressively less damage and greater recovery are shown by trees of A, 'Bing', B, 'Lambert', C, 'Sam', and D, 'Van'.
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING

"green" stages, but less so than *Bing' in riper

stages. 'Van', 'Sam', and 'Hedelfingen' under

field conditions have appeared more crackresistant than other firm-fleshed cultivars.

A number of preventive sprays have been

tried to reduce rain-cracking of fruit. Among

these were rosin, fish-oil soap, casein solution, casein and tannin mixtures, and lime

spra {127). Each of these under certain conditic. somewhat reduced fruit cracking but

ler't .xidesirable residues. Cracking was reduced 50 to 60 percent on trees with full crops

arid somewhat less on trees with light crops

wlien 1 p.p.m. naphthalene acetic acid (NAA)

siirays {13) were applied midv/ay between

blossoming and harvest (or about 30 days after

fill bloom). Oregon tests {ISJp) confirm the

effectiveness of NAA sprays and show reducti )n of fruit cracking from sprays of hydrated

li:Tie (5 to 8 lb. per 100 gal.) two weeks before

harvest. These lime sprays are suggested only

for fruit to be brined.

FRUIT DOUBLES

Fruit doubles reflect the occurrence of two

p.stils on a single pedicel. If the ovaries of

both pistils are fertilized and normal developn^ent progresses, two fleshy fruits ripen on the

same fruit stem. If one of the ovaries is not

f(irtilized, a normal fruit will develop. If one

developing ovary aborts, a fleshy cherry with

a 1 attached dry fruit occurs. If neither pistil

is fertilized or both ovaries abort, the pedicel

drops.

Seasonal differences are found in the occurrence of fruit doubles or twin fruits. These occur as more or less equally developed cherries,

or one member of the twin may not develop

fully, forming a fleshy or dry, hard protuberance on the side of the normal cherry. Usually

the undeveloped fruit cannot be separated from

the normal one without tearing the skin of the

latter, rendering it unmarketable. If this type

of fruit is not culled during harvest, the undeveloped twin punctures good fruit in the

picking container. Excessive doubles may make

sorting impractical, and the whole crop becomes unmarketable. Normally a few doubles

are not discriminated against in the market,

providing both cherries of most twins are

fleshy.

Multiple pistils form because of one or occasionally two additional cell divisions during

the fruit bud initiation period. Unusually

warm weather during the fruit bud initiation

period, late May or early June of the season

preceding blossoming, influences the occurrence of doubles. Hot periods in July and August are thought to produce 20 to 30 percent

fruit doubles in the *Bing' and ^Napoleon' cultivars in the Sacramento Valley of California

{86). Doubles rarely occur, however, in the

cooler coastal valleys of California. Most

doubles tend to occur on the southwest side of

the tree and in the terminal 3 feet of the

branches.

Some control over the occurrence of doubles

can be exercised by the choice of orchard site.

Areas or sites particularly subject to high temperatures (90° F. or over) during late spring

and early summer can be avoided. It should be

remembered, however, that warm, irrigated

areas are generally less subject to rain-ernckiiig

and diseases. A dense cover crop, if compacible with the cultural system used, may help

to moderate temperatures in the orchard during this period of flower bud formation.

SOIL REQUIREMENTS

Sweet cherries on mazzard {Prunus aviwm)

rootstocks are not tolerant of clay or poorly

drained soils. Trees grow best on sandy loams,

particularly those that do not have clay or

caliche layer subsoils. Heavier soils often are

satisfactory if surface and subsoil water drain-

£ ge is good. Shallow sandy soils, particularly

those where irrigation is not available, are not

suited to sweet-cherry production.

Trees on mahaleb rootstocks (P. mahaleb L.)

are more tolerant of sandy soils, soil-moisture

deficiencies, and high alkalinity than trees on

mazzard stocks. Trees on 'Stockton Morello*

sour-cherry rootstock (P. cerasus), on the
8

AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

other hand, are less susceptible to damage from

wet soils than trees on either mahaleb or mazzard stocks. In Oregon, ^Napoleon' trees on

morello rootstocks have tended to be short lived.

Soils that recently have been planted to

crops susceptible to the Verticillium wilt fungus

should be avoided. Sweet cherries are subject

to attack by the same species (Verticillium

albo-atrum Reinke & Berth.) as are apricots,

almonds, potatoes, tomatoes, eggplant, melons,

mint, cotton, tobacco, the brambles, and some

orchard weeds and cover crops. Before planting a sweet-cherry orchard, a grower should

determine whether any of these crops have

been used on the proposed orchard site in the

previous 10 to 15 years. Land previously used

for potatoes particularly should be avoided.

The fungus is known to persist in the soil even

though nonhosts have intervened for several

years. Fumigation may be feasible if a particularly desirable site is known to have grown

susceptible crops.

On old apple land with high content of arsenic, it is desirable to haul in soil to replace

the contaminated soil in each tree hole.

CULTIVARS (VARIETIES)

Selection of main cultivars best suited to the

environmental, cultural, and marketing factors that affect his operation is probably one

of the most important decisions a grower makes.

Successful sweet-cherry production requires

that the cultivars be adapted to the environment. The grower must consider the coldhardiness of wood and fruit buds; resistance to

rain-cracking, diseases, and insects; and compatibility with the rootstock dictated by climate and soil type.

Other important considerations include time

of fruit maturity, rainfall hazard during ripening and harvest, and the availability of facilities and labor at harvesttime. Available market

outlets should be investigated to determine the

marketing arrangement most advantageous to

the grower. In selecting cultivars, the grower

should exploit advantages such as large fruit

size, earliness, and closeness to markets. Consumer preferences in the available markets

should be considered.

About 1,150 cultivars of cherries, almost

half of them sweet cherries, have been described (58). A listing by the American Pomological Society (iJ^) contains almost 300 cultivars under cultivation at United States and

Canadian experiment stations. Numerous selections of known hybrid origin or unknown parentage also are under test. A few mutants,

notably 'Rainbow Stripe', which mutated from

'Lambert', and a similar light-colored mutant

from *Bing', have occurred naturally. Both mutants have fruits of 'Napoleon' type but with

dark suture lines.

Despite the large number of cultivars available, only 'Bing', 'Lambert', 'Napoleon' (Royal

Ann), and 'Black Tartarian' were used to any

extent for commercial production in the West

until interest in new varieties intensified about

1940. 'Republican', 'Deacon', 'Van', 'Sam', 'Centennial', 'Waterhouse', mazzard seedlings, and

others were used primarily as pollinizers.

'Schmidt', 'Windsor', 'Lambert', 'Napoleon',

'Victor', and 'Black Tartarian' have been the

favored cultivars in the East.

Increased interest in cultivars has led to

the use of newer ones as main cultivars rather

than as pollinizers only. Objectives have been

to spread the harvest season and to take advantage of the hardiness and rain-cracking

resistance available in some of the newer cultivars.

Descriptions of main commercial, specialpurpose, and promising new cultivars follow.

The new cultivars should be planted with standard cultivars to determine their performance

in the environment and the cultural management system of the individual grower. Some

are described only brieñy because of limited

data on their performance.

MAIN CULTIVARS

'BING', with its large, firm, reddish-purple

(mahogany) fruit is the principal cultivar of
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 9

the sweet-cherry industry. The 'Bing' cultivar

originated from a seed of 'Republican' grown

by Seth Lewelling of Milwaukie, Oreg., in 1875.

It was named after a Chinese workman (58).

The fruit, as it is grown in the Pacific Northwest, represents about the ideal type desired

by handlers. The fruit is firm enough for longdistance shipping—up to 3,000 miles. Fruit

size, under careful management, often averages 1% inches in diameter or larger, giving

the handler a high percentage of 9- to 11-row "

boxes (fig. 3). The fruit color is very desirable,

and it remains lustrous until the fruit is overripe. The stem length is average, II/2 to 2

inches, permitting easy picking. The high sugar

content of 'Bing' fruits is balanced by a relatively high acid content, resulting in a distinctive, tangy flavor. The stone is relatively

small, and the flesh is thick, crisp, red, and

juicy. On the other hand, the fruit is susceptible to rain-cracking, doubling, and brown rot.

Fruit ripens in early midseason. It is round to

heart-shaped, with a prominent stylar scar

and an inconspicious suture line. The stone is

semicling to almost free, oval, and smooth.

The tree, while reasonably vigorous in the

West, lacks winter-hardiness and is susceptible to a number of virus and viruslike disorders. Trees of 'Bing' are upright-spreading in

growth habit. Crotches usually are wide-angled

and strong. Bark is reddish-brown and smooth,

with gray scarfskin. Bark lenticels are large

and conspicious. Leaves generally are oblong

ovate, coarsely crenate, and dark green. Leaf

petioles are glabrous; this characteristic is

used for nursery identification of nonbearing

trees.

The cultivar is self-incompatible and incompatible with 'Lambert', 'Napoleon', and 'Emperor Francis'. Other cultivars generally pollinize 'Bing' adequately, providing they overlap

its blossom period. 'Van', 'Deacon', 'Republican', and 'Sam' (where this cultivar does not

bloom too late) have been particularly useful

as pollinizers for 'Bing'.

" Row-size number refers to the number of cherries of

uniform size required to fill the width of a standard

cherry lug (11.5 inches). This requires an average

diameter of 1%2 inch for 9-row, 1%2 inch for 10-row,

and 1%4 inch for 11-row cherries.

FIGURE 3.—A packed box of 10-row sweet cherries-

'Chinook' cultivar.

'LAMBERT', with its large, medium firm,

dark fruit is more widely adapted than 'Bing'.

Trees are more vigorous and hardier than

'Bing'. The growth habit is more upright than

'Bing', and crotch angles tend to be narrower.

'Lambert' originated as a seedling of 'Napoleon' on the Henderson Lewelling farm at

Milwaukie, Oreg., about 1880. The pollen parent was thought to be 'Black Heart'. It was introduced by J. H. Lambert in 1895 (58).

Fruits of 'Lambert' are moderately firm,

slightly lighter in color than 'Bing', and more

lustrous, juicier, milder in flavor, and lower

in soluble solids than those of 'Bing'. The cavity is deep and flaring. The stylar scar is depressed. The fruit ripens on an average of a

week later than 'Bing'. The fruit shape is longer

and more pointed than 'Bing'. It is firm enough

for distant shipping and suitable for processing.

The stem is longer and slender. The stone clings
10 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

and is large and slightly flattened. The skin is

thin but tough.

The tree is erratic in bearing in eastern

areas. The fruit does not hold well on the

tree, and, in fact, sometimes shatters from the

stem. The fruit is subject to rain-cracking.

Green fruits and very ripe fruits probably

are more susceptible to rain-cracking than

'Bing', but *Bing' is more susceptible during

the early harvest period. Pruning and training

are more difficult with 'Lambert' than with

*Bing', because of the more upright growth of

the former. Narrow angles tend to form, and

long barren branches may occur. The bark is

reddish-brown, with numerous lenticels, giving

an overall grayish appearance. Leaves are

large, oblong-oval to obovate, and finely serrate. Petioles have numerous hairs.

'NAPOLEON' (Royal Ann) has a clear to

yellow flesh, with yellow skin and a variable

amount of pink blush. It originated in Europe

of unknown parentage. It was first described

in France, apparently about 1667, under a

different name. Seth Lewelling renamed it

Royal Ann following loss of the label during

the wagon trek of the Lewelling brothers to

Oregon (58). This name persists in the western States.

The tree is somewhat more spreading than

'Bing'. Although the tree and fruit buds are

relatively hardy when dormant, the cultivar

appears particularly susceptible to early fall

freeze damage. Young trees are vigorous, but

there is a tendency for older trees to become

slow growing and overproductive. Branches

usually are wide-angled with strong crotches.

The bark is reddish-brown and often is covered by gray scarfskin. Lenticels are large

and prominent. Leaves are long, tapering to

a fine point, finely serrate, and semifolded.

'Napoleon' fruit ripens a few days earlier

than that of 'Bing'. It is moderately firm

fleshed, juicy, lower in soluble solids, and

similar in acidity to 'Bing'. It is very susceptible to doubling in warm climates. The overall

flavor is mild but slightly acid. The fruit is

particularly well adapted to canning and brining. However, it is not adapted to longdistance shipping because of its tendency to

show brown skin bruises from handling or

preharvest wind damage.

'SCHMIDT' is the preferred cultivar in areas

where 'Bing' is not successfully grown because of excessive rain-cracking or lack of

vigor. It is a main cultivar in eastern orchards,

but is not considered productive enough in

the West.

'Schmidt' originated about 1841 as a seedling of an old German cultivar and was raised

by a forester named Schmidt at Casekaw,

Prussia, Germany. It was introduced into

England by Thomas Rivers and then to

America, but the details are unknown (58).

The name appeared on the American Pomological Society list in 1897.

The fruit is large, dark mahogany, roundish

cordate, and flattened on the ventral side,

with a slight swelling along the suture. The

stem is medium long, up to 1% inches, and

moderately slender. The stem cavity is deep

and flaring. The suture is a black line. The

stylar scar is small and dark. The skin is

thick and tough. The flesh is firm, wine red

in color, and meaty. The flavor is sweet and

rich but rather astringent. The stone is clinging and large sized. The cultivar usually ripens

a few days before 'Bing'.

The tree is large, vigorous, and uprightspreading. The bark is purplish-brown and

often covered with scarfskin. Lenticels are

numerous, large, prominent, and brown, which

gives the tree a characteristic striped and

rough appearance. Fruit buds and blossoms

are relatively tender, but the tree is hardy.

Leaves are very large, oblong-ovate, and finely

serrate. Rain-cracking of fruit is less serious

than in 'Bing' or 'Lambert'. 'Schmidt' is a

good pollinizer for 'Bing', 'Lambert', and

'Napoleon'.

'WINDSOR' is the standard late-ripening,

dark cherry in eastern areas. Generally in

the West this cultivar is not used because of

its small size and also because it is softer

and has lighter-colored flesh than either 'Bing'

or 'Lambert'. In the East its bud hardiness

and regular, heavy productivity have generally

outweighed the usual discount in the price

of this cultivar in comparison to the larger,

firmer 'Bing' fruits. It should be considered
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 11

for home-orchard plantings, particularly in

districts subject to low winter temperatures.

Windsor' originated on the farm of James

Dougall of Windsor, Ontario, Canada (58).

It was first propagated in 1881.

The fruit is medium to large, round to

round-ovate, and laterally compressed. The

flesh is relatively softer than 'Lambert'. It

ripens late, usually after 'Lambert'. The stem

cavity is deep, wide, and flaring. The suture

is indistinct. The stylar scar is a mediumsized russet dot which is slightly depressed.

The skin is red, becoming purplish-black when

fully ripe. The flesh is tender, red to purple,

meaty, and subacid to sweet. The quality is

fair to good. The stem is short to medium,

1 to 11/2 inches, and adherent to flesh until

fully ripe.

The 'Windsor' tree is medium-sized, vigorous, spreading, hardy, and very productive.

The bark is reddish brown, and on older

branches it is covered with gray scarfskin.

Lenticels are small, oval, and scattered. Leaves

are medium sized, oblong, and coarsely serrate.

SPECIAL-PURPOSE CULTIVARS

Although the five cultivars described in the

preceding section represent nearly all the commercial acreage, several other cultivars are

important to provide the necessary pollination of the main cultivars or for specialpurpose use. Some of these are gaining limited

favor as main cultivars in some areas. These

are described in the approximate order of

ripening.

'SENECA' is distinctive because it ripens

2 to 3 weeks ahead of 'Black Tartarian'. The

fruits are of 'Black Tartarian' type, but are

too small and soft for commercial use. It is

a good pollinizer and has backyard possibilities. The term "bird cherry" is used colloquially for this cultivar, because the fruit

ripens earlier than other varieties and birds

harvest most of the crop.

'Seneca' originated from a cross in 1910

of Early Purple and an unknown red-skinned

sweet cherry. It was introduced about 1922

])y the New York State Agricultural Experiment Station (12), The tree is tall, spreading,

and very vigorous. It is relatively hardy, precocious, and productive. Leaves are narrow,

crenulate, and coarsely serrate.

The fruit is small and somewhat truncate.

The stem cavity is moderately deep and flaring. The skin is thin and tender, and the

flesh is dark red, juicy, soft, and slightly

stringy.

'EARLY RIVERS' and 'EARLY PURPLE'

(Guigne) are very early cultivars ripening

between 'Seneca' and 'Black Tartarian' seasons. 'Early Purple', which was first mentioned in 1688, apparently originated in

England as a result of a cross of May Duke

and Spanish Yellow. 'Early Rivers' is a more

recent English introduction (58), Both are

of 'Black Tartarian' type but earlier than

that cultivar. 'Early Rivers' has firmer fruit

than does 'Black Tartarian'.

'BIGARREAU DE SCHRECKEN' is a

dark-fleshed cherry that ripens about 2 days

before 'Black Tartarian'. It is a German

cultivar tracing back at least to 1876 (58),

The fruit flesh is firmer than that of 'Black

Tartarian', and therefore the fruit is better

adapted to shipping. Fruit size tends to be

small, flavor is relatively poor, and excessive

doubling may occur.

'LYONS' originated near Lyons, France,

in 1822 (58). It is an early, medium-large,

dark cherry with tender flesh. The tree tends

to have a weeping habit.

'BLACK TARTARIAN', the standard cultivar for the early season, was introduced into

England from Circassia, Russia, under the

name of Ronald's Large Black Heart. It was

first introduced into America by William

Prince of Flushing, N.Y., early in the nineteenth century (58). It is probably the most

widely disseminated sweet-cherry cultivar in

the world.

The tree is vigorous, productive, and upright. Crotches tend to be narrow, crowded,

and weak. The tree is not very hardy, particularly to early -fall freezes, but fruit buds

are fairly hardy. The bark is reddish-brown

and smooth. Lenticels are large, numerous,

conspicious, raised, and sharply pointed.

Leaves are large, lanceolate, with coarsely serrate margins. Glands, usually 2 to 4, occur
12 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

on the petiole below attachment to the leaf

blade.

The medium to small fruits ripen early and

hang in good condition for some time. The

skin is thin, separates readily from the flesh,

and becomes very dark, almost black. The

flesh is soft, dark red, juicy, highly flavored,

and sweet. The juice is dark and abundant.

The stone is free, smooth, and slightly compressed laterally.

^VICTOR', a Windsor' seedling, was introduced in 1925 by the Horticultural Experiment

Station, Vineland, Ontario, Canada (12). This

light-colored cherry ripens 3 to 4 days before

'Napoleon'. The tree is large and vigorous

but is not productive in all areas. The fruit

is medium large, relatively firm fleshed, and

of good quality. Usually this cultivar has more

pink blush on the fruit than 'Napoleon' has,

and it is sometimes preferred for this reason.

'SPATE BRAUNE' is a dark-skinned, lightfleshed cultivar of unknown European origin,

which ripens a few days before 'Bing'. The

fruit is firm and of good quality and has a

long stem. The tree is very productive.

'VAN' was selected in 1942 by A. J. Mann

at the Research Station, Summerland, B. C,

Canada. It is an open-pollinated seedling of

'Empress Eugenie', a Duke cherry. It is named

in honor of J. R. Van Haarlem, former pomologist at the Horticultural Experiment Station

at Vineland, Ont. (12), This dark cherry has

numerous good characteristics. It has proved

one of the most satisfactory pollinizers for

'Bing', 'Lambert', 'Napoleon', and many other

cultivars. It showed outstanding tree hardiness

to the 1955 fall freeze in central Washington.

'Van' appears to have some rain-cracking resistance. The tree makes vigorous nursery

growth. The tree is precocious, bearing commercial crops after 4 or 5 years in the orchard,

or 1 to 3 years before the 'Bing' cultivar.

The fruit colors early and retains a bright

lustrous color over a long picking period (7

to 10 days). The fruit is high in soluble solids

and retains its high quality and firmness

into 'Lambert' season. It is adapted to canning,

although the flesh tends to be a lighter color

than 'Bing' unless harvesting is delayed until

'Lambert' season. Picking for fresh market

may be done in 'Bing' season or slightly earlier

because of Van's early coloring and high soluble solids. Increased size and darker flesh

color, without substantial loss of the bright

luster, favors picking after 'Bing', however.

'Van', perhaps more than any other cherry

cultivar, responds favorably to special cultural

practices. The tree should be maintained in

high vigor and pruned more selectively than

normally is practiced to assure continued production of large fruit. Its tendency to overproduce should be recognized. It has special

merit as a filler ^° cultivar because of its heavy

production during the early years of the

orchard. There are indications of possible incompatibility with the P. mahaleb rootstock

US), The cultivar does not grow satisfactorily

in areas where bacterial canker is severe. The

fruit stem is short, and fruits tend to form

a tight cylinder around the branch. Both factors may contribute to diflicult picking. The

fruit shape is blocky (short linear axis) as

contrasted to the heart shape of 'Bing'; consequently, it requires more fruits of 'Van'

than of 'Bing' of comparable row size (shoulder diameter) to fill a box. The framework

of 'Van' trees is less upright than that of

'Bing', and crotch angles usually are wide and

strong.

'NOBLE' (St. Margaret, Tradescant Heart)

is an old, dark-fleshed, English cultivar of

unknown origin (12). It was introduced into

the United States in 1943. The fruit ripens

between 'Schmidt' and 'Hedelfingen' seasons.

It is heart-shaped, large, firm, and sweet. It

rain-cracks less than most late cultivars. The

tree is large and vigorous.

'DEACON' is a dark-colored cultivar that

originated near Olympia, Wash., around 1925

from unknown parentage. It proved to be a

good pollinizing cultivar for 'Bing' and 'Lambert' and was planted in the Pacific Northwest

for that purpose. The fruit exterior closely

resembles that of 'Bing', but the flesh is lighter

red, has lower acidity, and has a milder flavor.

Also, the tree has proved rather slow growing

"^ Fillers are temporary trees planted between permanent trees to make better use of orchard space. These

should be removed before they crowd the permanent

trees.
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 13

and particularly susceptible to disease and to

rain-cracking. The canned product of 'Deacon'

harvested at maturity comparable to *Bing'

has a considerably lighter color and less flavor.

'HEDELFINGEN' is an old German cultivar. Conflicting reports on the rain-cracking

resistance of this cultivar arise from the

existence of tvv^o strains in Germany, only

one of which has rain-cracking resistance.

The collection of this cultivar grown at the

Irrigated Agricultural Research and Extension Center near Prosser, Wash., showed

fairly good resistance to rain-cracking. It

lacked sufficient hardiness, however, to survive

the severe fall freeze of 1955.

The fruit is firm, dark mahogany, and of

good quality. It ripens between 'Bing' and

'Lambert/ seasons. Flavor is slightly astringent, similar to 'Republican', and fairly strong.

The tree is spreading and has slender, slightly

drooping terminals and branches.

'VERNON' is a dark-fleshed, open-pollinated

seedling of 'Windsor' selected in 1925 and

introduced in 1937 by the Horticultural Experiment Station at Vineland, Ontario (12).

The fruit is similar to 'Windsor' in appearance, but larger, firmer, and of higher quality.

[t ripens a few days before 'Bing'. It appears

o be more susceptible to rain-cracking than

s 'Windsor'. The tree is large, vigorous, and

precocious.

'REPUBLICAN' (Black Republican, Leweling, Oregon Black) is a dark-colored, highly

flavored sweet cherry originating about 1850

is a seedling in the orchard of Seth Lewelling

at Milwaukie, Oreg. (58). Although the parentage is unknown, it is thought by some to

be a cross of 'Napoleon' and 'Black Tartarian'

and by others to be a seedling of 'Eagle'.

'Republican' is a dependable pollinizer. Its

tendency to overbear usually results in small,

unprofitable fruit sizes. Skin color becomes

a dull, very dark mahogany, detracting from

the market attractiveness of the fruit. The

flesh is very firm, dark red, and slightly astringent. The tree is more spreading than

'Bing'. 'Republican', topworked at 30 inches

on mahaleb rootstock at the Irrigated Agriculture Research and Extension Center, Prosser,

Wash., overgrew the rootstock within 5 years

and started overbearing, with resultant loss

of commercial fruit size. The mahaleb portions of the trunks were killed by the 1955

fall freeze.

'GIANT' was originated in 1900 by Luther

Burbank and introduced in 1914 (58), It is a

large-fruited, Bing-type cherry, which ripens

after 'Bing'. The fruit is dark, glossy red, and

of good quality. The tree is vigorous and

upright, but it is not as productive as most

cultivars. The trees is slow to start bearing.

'BADACSONY' (Badacsoner Reisenkirsche)

is a large-fruited, firm cherry. It originated

near Balston Lake, Hungary, probably about

100 years ago (58), The fruit is mild flavored

and has light red flesh and a long slender stem.

It ripens about the same time as 'Bing'. The

tree is vigorous, fast growing, and precocious.

It tends to be a shy bearer in California.

NEW AND PROMISING

CULTIVARS

Several cultivars originating within the

last 30 years are relatively untested under

commercial conditions. These are suggested

for commercial trial, but not for large-scale

plantings until their commercial characteristics have been determined. Some have special

merit as pollinizers for present cultivars.

'LAMIDA', a 'Lambert' seedling, was one

of three dark cherries introduced by the Idaho

Agricultural Experiment Station in 1946

(128). It was released because of its resistance to rain-cracking. The fruit is somewhat

more pointed than that of 'Lambert', softer

fleshed, and usually larger. The fruit stem

often is attached to the fruit at an oblique

angle. Soluble solids in this cultivar are relatively low, and the flesh tends to be light red.

The tree does not set as heavy crops as does

'Lambert'. It is somewhat less hardy, although

it is relatively vigorous. This cultivar is very

susceptible to fruit doubling.

'EBONY', another Idaho introduction,

closely resembles 'Republican', but is somewhat larger-fruited. It is a seedling of 'Lambert'. 'Republican' is probably the pollen

parent. The name is derived from the very
14 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

dark skin color. The fruit ripens in *Bing'

season or slightly earlier. Fruit quality is

good, with considerable astringency. Raincracking susceptibility is similar to that of

'Bing', and probably worse during early years

of production when the crops may be small.

The tree is fairly productive, but slow to start

bearing. The cultivar is susceptible to fruit

doubling and to deep suture. The tree is only

moderately hardy.

^SPALDING\ the third Idaho introduction,

was selected from a progeny of 'Bing'. 'Deacon' was the probable pollen parent. It is a

crisp-fleshed, large-fruited cultivar, which

ripens in 'Lambert' season or later. The cultivar is named after a missionary who introduced fruit growing in northern Idaho. The

fruit has a good finish and retains its luster

after picking. The quality is fair, and the

soluble solids are low. The tree is vigorous,

moderate in hardiness, and slow to start bearing. The light crops on young trees rain-crack

easily. With comparable crop, 'Spalding' appears about as susceptible as 'Bing' to raincracking.

'SAM' is a dark-colored cultivar introduced

by the Research Station, Canada Department

of Agriculture, at Summerland, British Columbia {70), The name is derived from the

initials of Summerland and Arthur Mann, a

station fruit breeder who made the selection.

'Sam' resulted from open pollination of a

'Windsor' seedling.

'Sam' fruit ripens about a week earlier than

that of 'Bing'. It is large and conic to heart

shaped. It has dark mahogany skin, firm flesh,

good texture, and some rain-cracking resistance, but relatively low soluble solids and

acid contents. It cans well, producing a syrup

about as dark as 'Bing' with a milder flavor

than that of 'Bing'.

The tree is vigorous, upright-spreading, and

hardier than 'Bing'. In the 1955 fall freeze

in Washington, 'Sam' ranked second only to

'Van' in cold-hardiness. It is a good pollinizer

for 'Bing', 'Lambert', and 'Napoleon' in northern areas where 'Sam' blooms early enough

to overlap the blossoming period of these

cultivars. In one year, however, in the Yakima

Valley of Washington, 'Sam' bloomed too

late to pollinize 'Bing' because blossoms in

the lower part of the trees ^.ere damaged

by frost.

'STAR' is a dark-fleshed introduction from

the Research Station, Canada Department of

Agriculture, at Summerland, British Columbia. It is an open-pollinated seedling of 'Deacon', selected by A. J. Mann and introduced

in 1949 {12). 'Star' is similar to 'Sam' but

appears to be slightly earlier and of better

quality. It has the disadvantage of being unfruitful with the 'Bing', 'Lambert', and 'Napoleon' cultivars, and therefore is unsuited as

a pollinizer in the main western plantings.

It pollinizes 'Van' satisfactorily. It blooms

very late and may not overlap blossoming

of main cultivars sufficiently.

The fruit tends to be Lambert-shaped, but

otherwise it resembles 'Bing' in size, firmness,

and quality. The tree is moderately vigorous,

productive, and moderately hardy. Excessive

fruit doubling and rain-cracking occur in

this cultivar in California.

'LAMBERT COMPACT', tested as Summerland 2B-17-4, was selected from seedlings

grown from irradiated dormant scions of

'Lambert' in 1959. It was introduced in 1964

by K. 0. Lapins {65), The fruit is reported

to be almost identical to that of 'Lambert',

except for slightly shorter and thinner stems

and 2 to 5 days later ripening. The salient

feature of this induced mutant is the compact

growth habit, characterized by short internodes and closely spaced fruit spurs. The tree

is estimated to attain about one-half the size

of 'Lambert' trees.

'STELLA', tested as Summerland 2C-27-19,

is the first self-fertile sweet cherry named.

It originated from the cross in 1956 of 'Lambert' X John Innes seedling 2420. It was selected

in 1964 and named in 1970 by K. 0. Lapins.

The tree is very vigorous, precocious, and

moderately hardy. Fruit is a dark, moderately

firm, large 'Lambert' type. It ripens a week

before that of 'Lambert'. Tests indicate that

'Stella' is self-fertile and a universal polinizer {66),

'STARRING HARDY GIANT' (Meyer)

was discovered in 1925 as a seedling of unknown parentage near Cedarburg, Wis., by
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 15

Mrs. 0. R. Meyer (12), It was granted plant

patent 764 in 1947, introduced as Meyer in

1948, and renamed in 1949 because of its

apparent hardiness and consistent productiveness. The fruit ripens between 'Bing' and

'Lambert' seasons, and closely resembles the

latter cultivar. Skin color is dark but lustrous

and attractive. Flesh color is lighter than

that of 'Bing'. Fruit size often is small because

of the heavy bearing characteristic of this

cultivar. With comparable crops, fruit size

of *Starking Hardy Giant' is almost equal

to well-grown fruits of the 'Bing' and larger

in areas where 'Bing' is not well adapted.

Soluble solids and acidity are lower than in

'Eing', and the flavor is milder.

Trees of 'Starking Hardy Giant' are vigorous, hardy, and very productive. The tree is

uiright in growth habit.

'SUE' is a light-fleshed introduction of the

Summerland Research Station in British Columbia. It was selected from the cross 'Bing'

X 'Schmidt' by A. J. Mann in 1946 and

introduced in 1954 (12). It was released primarily because of its outstanding resistance

to rain-cracking. Otherwise the cultivar is similar to 'Napoleon'. The cultivar is overproduct:ve to the extent that fruit size often is

very small. The relatively soft fruits ripen

about a week earlier than those of 'Napoleon'.

'VISTA' is one of three new cultivars introduced by G. H. Dickson of the Horticultural

Fxperiment Station at Vineland, Ontario, in

1959. It originated from the cross 'Hedelfingen' X 'Victor' and was selected in 1947 (33).

It was released as a possible replacement for

'Black Tartarian' because of larger fruit, better firmness, and brighter, more attractive

finish.

'VENUS' was also introduced by the Horticultural Experiment Station at Vineland,

Ontario, in 1959. It is also from the cross

'Hedelfingen' x 'Victor' and was selected in

1950 (33), The fruit ripens about 5 days

after that of 'Vista'. The fruit is less firm

but more resistant to rain-cracking than that

of 'Vista'. The tree shows a tendency to overset in some years.

'VIC is the third, and potentially the best,

of the three Vineland station introductions

in 1959. It is from the cross 'Bing' x 'Schmidt'

and was selected in 1937 (33), The fruit

ripens at the same time as 'Windsor'. The

cultivar was introduced as a possible replacement for 'Windsor' because of its larger fruit

size and darker flesh color. 'VIC' is reported

(33) to be superior to 'Windsor' in canning

tests and satisfactory for freezing and brining. The tree is large, vigorous, and productive.

'VEGA', a seedling of 'Bing' x 'Victor',

tested as Vineland 31034, was introduced by

the Horticultural Experiment Station at Vineland, Ontario, in 1968. It is described as a large,

attractive, 'Napoleon'-type cherry, adapted to

processing and brining. It has firm fruit and

small pits. The fruits ripen a day before

'Venus'. The fruits can be pitted without detaching the stem and thus are well adapted

to use for cocktail cherries. Flavor is tart

until the fruits are fully ripe (10).

'VALERA', a seedling of 'Hedelfingen' x

'Windsor' tested as Vineland 350427, was also

introduced by the Horticultural Experiment

Station at Vineland, Ontario, in 1968 (10),

A sister seedling of 'Venus', it ripens about a

day later and has darker fruit color, richer

flavor, and more consistent productiveness

than does 'Venus'. The tree is vigorous and

early-bearing. It is suggested for fresh market

use.

'CHINOOK' was jointly introduced by the

U.S. Department of Agriculture and the Washington Agricultural Experiment Station in

1960. It was selected by Harold W. Fogle at

the Irrigated Agriculture Research and Extension Center, Prosser, Wash., from tHe cross

'Bing' X 'Gil Peck' (131), 'Chinook' fruit

ripens 4 to 8 days earlier than that of 'Bing',

which it resembles in appearance. This earliness, offering the possibility of extending the

harvest season earlier when cherries are most

profitable, and the ability of 'Chinook' and

'Bing' to cross-pollinize each other, prompted

the introduction of 'Chinook' as an earlyshipping cultivar. The name was taken from

one of the mountain passes in the Cascade

mountain range in Washington.

'Chinook' fruit is large, heart-shaped to

rounded, and with a relatively large stylar
16 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

scar. The skin color is mahogany, remaining

glossy at maturity. The flesh is moderately

firm, medium to dark red, and uniformly

colored. The pit is medium sized and relatively

free from the flesh. Soluble solids are higher

than in *Bing', and titratable acidity is lower.

Trees of 'Chinook' are very vigorous,

upright-spreading, and productive. Blossoming is 1 or 2 days, and foliation 3 to 4 days,

earlier than 'Hing' in the Yakima Valley of

Washington. Petioles have a few fine hairs.

Tree hardiness is slightly better than that

of *Bing' but poorer than that of *Van'. 'Chinook' is adequately pollinized by *Bing', 'Van',

or 'Sam'. It processes satisfactorily. The fruit

is more subject to rain-cracking than is 'Bing'

fruit, is softer, and tends to abort heavily

when planted with 'Bing'. Hence the cultivar

has been rejected except in areas where its

earliness can be exploited by shipping before

'Bing' shipments from the area are ready,

'RAINIER' was also jointly introduced by

the U.S. Department of Agriculture and the

Washington Agricultural Experiment Station

in 1960. It was selected from progeny of 'Bing'

x 'Van' at the Irrigated Agriculture Research

and Extension Center, Prosser, Wash., in 1954

by Harold W. Fogle (131). 'Rainier' was

introduced because it combines the superior

bud and wood hardiness of 'Van' with large

fruit size in a light-fleshed cherry. The name

was derived from Mt, Rainier, a continuous!}

snow-capped mountain in the Cascade Range

in Washington, to connote the "white" flesh

of this cultivar.

The fruit ripens 3 to 7 days before 'Napoleon', is Van-shaped, firm, of high quality,

and attractive. The skin color is yellow with

considerable pink blush. The flesh is clear and

the juice colorless. The pit is relatively small

and free from the flesh. Pits from some trees

shatter, but the cause is not known. The condition has not occurred in experimental plantings in Washington State. Soluble solids are

equal to those of 'Bing', and titratable acidity

is lower.

Trees of 'Rainier' are vigorous, uprightspreading to spreading, very productive, and

precocious. Blossoming and foliation coincide

with those of 'Bing'. Winter hardiness appears

to be equivalent to that of 'Van'. Petioles are

glabrous. 'Rainier' is pollinized satisfactorily

by 'Bing', 'Van', or 'Sam'. 'Rainier' satisfactorily pollinizes 'Bing' and 'Chinook'. In experimental and commercial trials in Washington and New York, the cultivar appears well

adapted to brining and to canning. The fruit

has sufficient firmness for distant shipping.

'MOREAU' is the commercial synonym assigned in 1961 by the U.S. Plant Introduction

Station, Chico, Calif., to a dark-fleshed cultivar. Bigarreau Moreau (Bigarreau de St.

Charmez, Souvenir de Charmes, Bigarreau

Sandrin), introduced from Germany in 1937

(64^). The fruit ripens about a week before

that of "Black Tartarian'. It is round and

blocky and is larger and firmer than other

early sweet cherries. The flesh is semifreestone

and more acid than that of 'Black Tartarian'.

The tree is spreading in growth habit, becoming roundish when mature. Leaves are finely

serrate. Pollination tests in France showed

'Moreau' compatible with 'Napoleon', and preliminary tests in California indicate it is compatible with 'Bing'. Doubling of fruit apparently is much less common than in 'Bing'. The

fruit sometimes is irregular and soft-fleshed

under California conditions.

'EARLY BURLAT' is the commercial synonym assigned in 1961 by the U.S. Plant Introduction Station, Chico, Calif., to a darkfleshed cultivar from Europe, Bigarreau Hatif

de Burlat (Précoce de Burlat). The fruit ripens

2 days after 'Moreau' or almost 5 days before

'Black Tartarian'. Fruit is larger, smoother,

and firmer than that of the latter cultivar.

Although 'Early Burlat' fruit is less firm than

that of 'Bing', it is suitable for fairly distant

shipping. The flesh is fine textured and less

acid than that of most early cultivars. The

tree is moderately vigorous and upright to

upright-spreading. The leaves are coarsely serrate. Pollination tests in France showed 'Early

Burlat' compatible with 'Napoleon'. Frequency

of double fruit in 'Early Burlat' is lower than

in 'Bing'. The fruit is susceptible to raincracking.

'CORUM' is a light-fleshed cherry of unknown origin, found in 1945 on the farm of

Gordon Corum of Eugene, Oreg. It was tested
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 17

and introduced in 1961 by the Oregon Agricultural Experiment Station. *Corum' resembles

'Napoleon' closely but ripens its fruit 5 to 7

days earlier and is slightly soft-fleshed. It is

reported (15Í) to be well adapted to canning

and brining and to be about equal to 'Napoleon'

in hardiness and resistance to rain-cracking.

*Corum' satisfactorily pollinizes 'Napoleon',

'Bing', 'Lambert', 'Van', 'Sam', and 'Sue' in

Oregon tests. The fruit skin is pale yellow with

a pronounced red blush. The flesh is light yellow, and the juice is colorless. The pit is small

and clings slightly to the flesh. The fruit stem

is slender.

'MONA' was selected by Reid M. Brooks

from seedlings of the cross 'LaCima' x 'Chapman' planted in 1940. It was introduced in 1964

by the California Agricultural Experiment Station as a possible replacement for 'Black Tartarian' (11), The fruit is larger and firmer,

the tree is more spreading, and the bloom period coincides more closely with 'Bing' than

does that of 'Black Tartarian'. The fruit ripens

about a day later than 'Black Tartarian', and

the flavor is less tart. Although primarily

adapted to fresh-market handling, the fruit is

ccinsidered adapted to canning and brining.

The tree is vigorous, productive, and upright

t(> upright-spreading. Leaves are longer than

a\'erage. Petioles have a few fine, scattered

h lirs. Glands are mostly large, oval to reniform, and located at the distal end of the peticile. The cultivar is considered a satisfactory

p)llinizer for 'Bing', 'Van', *Starking Hardy

Giant', 'Moreau', 'Black Tartarian', and 'Chapman'.

'LARIAN' was selected by Reid M. Brooks

from the cross 'Lambert' x ('Bing' x 'Bush

Tartarian') and was introduced in 1964 by the

California Agricultural Experiment Station.

The dark-fleshed fruit ripens about II/2 weeks

before that of 'Bing' and is reported to be

larger, firmer, and better flavored than that of

'Black Tartarian' (11), The cultivar is relatively free of fruit doubles and apparently

more resistant to rain-cracking than 'Bing'.

The trees are moderately vigorous, upright

to upright-spreading, and moderately productive. Leaves are large and lanceolate, with

large dentations. Petioles are short and stocky

and have a few fine hairs. In California pollination tests, the cultivar blossoms with 'Bing'

and is compatible with 'Bing', 'Jubilee', and

'Bada'.

'JUBILEE' was selected by Reid M. Brooks

from the cross 'Lambert' x 'Napa Long Stem

Bing' and introduced in 1964 by the California

Agricultural Experiment Station (ii). In

California, fruit ripens about 6 days before

'Bing' and is larger than 'Bing'. The tree produces practically no doubles. Fruit, stem and

suture characteristics are similar to those of

'Bing'. The stylar scar, however, occurs at the

true apex, and the apex is pointed. The pedicel

flange attachment to the cavity is relatively

large. Flesh is red to dark red and is less tart

and less firm than that of 'Bing'. It has good

resistance to fruit doubling but is susceptible

to rain-cracking. It may be harvested over a

long period without excessive loss of quality.

Trees are productive, vigorous, and uprightspreading. Leaves are large and have long petioles with fine, scattered hairs. Glands are

relatively small, oval or reniform, or sometimes

lacking. Blossom season averages late but sufficiently overlaps 'Bing' and cultivars with similar blossom dates. In California tests, crosspollination by 'Bing', 'Lambert', 'Napoleon',

'Starking Hardy Giant,' 'Early Burlat', 'Moreau', 'Mona', and 'Larian' was adequate. Apparently the cultivar has a high chilling requirement.

'BERRYESSA' and 'BADA', two lightfleshed cultivars, were also selected by Reid

M. Brooks and were introduced in 1964 by the

California Agricultural Experiment Station

(11). Both w^ere introduced as possible replacement cultivars for 'Napoleon'. 'Berryessa', from

the cross of a seedling of unknown parentage

X 'Bush Tartarian', ripens about 6 days before

'Napoleon'. The fruit has medium to high

blush, a glossy cream-colored skin, and is larger

and firmer than that of 'Napoleon'. It is relatively free of doubles and rain-cracking. In

Oregon, 'Berryessa' does not pollinize 'Napoleon' satisfactorily.

The tree is precocious, productive, and vigorous. Leaves are large, oblanceolate, and have

long, mostly hairless, thick petioles. It blooms

with 'Napoleon' and cross-pollinizes with 'Na-
18 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

poleon', *Van', *Moreau', 'Starking Hardy

Giant', 'Mona', and other cultivars. It is suited

for canning and brining.

'BADA', from the cross of a seedling of unknown parentage x 'Ord', ripens about 4 days

before 'Napoleon' and poHinizes that cultivar.

The fruit has medium to high blush, glossy

cream-colored skin, and about the same size

and firmness as that of 'Napoleon'. It is highly

resistant to rain-cracking and free of doubles

in California tests. The stem cavity is deep.

The pedicel is longer and thicker than that of

'Napoleon'.

The tree is precocious, productive, moderately vigorous, and upright-spreading. Leaves

are obovate and medium-sized. Petioles tend to

be short, thin, and usually hairless. The cultivar blossoms between 'Lambert' and 'Jubilee'

seasons but usually sufficiently overlaps blossom ranges of 'Napoleon', 'Bing', 'Berryessa',

and 'Larian' and is pollinized adequately by

these cultivars. It is also suited for canning

and brining.

'ULSTER', which originated from the cross

'Schmidt' X 'Lambert' at New York State Agricultural Experiment Station, Geneva, N.Y.,

was selected in 1947 and introduced in 1964 as

a possible replacement for 'Schmidt' {133), It

has a more vigorous, more productive, and

longer-lived tree than does the 'Schmidt' cultivar. The fruit ripens just after 'Schmidt' and

is reported to be firm, large, very dark red, of

high quality, and resistant to rain-cracking

(133), Some resistance to cherry leaf spot

and superior blossom hardiness has been noted

in commercial test orchards. 'Ulster' crosspollinates effectively with all important cultivars in New York.

'HUDSON', also originated by the Geneva,

N.Y., station from the cross 'Oswego' x Giant',

was selected in 1935 and introduced in 1964

as a cultivar to extend the harvest season 10

days later than 'Lambert' {133), Trees are very

vigorous and rapid growing. The fruit is medium to large, firm to slightly tough when fully

ripe, darker than 'Windsor', and sweet. It tends

to hang well on the trees. The cultivar has some

resistance to brown rot. It effectively crosspollinizes with all important cultivars used in

New York except 'Giant', 'Rainier', and 'Yellow Glass'.

POLLINATION REQUIREMENTS

Provision for adequate pollination is a prime

requisite in sweet-cherry production. All known

cultivars except 'Stella' are almost completely

self-incompatible, that is, the pollen, although

normal in appearance and germinability, fails

to extend a pollen tube sufficiently to fertilize

ovaries of the same cultivar. Consequently, unless pollen is available from another cultivar

capable of fertilizing the main one, practically

no fruit sets.

In addition to being self-incompatible, some

groups of cultivars are cross-incompatible.

'Bing', 'Lambert', 'Napoleon', 'Star', and 'Emperor Francis' constitute the best known

group of cross-incompatible cultivars. Other

cross-incompatible groups include: (1) 'Governor Wood', 'Saylor' (Stark Gold), and 'Elton'; (2) 'Schmidt' and Teggy Rivers'; and

(3) 'Black Tartarian', 'Knight Early Black',

'Bedford Prolific', 'Black Eagle', and 'Early

Rivers'. None of the cultivars function as pollinizers for other cultivars in the same grouping. A cultivar from another pollinizing group

is needed to assure adequate fruit set. Incompatibility is reciprocally expressed; thus the

pollinizing cultivar will be pollinized satisfactorily by the main cultivar.

Many European cultivars have been classified

into pollination groups {26), Also these investigators have explained the nature of incompatibility in sweet cherries. As is true in

tobacco, incompatibility in cherries apparently

is controlled by an allelomorphic series of genes

designated as Si, S2, S3, and so on. Each plant

carries two of the allelomorphs. Pollen germinates, but pollen-tube growth is inhibited in the

style of a plant having the same incompatibility

factors, either from self-pollination or from

cross-pollination of two cultivars in the same

group. Hence the male gamete is prevented from

reaching the ovary in time to cause fertilization. If the pollen (S1S2 for example) has one
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 19

factor in common with the style (S1S3), the Si

pollen tube will be inhibited, but the S2 pollen

tube will penetrate the style normally. Thus

half of the possible combinations are fertile,

and adequate fruit set can result. If four different allelomorphs are involved (for example,

S1S2 pollen and S3S4 stylar constitution), all

possible combinations are fertile.

The John Innes Institute in England has released 3 self-fertile selections, which are being

used to breed self-fertile cultivars. 'Stella' is

the first such cultivar released. The selfcompatible selections are explained as trees

carrying an allelomorph (S4I), which nullifies

the inhibition of pollen-tube growth by the S4

alíele (66).

In the selection of a suitable cultivar for

pollination, the blossom dates of the two cultivars in question should overlap enough to ensure an abundant supply of pollen at the

time the blossoms are receptive. Canadian studies show that in the relatively unproductive

'Schmidt' variety, degeneration of egg cells occurs before blossoming to the extent that only

a few embryo sacs are functional when blossoming occurs (35, 36). The same phenomenon,

but to a lesser degree, exists in 'Bing', 'WindSOY\ and 'Hedelfingen', but most embryo sacs

ai'e still functional when the blossoms open.

Degeneration continues rapidly after the blossoms open. Hence, with these cultivars it is imperative that a source of pollen be available

continuously as the blossoms open. The safest

policy, therefore, is to use pollinizers which coincide in blossoming time with the main cultivar.

Apparently the reciprocal of any cross in

which the two cultivars are compatible will

also be compatible. Therefore, providing the

blossoming of the two cultivars overlap, a

known pollinizer can be planted with assurance it will be pollinized by the main cultivar.

In some cultivars, so-called "strains" are

known to exist, and these vary somewhat in

their ability to pollinize. In fact, strains of

'Black Tartarian' and other cultivars have been

shown to be in different pollination groups

(26), Care should be exercised, therefore, to

assure that the main and pollinizing cultivars

chosen for planting are from a true-to-variety

source and are proved pollinizers for each other

if either represents a variant strain.

Since the appearance of 'Van', 'Sam', 'Chinook', and other cultivars, it is now possible

to fill the orchard pollinizer positions with

profitable fruit-producing trees rather than

merely with pollen-producing trees.

PROPAGATION

Like most other fruits, sweet cherries do not

produce uniform seedlings. Therefore, vegetative propagation is used to propagate trees of

desired fruit and tree characteristics. Clones

can be indefinitely maintained by budding and

grafting, barring natural mutations or sports.

Nursery trees are produced by propagating

the desired scion cultivar onto a desired rootstock. Usually this involves budding a single

dormant bud onto a year-old seedling (liner)

just above ground level in July to September.

A bud formed in the axil of a leaf on currentyear wood is used. The T-cut, shield-bud

system (fig. 4) is usually used. Buds from previous season wood may be kept dormant by

refrigeration and June-budded on liners. Thus

nursery trees are 1-year-old scions on 3- or 2-

year-old roots, respectively, depending on

whether they were summer-budded or Junebudded. Bench-grafting dormant scions onto

liners or root pieces is possible but is laborious

and requires considerable proficiency.

A intermediate stem piece between the rootstock and scion sometimes is used to impart

greater trunk hardiness, to induce early fruiting, or to cause dwarfing of the scion cultivar.

This usually involves budding in 2 successive

years, but bench-grafting sometimes is used

to complete the propagation at one time.

In some instances, a shift in market demand

for a cultivar, disease-susceptibility, or other

economic factors may suggest changing cultivars. This can be done in young or bearing

trees by budding or grafting the top to a new

cultivar.
20 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

FIGURE 4.—Diagram of T-shield budding of sweet

cherries. A, The bud stick with shield-shaped buds

partly cut; B, T-shaped cut in the stock; C, bark

raised along side of the T-cut; Z>, bud inserted; Ef

placement of rubber band to prevent drying.

ROOTSTOCKS

Strong preferences have developed in different areas concerning the best rootstock for

sweet cherries. As a result of a 13-year test,

the St. Lucie cherry, Prunus mahaleb L., is

recommended in Utah as the best stock for the

arid climate and well-drained soils of that area

(25). In most eastern States and California,

wild sweet-cherry seedlings, commonly called

mazzards, have been preferred by growers because mahaleb roots are reputed to dwarf tree

size and reduce tree longevity {IH). In areas

where poor soil drainage is a problem, 'Stockton Morello' {P. cerasus) has adapted better

than mazzard or mahaleb roots.

Although growers generally prefer mazzard

rootstocks, nurserymen much prefer mahaleb

because of better seed germination and easier

budding over a longer period. As a result, nurserymen switched from almost exclusive use

of mazzard as a cherry rootstock before 1850

to increasing use of mahaleb for the last half

of the century and well into the present century. In certain areas, the advantages to the

grower of the mazzard or 'Stockton Morello'

rootstocks have outweighed the nursery advantages of mahaleb, and growers have demanded these rootstocks.

Gibberellins offer some hope for more dependable germination of mazzard seeds. Use

of gibberellins with sweet-cherry hybrids sub»

stituted for at least 3 months of the usual 5-

month after-ripening requirement and offered

the possibility of growing liners suitable for

budding a year earlier than possible without

its use {Jf2y Í5). Maximum germination was

combined with reduced rosetting, a condition

associated with insufficient chilling, when gibberrellin treatment followed 2 months of afterripening of the seed. Foliar sprays of gibberrellin were effective in forcing growth on

plants that rosetted.

In areas such as the Yakima Valley of Washington, cultivars on mahaleb rootstocks free of

disease produce trees of equivalent size and

longevity to those on mazzard roots. Several

factors could be involved. Day {29) noted that

trees on mahaleb rootstocks gave earlier hardening and better tolerance to low temperatures

in the early fall, more tolerance to zinc deficiency and an excess of lime, and better adaptability to sandy soils and dry conditions than

did trees on mazzard rootstocks. Under less

favorable conditions for mahaleb rootstocks,

the rootstock has a tendency to be overgrown

by the scion at the bud union, and to become

dwarfed and short-lived. The shallower root

system of mazzard rootstocks adapts better to

higher soil-moisture conditions and heavier

soils than do the deep roots of mahaleb rootstocks. Gophers often are more troublesome in

orchards on mahaleb rootstocks.

'Stockton Morello' rootstocks adapt better

to wet heavy soils than do mazzard or mahaleb rootstocks; also this stock may reduce tree

size in lighter soils. It is not a satisfactory

rootstock for 'Napoleon' in Oregon. 'Morello'

and other sour cherries give seedlings of variable size, so elimination of less vigorous seedlings in the nursery row is desirable.

Prunus fruticosa PalL, the European dwarf

ground cherry, has been used to a limited extent as a sweet-cherry stock. While the graft

unions appear compatible, the roots give poor

anchorage, and the understocks sucker profusely. True genetic dwarfs that occur from
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 21

sweet-cherry crosses have not yet been evaluated as rootstocks.

INTERSTOCKS

Above-ground trunk sections or complete

trunk and crotch portions of trees sometimes

are substituted for that portion of the scion

cultivar. These may be the same as the rootstock, or the stem piece may be different from

both the scion and rootstock. Early fruiting,

reduced tree size, and greater hardiness of the

trunk usually are the objectives sought. The

F12/1 mazzard rootstock from England, topworked out on the scaffolds, imparts bacterial

canker resistance.

Budding sweet-cherry trees high on the

trunk of P. mahaleb is effective in reducing

bacterial canker (29). Also topworking above

the crotches of mahaleb seedlings or substituting an interstock (trunk and crotches) of

an upright mahaleb type (Russian or Turkish

type) reduces infection by X-disease virus

(buckskin), permits detection and removal of

infected leaders and salvage of the tree, and

allows replanting in areas where infected trees

were removed (29 ).

Interstocks of P. cerasus, principally 'Montmorency' and 'Northstar', have been used to

control tree size of sweet-cherry trees. These

interstocks may be only a few inches of trunk

or may extend from ground level to 18 inches

out on main leaders. Because of the slower

growth rate of the sour-cherry section, both

the understock (usually mahaleb) and scion

usually overgrow the interstock (fig. 5). Growth

of nonbearing trees with 'Montmorency' or

'Stockton Morello' interstocks is not noticeably slower than that of standard trees, but

bearing starts a year or two earlier. Hence

the mature height of the trees is controlled

more easily because of greater spreading by

the weight of the first crop and reduction of

vegetative growth.

The trunk is one of the last parts of the

sweet-cherry tree to harden off in the fall. As

a result, trees that are relatively hardy in other

parts of the tree are vulnerable to injury from

early fall freezes in the trunk and crotch areas.

In areas where trees are subject to hard freezes

PN-3048

FIGURE 5.—Overgrowth of the interstock by the scion

variety. Such overgrowth is found where sweet cherry

is topworked high on mahaleb rootstocks or a

sour-cherry interstock is used. Note overgrowth

pointed out by the arrow.

before hardening is complete, substitution of

a hardier trunk may be desirable. Also where

"southwest injury" is common from sunlight

reflected onto the trunk from snow, a hardier

trunk section may be useful.

Trees using 'Northstar' (a dwarf P. cerasus

cultivar) interstocks appear to be smaller than

standard ones. Close plantings such as those

used for apple trees on 'Mailing VII' rootstock

may be possible. Slightly closer planting of

trees is possible with 'Montmorency' interstocks than with standard trees. Consideration should be given to the use of such trees

as fillers, because they will fruit before standard trees. Particular care should be used in

training to force wide-angled branches in trees

with 'Montmorency' crotches. Interstems of 6

to 12 inches of 'Montmorency' trunk give the
22 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

advantages of this stock but avoid the weak f

crotches.

TOPWORKING

Topworking trees of bearing age to a more

desirable cultivar allows the grower to change

his production to the new cultivar with a minimum of delay. Sometimes a grower is not sure

of the commercial potential of a new cultivar

and may wish to be growing trees of standard cultivars, which he may later topwork to

the new cultivar if it proves satisfactory. This

removes some of the time loss from indecision

on cultivars at planting time.

Trees that have been planted in the orchard

only a year or two may be budded at ground

level with a shield bud. However, even in young

trees it is desirable to salvage the trunk and

crotches unless the latter form narrow angles.

Usually it is desirable to bud or graft at least

18 inches out on main leaders.

The topworked leaders may tend to develop

as upright "poles" unless care is given to their

training (fig. 6). It is advisable to leave considerable brush in the center of the tree to encourage spreading of the topworked leaders.

Tying-down of the leaders in mid-May for

about a six-week period spreads the tree and

encourages earlier fruit set. Summer heading

likewise encourages wide-angled crotches.

PN-3049

FIGURE 6.—A vigorous sweet-cherry tree, topworked at

12 inches on mahaleb rootstock, showing good branching and early-fruiting tendencies. Note, however, a

tendency for the branches to develop into upright

"poles" (arrow) if not headed. Note also the intertwined sticks (upper portion) used to spread narrowangled limbs.

ORCHARD PLANTING

SITE

Site is of greater importance for sweet cherries than for most other fruits. Soil and climatic requirements are more exacting than for

most fruits. Since the trees usually blossom

during potentially frosty periods, higher elevations with good air drainage should be selected.

Soil should be reasonably well-drained and

should be deep enough to hold 4 inches of

available water or enough to supply a tree for

2 weeks during the high-water-use period. In

general the soil should be relatively light and

moderately productive. Excessive fertility may

cause "leggy" growth, delayed fruiting, and

greater susceptibility to winter injury or disease. The site should not be land recently used

for potatoes, tomatoes, melons, or other hosts

of Verticillium.

SELECTION OF NURSERY STOCK

Usually 1-year-old nursery trees are preferred for orchard planting. These are obtained

from single buds placed on rootstock liners in

July or August almost IV2 years before orchard

planting or in June of the year previous to

planting. In the former case, the buds remain

dormant the remainder of the first growing

season and, in either case, the bud forms the

nursery tree the summer previous to orchard

planting. The liner top is removed just above
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 23

the scion bud after the scion forces, and all

rootstock buds below the bud union are

stripped.

No difficulty is encountered in detecting

trees that failed to develop from scion buds

where mahaleb or ^Stockton Morello' rootstocks

are used. However, difficulty may be encountered in detecting bud failure when mazzard

stocks are used. Careful nursery practices

minimize this danger. It is well to become acquainted with nursery practices of the nurseryman from whom trees will be obtained. Nurserymen prefer to bud trees on a custom basis

and usually offer discounts for custom orders.

It helps them minimize the gamble of propagating cultivars for which there may be no

demand two years hence.

The grower should analyze his prospective

site in choosing the rootstock for his trees.

If the soil is light-textured and tends to be

droughty, he should consider the deeper root

system of mahaleb. Mahaleb should be considered also when the soil is alkaline, where some

replanting problems have been encountered, or

wliere the soil is known to be deficient in zinc.

In areas where early fall freezes are a known

hazard, or where X-disease infected trees

have been removed, mahaleb can be used for

itii earlier-hardening and disease-resisting tendencies.

On most eastern soils, except very- lighttextured and droughty ones, mazzard usually

is preferred. On the irrigated western soils,

wjiere none of the problems in the preceding

paragraph are serious, the grower has the option of fairly equivalent growth on either stock.

Where excessive moisture is a serious problem, 'Stockton Morello' understocks may be

used.

Cultivars to plant should be selected on current and projected demand of the marketing

outlets available to the area. If distant shipping is the chief outlet, and there are no immediate local market or processing outlets,

only the firm-freshed, large-fruited cultivars

should be considered for planting. If processing is the main outlet, productive, relatively

firm, freestone varieties are indicated. If brining is the sole outlet, productive, light-fleshed,

and relatively firm cultivars are preferred. For

local markets, the softer-fleshed cultivars may

be very acceptable.

Because of the rain-cracking susceptibility

of the firm-fleshed cultivars, the other desirable

characteristics of 'Bing' and similar cultivars

may be overbalanced in areas of considerable

rainfall during the late ripening and harvest

seasons.

The availability of pickers and the feasibility of mechanical harvesting should be considered also in selecting probable outlets and

cultivars.

Adequate pollinizers should be provided in

the initial planting to suffice for the early harvest years. Usually the number of pollinizers

needed is greater than in the mature orchards.

Pollinizers in every third permanent position in every third row are adequate for the

mature orchard. It is often advisable to provide additional pollinizers in filler positions

to ensure adequate pollination of the young

trees. The ratio of eight trees of the main cultivar to one pollinizer makes a convenient

planting.

Medium-sized trees, averaging 4 to 6 feet

high and more than %-inch caliper, are preferred for planting and usually give highest

survival. Smaller trees, except June-budded

ones, are often not thrifty and grow poorly.

Trees larger than %-inch caliper often give

poor survival.

Upon delivery, the trees should be placed in

underground storage with the roots covered by

shingle tow or peat moss, or they should be

heeled-in in a well-drained outside location,

with the trees slanted to the southwest to avoid

sunburning of the trunk and crotches. If the

trees dry out in shipment, soak them for several hours before heeling them in.

SOIL PREPARATION

The orchard site should be plowed or disked

in the fall or early spring, if needed, and thoroughly prepared before planting. If there is a

distinct plowpan, deep plowing may be advisable. A green-manure crop the year before

planting is desirable to improve soil tilth. Other

fertilization usually is not needed before planting.

If the orchard is to receive routine or sup-
24 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

plemental irrigation or underground heating

lines, such systems should be fully installed

before planting. These systems may dictate

tree-spacing patterns.

On slopes subject to erosion, or where sod

strips between rows are desired, row strips 5

to 6 feet wide may be plowed or rotovated,

preferably on the contour. The young trees

will not compete successfully with weeds and

grass. Therefore, these strips or circles around

each tree should be cultivated at least the first

3 years for optimum growth of the trees. Several kinds of rotary tree hoes are commercially

available for this purpose.

TIME OF PLANTING

Early spring, February to April, depending

on latitude and suitable weather, is the traditional time to plant trees. It is important to

be *êure the nursery stock has been stored

properly, protected from extreme cold, and

kept dormant until planting time. If these conditions are met, and the soil is moist or water

is added to the tree hole, excellent survival

should be expected.

Fall planting has the advantages of better

planting weather usually and of nursery trees

that are freshly dug and that have not had a

chance to dry out. The trees are dormant when

planted, and roots have time to become established before leaf buds break. In areas usually

subject to low winter temperatures, the grower

should avoid fall planting. In temperate areas,

as far north as New York, Michigan, and

Washington, fall planting is increasing.

as required, there will be no serious drop in

production. On the other hand, removal of

fillers left several years too long may cut the

crop in half for one or more years.

Where the square system is used, standard

permanent trees usually are set 20 x 20, 25 x

25, or 30 X 30 feet. If filler trees are used,

the initial spacing may be 10 x 10, 121/2 x

12^/2? or 15 X 15 feet, or the rows may be left

20, 25, or 30 feet apart with closer spacing

in the row. Assuming the former spacing system, two removals are necessary. First, alternate diagonal rows are pulled. This removes

half of the initial number of trees and gives

full-width row middles on the diagnoal. The

second removal is at right angles to the initial

planting and leaves one-fourth of the original

trees in a square arrangement (fig. 7, A). If

wider initial spacing is provided between rows,

only the final removal may be necessary. In

this case, a tree remains in the center of each

square.

II

p L P

1 i>

p P

p P

p

p

p

P^

P

P

P

P

P

P

P

P

P

P

P

P

P

P

P

P

P

P

P

P

P

P

P

P

P

P

P

P

III

P P P

P P P

P P P

TREE SPACING

A mature sweet-cherry tree with a favorable

regime will occupy 30 feet of space between

trees. However, 25 years may elapse before

the space is fully utilized. It is usually desirable

to plant filler trees. Despite the innate reluctance of most growers to remove trees when

they are bearing well, these filler trees must

be "fanned" (pruned more severely on one

axis) and removed as the permanent trees

gradually fill in the space. If fillers are removed

PsXps

^PsX

c P s^f >^ s

PSXPS P

P P

P

P P

P

P P

FIGURE 7.—Alternate planting systems: A, Square;

B, rectangular; and C, hexagonal; designs formed by

location of permanent (p) trees. /, Spacing of the

initial planting; //, spacing after removal of filler

(f) trees; ///, spacing after removal of semipermanent (s) trees. Lines show direction trees are removed.
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 25

An alternative spacing that gives more permanent trees to the acre is the rectangular pattern (fig. 7, B). An initial spacing of 24 feet

within rovv^s and 18 feet between rows may be

used. Pulling alternate rows removes half the

trees and gives 36-foot middles while permitting complete use of the space within the rows.

This system is generally used on hilly ground

or in contoured plantings where cross-travel

is impractical. Spacings of 30 x 22 or 15 x 22

feet are suggested in Oregon for orchards to

be mechanically harvested.

In the hexagonal system, initial spacings

are rectangles with a tree in the center (fig.

7, C). First removal (every third diagonal)

eliminates one-third of the trees. Second removal of alternate rows removes one-half of

the remaining trees. Either diagonal has wider

middles than the rows, and the permanent

planting becomes essentially squares or rectangles with a tree in the center. Performance

of orchard operations in any direction is possible under this system.

TRANSPLANTING

Losses during the first year after planting

are greater in cherries than in any other tree

fruit. Good care at the time the nursery trees

are received will help minimize losses. Soaking

trees that have become dry in shipment often

will salvage trees that otherwise would not

survive transplanting.

Holes should be dug wide and deep enough

to accommodate the roots in their normal position. Tractor boom diggers with 18- to 24~inch

augers are useful in digging holes. Unless water

is added at planting time, however, the hole

should be dug just before planting.

Any broken or injured roots should be

trimmed off before planting, and thin roots may

be shortened. Exposure of the roots to wind

and sun should be kept to a minimum to avoid

excessive drying out.

The trees should be set an inch or so below

their level in the nursery row. This places the

bud union at or just below ground level. If a

dwarfing or other special rootstock is used,

the union should be planted above ground. The

topsoil removed should be placed around the

roots and settled by moving the tree up and

down carefully as the first few shovels of soil

are added. Then the soil should be stamped

firmly. Where feasible, 2 or 3 gallons of water

should be added to give good contact of roots

and soil. The soil is firmed by stamping as the

hole is filled completely. Slight rounding of the

top will give a smooth surface for subsequent

cultivation.

TREE HEADING AND TRAINING

Unbranched average-sized nursery trees

should be headed at about 30 inches height

after planting (fig. 8). A second heading after

4 or 5 inches of growth occurs encourages

wide-angled branching. If the trees are weak

or winter-injured, heading lower than 30

inches may be desirable. Such trees should be

avoided if possible. Heading at 12 inches usual-

^:^A^i

FN-30B0

FIGURE 8.—A well-branched tree in July of the first

season after planting. The tree was headed at about

24 inches when planted.
26 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

ly forces a strong shoot with numerous wideangled branches.

Heading should be done in the spring to

avoid exposure of the cut surfaces to winterdamage. Whether the trees are planted in the

fall or spring, they should be headed before

the buds break dormancy.

Initial leaders may be selected on branched

nursery trees if they are well spaced and are

wide angled. The lowest leader should be about

18 inches above the ground and the others at

least 4 inches apart and distributed around

the tree. Usually three but not more than four

leaders are left. Heading should be at the same

height as for unbranched trees. If angles are

narrow and branches weak, all branches should

be removed and the tree handled as for an

unbranched tree.

CARE OF YOUNG TREES

Newly planted trees should receive extra

care until they are well established. Removal

of weed competition for nutrients and water

within the root area of the tree is essential.

Irrigation should be supplied as needed while

the tree is replacing roots lost in digging and

planting it. Control of insects and diseases

that may damage young trees during this critical period is important.

ORCHARD MANAGEMENT

CULTIVATION

The main objectives of cultivation are to

remove competition between the weeds and

trees for water and nutrients. Proper penetration of water and release of nutrients may be

improved, particularly in older orchards where

compaction of the soil by frequent use of

heavy equipment has greatly reduced the

water-penetration rate.

While the disk harrow is a time-honored

implement in fruit orchards, its use sometimes

causes more damage than benefit. Deep disking

cuts the feeding roots near the surface, often

defeating the purpose of cultivation. Where

shallow disking will destroy the weeds or

loosen the compacted zone, it is more advantageous to the trees than deep disking.

Where rainfall is sufficient to support a

cover crop, or where irrigation is available,

cultivation of only a 3-foot radius around each

tree prevents direct competition of the cover

crop with the trees and aids in preventing

erosion. Several rotary tree hoes suitable to

cultivation around individual trees or down

both sides of tree rows are available.

FERTILIZERS

Of the twelve essential nutrients, nitrogen

is the one most often found to be deficient.

In orchards with a good leguminous cover crop,

however, this element is almost always in adequate supply.

The other major fertilizer elements, phosphorus and potassium, are usually present in

adequate quantities in most soils. Calcium and

magnesium are not considered limiting to

cherry-tree growth in most areas.

Small quantities of several microelements

are also essential. Among these microelements,

manganese, copper, iron, sulfur, and molybdenum are not usually limiting under normal

conditions. Zinc and boron, however, may be

deficient, particularly in the neutral or alkaline soils of the irrigated regions, and marked

deficiency symptoms may appear.

As is true with other fruit trees, a balance

between the fertilizer elements is desirable.

Excessive applications of one element may induce deficiency symptoms of another element,

for example, too much potash may induce magnesium deficiency.

Where leaf analyses are feasible, this additional index of fertility status may be useful.

In general, soil analysis can be used only to

determine the general fertility conditions in

the orchard. Ultimately, adjusting fertilization

of individual trees to maintain good, but not

excessive, vigor is the most economical system.

Fertilization should be based on year-to-year

observations of growth, production, maturity,

quality, and deficiency symptoms of individual
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 27

trees. It is poor economy to add the major

elements in quantities in excess of the needs

of the trees and the cover. On the other hand,

annual applications of zinc to prevent the occurrence of deficiency symptoms may be more

economical than trying to correct symptoms

after they appear.

Nitrogen

Deficiency of nitrogen in cherry trees is

expressed by short, slender terminals ; by small,

pale-green to yellow leaves; and by small,

early-ripening fruit. These symptoms may also

be induced by natural or mechanical injuries

to roots or trunk, by girdling, by poor soil

drainage, or by drought. Although adequate

amounts of nitrogen may exist in the soil,

the conducting system of the injured plant

sometimes fails to deliver enough nitrogen to

satisfy the needs of the tree.

Excessive nitrogen delays fruit maturity

and retards fruit coloring. Applications of nitrogen should be reduced to trees pruned severely, to trees that lost fruit to low temperatures, or to those subject to ground water with

hi.^h nitrate content.

The best source of nitrogen fertilizer is the

one that costs the least per pound of actual

nitrogen applied to the ground. Cherry trees

appear to use nitrogen from various sources

equally well. Thus 6 pounds of nitrate of soda,

3 pounds of ammonium nitrate, 2.2 pounds of

urea, or 10 pounds of 10-10-10 fertilizer all

give about 1 pound of actual nitrogen. Each

of these nitrogen sources is very soluble and

penetrates to the tree roots quickly.

The amount of nitrogen to apply should be

based on the previous year's growth and production. A very general rule would be to apply

100 to 250 pounds of actual nitrogen per acre

per year.

An index of the fertility status of trees is

useful. Usually the amount of terminal growth

the previous season, allowing for the crop

borne, gives the grower an estimate of current

nitrogen needs. If vegetative growth is excessive, for example, over 18 inches on average

terminals, nitrogen application should be curtailed or even eliminated for a year. If terminal

growth is short, particularly when the crop is

light, nitrogen application should be increased.

Trees that are noticeably above or below average in vigor should receive less or more nitrogen than average trees.

The time of application may be late fall,

early spring, or a split application in both

seasons. Late spring or summer applications,

particularly of less soluble nitrogen forms, may

delay fruit maturity as well as possibly delaying tree hardening and increasing winterdamage susceptibility. Split applications may be

desirable where frosts often cause less than

full crops of fruit. The second application may

be reduced or eliminated, thus saving fertilizer and preventing excessive growth, in light

crop years.

The nitrogen fertilizer should be applied

evenly in a circle slightly larger than the periphery or '*drip line'' of the tree. If a cover

crop is growing in the orchard, a broadcast

application to satisfy the needs of the cover

should be superimposed on the tree applications.

In heavy cover crops, a concentrated circle

application may be necessary to get the nitrogen through the cover to the tree roots.

Use of barnyard manure as a nitrogen source

may induce or aggravate zinc deficiency symptoms in western orchards.

Excessive alkalinity may result from continued use of sodium and calcium nitrate fertilizers on irrigated western soils. Alkali deposits tend to accumulate at the soil surface,

sometimes encrusting it, as the water evaporates. As soil alkalinity increases, water penetration is greatly reduced, and plant growth

is retarded. Eventually only alkali-tolerant

plants will grow in the low areas where water

accumulates.

Excessive irrigation may alleviate the problem by flushing part of the alkali below the

root zone. Substitution of ammonium sulfate

or nitrate helps reduce the soil pH and stops

further alkali buildup.

On the other hand, continued use of ammonium sulfate or other acid-forming nitrogen

fertilizers may reduce the pH to a growthdepressing level. This can be particularly serious in eastern growing areas.

Proprietory *'leaf feeds" are available. These
28 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

may be used for rapid recovery from deficiency

symptoms where a short-time residual effect

of nitrogen is desired.

Phosphorus and Potash

Most soils provide ample phosphorus and

potash for sweet-cherry trees. The amounts

applied should therefore be about equal to those

removed annually by the trees.

In the irrigated Yakima Valley of Washington, ground application of phosphorus increased the P content of both leaves and fruits

but did not affect maturity or keeping quality

of fruits {117),

Potash response has been demonstrated in

sweet-cherry trees only in one western Oregon

orchard.

Minor Elements

Zinc deficiency in sweet cherries often is

called *'rosette" or '*little-leaf." Interveinal

chlorosis and shortened internodes during the

early flush of growth is an early symptom.

In severe cases, buds fail to grow at several

adjacent nodes, and the shoots that do grow

have small leaves, giving a tufted or rosetted

appearance.

Ground application of zinc fertilizers usually does not correct zinc-deficiency symptoms.

Late fall and/or dormant sprays of zinc sulfate

may correct incipient deficiencies. Severe deficiencies on alkaline soils usually require two

applications of zinc oxide spray (2 lb, per 100

gal. water), as leaves are expanding, to correct zinc-deficiency symptoms.

Boron deficiency occasionally may cause

leaf chlorosis between veins and necrosis of

leaf serrations. Magnesium deficiency occasionally causes marginal reddening and necrosis

of leaves. Chlorosis may occur from a low

availability of iron in alkaline soils or may be

induced by heavy applications of lime,

IRRIGATION

Irrigation is a necessity in most western

orchards. Commonly the systems are underthe-tree sprinklers, rills, or checks, often as

dictated by the terrain. Supplemental irrigation has proved beneficial also in area having

enough total rainfall but subject to periodic

droughts during the growing season.

Sweet-cherry trees are very susceptible to

"wet feet.'' Hence irrigation should be on a

demand basis rather than a calendar one. The

general tendency where ample water is available is to overirrigate. The need for irrigation

can be predicted reasonably well by following

an évapotranspiration chart for the area in

question {61). Likewise, moisture-tension

blocks can be monitored to determine the

approximate moisture at different soil depths

in specific orchards. Periodic checking of soil

samples in the upper 3 feet of soil will also

indicate the necessity for irrigation. If a ball

of soil taken from the 3-foot depth is moist

enough to resist crumbling when squeezed and

then jarred slightly, irrigation is not necessary.

On the other hand, cherry trees should not

be permitted to suffer from moisture stress.

Reduction in fruit size and tree growth may

result from temporary stress.

Over-the-tree sprinklers are used in some

western orchards. These systems are being

used experimentally in efforts to reduce heatinduced disorders, such as fruit doubles. The

rain-cracking and disease hazards might be

increased by these systems, which irrigate

when a predetermined temperature is reached.

No conclusive evidence of benefit or damage is

yet available.

COVER CROPS AND INTERCROPS

Conservation of the soil is an overriding

consideration in orchard management. Frost

protection often dictates use of land subject

to erosion. A permanent cover crop is the

ideal solution for sites where soil erosion may

occur. Competition for rainfall, however, may

prevent use of permanent cover crops.

While a good cover crop has real advantages

in a cherry orchard, provisions must be made

for the fertilizer and irrigation needs of both

the trees and the cover.

A clean-cultivated strip of about 3 feet on

either side of the trees should be maintained

at least 2 or 3 years after planting. Otherwise
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 29

tree growth is impeded by the competition for

water and nutrients. The shallow roots of the

cover may use most of the rainfall that would

sustain the trees under clean cultivation. Until

the trees have grown an extensive root system,

they are also at a disadvantage in picking up

nutrients.

Although intercropping of a young orchard

often is practiced to offset some of the planting

costs, it is not recommended. Interplanting

with potatoes, tomatoes, melons, and other

crops susceptible to Verticillium wilt, can introduce this disease to the orchard and result

in death of many young trees. There is

the additional danger of too much irrigating,

fertilizing, and cultivating of the orchard trees

in order to supply the demands of the intercrop. If an intercrop is used, it should be one

that will adapt to normal cultural practices

for the tree.

A good cover crop can be valuable in a mature cherry orchard for conserving the soil

and for maintaining the organic-matter content and water-infiltration properties of the

soil.

Legume covers supply at least part of the

nitrogen requirements of trees. However, caution is necessary with alfalfa cover because it

may cause delay in fruit ripening. Alfalfa also

provides ideal conditions for gophers and field

mice. Nevertheless, alfalfa is a good soil conditioner, and its deep root penetration tends to

break up hardpans. It also tends to prevent

or reduce zinc deficiencies. Shallow-rooted

legumes, such as sub-clover {Trifolium subterraneum L.) are preferable.

Nonlegumes usually are preferred, because

it is then easier to regulate the nitrogen

regime for the trees. Root systems are shallower and ofi'er less competition for nutrients.

The fescues generally have proved best adapted

to orchard cover. Of the fescues, creeping red

(fig. 9) is very satisfactory. Orchardgrass and

Kentucky bluegrass are also satisfactory.

Merion bluegrass is satisfactory in most respects, but it is subject to severe rusting in the

fall. Native or weed covers often are very satisfactory. Since the vegetation in such covers

usually grows taller than creeping red fescue

or similar grasses, it is necessary to mow the

PN-3051

FIGURE 9.—Creeping red fescue cover crop in a young

sweet-cherry orchard.

cover to permit normal orchard operations and

to prevent seeding of noxious weeds.

Rotary mowers are well adapted to most

orchard covers. A pressure-sensitive attachment to the rotary mower can be used to trim

closely around trees while the mower moves

forward.

WEED CONTROL ''

Weeds compete with trees for moisture and

nutrients. Elimination of this competition is essential during the first 3 or 4 years. Control

of deep-rooted and noxious weeds is desirable

in older orchards.

Weeds harbor insects, diseases, nematodes,

and rodents. Therefore a systematic weedcontrol program should be incorporated into

the general production program. In mature

oi'chards this may consist merely of mowing

or disking the ground cover at stages that will

prevent seeding of noxious weeds. Usually,

however, mechanical or chemical means of

eliminating weeds must be employed.

Many annual broadleaved weeds and weedgrasses invade orchards. Smàrtweed (Polygonum spp.), pigweed {Amaranthus spp.),

lambsquarters {Chenopodium album L.),

" This section was prepared principally by L. L.

Danielson, chairman, Agricultural Environmental Quality Institute, Northeastern Region, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Md.
30 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OP AGRICULTURE

goosegrass (Eleusine indica. (L.) Gaertn.),

and several others are particularly bothersome.

In addition, many perennial species such as

poison ivy (Rhus radicals L.), deciduous tree

seedlings, v^^ild blackberry {Rubus spp.),

quackgrass {Agropyron repens (L) Beauv.),

Johnsongrass (Sorghum halepense (L.) Pers.),

and Bermudagrass (Cynodon dectylon (L.)

Pers.) are serious pests.

The methods and materials selected for use

in a weed-control program depend on the cultural practices used in the specific production

areas. In general, however, a combination of

mechanical and chemical control practices is

most successful. Some chemicals must be used

differently under irrigated and nonirrigated

conditions and under different cultivation

methods. Follow local recommendations in

combining methods.

Mechanical Devices

Rotary tree hoes are available, which will

cultivate a strip around the trees or down each

side of the tree row if the orchard is ditched

for irrigation. These hoes are side-mounted

so the tractor operator can easily see the area

he is cultivating and can minimize tree damage. One type has a revolving drum with spike

teeth on the side-mounted shaft (fig. 10, A).

Optional rotovator blades aid in cultivation as

well as preventing accumulation of debris on

the drum, and an optional wheel regulates depth

of hoeing. For maneuvering the hoe in and

out where cultivating in the row only is possible, a hydraulic-cylinder section may be added

to the shaft. This type is best adapted to soils

relatively free of rocks, but blade and spike

edges may be hard-faced with suitable alloy

weldings.

A second type of tree hoe has spikes in a

floating head (fig. 10, B), which rotates right

or left to cultivate towards, or away from, the

tree. This type adapts particularly to uneven

terrain and rocky ground.

No additional hand hoeing is necessary with

either type of hoe if the operator is skilled.

The row middles are maintained by periodic

mowing, giving a firm turf for heavy sprayers

PN-3052 PN-3063

FIGURE 10.—-Tractor-mounted rotary tree hoes: A,

Drum-type with optional rotovator blades and depthcontrolling wheel; B, floating-head type with the shaft

lifted into road position.

and other equipment. Favorable nesting-places

for mice are disrupted by tree hoeing.

Chemical Methods

Cultivated weed-free areas under established

trees can be easily maintained by applying simazine [2-chloro-4,6-bis(ethylamino)-

s-triazine] or dichlobenil [2,6-dichlorobenzonitrile] herbicide as a soil treatment before

weeds emerge. Simazine is applied in early

spring, using a carefully directed coarse spray

that does not touch the trunks, exposed roots,

or foliage. Dichlobenil is applied in spray or

granular form after harvest, allowing 12

months between treatment and the next harvest.

Contact herbicides such as dinoseb [2-sec-
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 31

butyl-4,4,6-dinitrophenol] and paraquat [1,-

1' dimethyl-4'-bipyridinium salt], which destroy the foliage and stems of plants, are used

to kill annual broadleaved weeds and weedgrasses in the early stages of growth. They

are also effective in controlling topgrowth of

perennial weeds, if additional applications are

made when new growth appears. Dinoseb is

usually fortified with fuel oil, diesel fuel, or

Stoddard solvent, and treatments are made

during crop dormancy. Thus, late winter or

early spring applications destroy most establislied winter weeds and give some preemergence control of spring-germinating weeds.

Dinoseb should not be used during the growing season. Paraquat is a relatively new, highly

effective contact herbicide. Early spring treatments are made to destroy emerged annual

weeds and the tops of perennial weeds while

trees are still dormant. Treatments are repeated

as weeds continue to emerge during the growing season.

Each of these herbicides should be applied

as localized, or shielded treatments, that prevent the herbicide from reaching the fruits,

foliage, and trunks of the trees. Livestock

should not be pastured in the treated areas.

Specific information on optimum herbicide

rates and times of treatments should be obtained from local experiment station personnel because of the many factors such as climate,

soil composition, moisture, and cultural practices that affect the safe and effective use of

herbicides. The manufacturer's label on the

herbicide package should be studied and all

precautions carefully observed.

PRUNING AND THINNING ^^

PRUNING

Pruning of sweet-cherry trees, as is true of

other fruit species, delays bearing. This delay

is objectionable and to be avoided as much as

possible. However, some pruning is necessary

to maintain the selected leaders, to prevent

crossing and rubbing of competing branches

ar d to keep the tree within a reasonable height.

Of the numerous objectives of pruning cherry

trees, keeping the tree low deserves special attention. If trees are allowed to go unpruned

during the early years, very '*leggy'' framework branches result (fig. 6). In some trees,

the first lateral on the bottom scaffold branch

originates 6 or more feet above the base of the

scaffold. This height adds very materially to

the ultimate height of the tree.

Selecting leaders is the main thing to be

accomplished in pruning the first 2 or 3 years

(fig. 11, A). Narrow crotches are decidedly objectionable, particularly when sour-cherry interstocks are used. If necessary, it is advisable

to take a second, and rarely a third, year to

complete leader selection. Future crowding

and pinching of limbs can be avoided by spac-

^- This section was prepared by J. C. Snyder, deceased,

formerly Extension horticulture specialist, Washington

S:ate University, Pullman, Wash.

ing the leaders over a 2-foot trunk section (fig.

11, B). Selected leaders should be kept dominant over other branches. However, shortened

interscaffold branches may help to keep the

crotch angles wide and produce good early

fruiting wood. Pinching young terminals during the growing season and heading during

the dormant season (fig. 12) are both effective

methods for producing low trees. The purpose

of either method is to force lateral branches

relatively low on the scaffold branches.

Pinching

Branching about 14 to 18 inches from the

base of the scaffold is desirable. After the

shoots are about 18 to 20 inches long, 3 or 4

inches at the tip may be pinched out. Because

all branches are not at the pinching stage at

one time, it is usually necessary to go over the

orchard two or three times the first growing

season. Some orchardists pinch once the second season also (fig. 13).

Pinching is practiced more on trees that are,

headed conventionally than on those headed

severely. Severely headed trees usually produce a flush of shoots. Because these shoots

often produce 3 or more feet of terminal

growth, pinching on them should induce good

branching. Since pinching removes very little
32 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

-ii:<

I B ••yf..

PN-S064 PNFIGURB 11.—A, A 2-year-old tree in which the strong shoot was headed severely the first winter. Note the numerous branches available for selection, and the wide-angled crotches. B, After pruning, four longer leaders are

designated as main leaders, and several shorter branches are left for early fruitwood.

wood, it delays bearing only slightly. This

slight retardation in early fruiting is a distinct advantage pinching has over dormant

heading.

The effectiveness of pinching varies. It

nearly always forces branching, but sometimes

the resulting branches are sharp-angled. This

condition seems to be more serious when

only the tip, rather than several inches of the

shoot, is pinched out. The main objective of

pinching is a flush of branches below the point

of pinching. These can be organized into a desirable framework later, provided, of course,

that some attention is given to selecting permanent framework branches from the beginning.

Heading

There is a tendency to be cautious about

heading young cherry trees in northern regions. Trees of the more popular cultivars are

susceptible to winter-damage, particularly during the early years. Pruning almost inevitably intensified this susceptibility. There is a

widespread feeling that cherry trees should not

be pruned. Notwithstanding these reasons for

caution, heading, during the training years at

least, has some significant advantages. It is

not imperative, however, because artificial

spreading of the branches can produce an early

bearing and low tree (fig. 14, B). Spreading of

this kind requires considerable time for tying,

but it gets the tree into bearing earlier.

The purpose of heading is to keep the framework branches from producing long sections

without any side branches. The end result is

a low, spreading tree. The severity of heading

depends on the length of the terminal growth

and how far beyond the last whorl of branches

you want the next one. Ordinarily, laterals on a
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 33

main branch should not be closer than about 18

inches. This means that branches that have

not grown more than 18 inches may not need

heading. To be sure a branch produces laterals,

it is well to clip the terminal. Some branches

longer than 18 inches may not need heading.

In general the upright main branches are the

ones that need heading (fig. 15). If these are

not headed, the tree will become too high.

Most horizontal and nearly horizontal branches

need not be headed.

Heading should start with the first dormant

pruning and continue for five or six years or

until the framework is well established. As the

tree gets older, the percentage of branches to

be headed decreases. Also, as the tree gets older,

some branches may be shortened to less than

18 inches. Eventually some thinning is necessary to allow the tree to develop the proper

shape. More thinning is necessary following

intensive pinching or dormant heading.

Artificial Spreading of Branches on

Young Trees

Pruning induces vegetative growth and delays bearing. Because of this fact, there is a

tendency to prune the minimum necessary.

For this reason mechanical spreading to make

trees low has advantages over pruning. Even

at greater cost and inconvenience, artificial

spreading can be very profitable.

There are almost unlimited techniques and

devices for spreading narrow-crotched and upright branches of a young tree. Notched boards

and forked sticks are common. These, however,

sometimes fall out, particularly in windy areas.

A short piece of 1" by 1" board with a finish1

'^\r-rir-t.;:

.X. AV *

A--V)>- %l

c

'*?*

PN-3056 PN-3057

FIGURE 12.—A, A tree that received no pinching during the first growing season. Note the initial heading height

(marked by the arrow) and the long terminal growth (about 5 feet) of the three branches. B, All branches

were headed, but the uppermost one was left longer than the other two. The lowest limb was spread to prevent a

narrow angle.
34 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

PN-3058 PN-3059

FIGURE 13.—A, A 2-year-old tree that was pinched twice the first growing season and once the second season.

There was no further pruning. Framework branches have been spread with notched laths. B, A 5-year-old tree

that was pinched during the first and second growing seasons with very little dormant pruning. Thinning out of

excess branches will be necessary as the tree gets into full production.

ing nail in each end makes a good spreader.

For very small branches, wire braces are effective and easy to use. For large branches,

the wire must be stiff, but for most branches

during the first season, telephone-type wire is

satisfactory. When using braces, attention

should be given to removing them near the end

of the growing season or earlier. Tying the

branches to stakes is a dependable but inconvenient technique (figs. 16 and 17). Tying

branches down to an angle of 45 degrees is

ideal. Stakes driven in early May can be removed by July.

Girdling

Girdling or ringing of sweet-cherry tree

trunks is -not recommended because of the danger of breakage, the overgrowth (fig. 18) that

will result in the girdled area, and gumming

which often occurs in a wounded area. However, girdling or ringing of a temporary leader

is an effective method of inducing early fruiting. Removing a %(;" ring of bark from 3-yearold sweet-cherry hybrids in May near the base

of a main leader (%" caliper or less) and covering the wound with grafting tape to prevent

drying, induced large clusters of fruit in many

instances the following year i-íO). Girdling of

larger wood was less effective, presumably because the phloem tissues were replaced too

quickly to increase fruit-bud initiation.

Concentric or spiral ringing with a knife is

less drastic but can be effective. A continuous

spiral ring twice or three times around a leader

may induce fruit setting with less danger of

breakage.
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 35

Timing of girdling or ringing is critical. In

Washington State, girdling in early May (past

full bloom but before much leaf growth) was

most effective. Leaves on the girdled branches

became yellowish-green, but they returned to

normal green as the girdles healed. Accumulation of carbohydrates above the girdle overbalances the vegetative tendencies of the young

tree, and some fruit buds, rather than all vegetative buds, are initiated.

Chemical Control of Tree Size

Trees have been dwarfed experimentally

with succinic acid, 2,2-dimethyl hydrazide

(SADH) 1^'^^ U), The material is now cleared

for commercial use, but at rates and timings

that do not retard growth. Under experimental

conditions, the material will retard terminal

growth, shorten internodes, and hasten coloring of fruit {iy 91), Further research may reveal chemical growth-retardant treatments

that are compatible with regulations on residue and fruit quality. Possible benefits from

use of this growth retardant are reduction of

pi'uning and harvesting costs; control of tree

size, thus avoiding crowding by filler trees and

p(îrmitting mechanical harvesting; and spreading of fruit maturity. Labor could be used

more efficiently by successive treatment of segments of orchards predominantly of one cultivar.

Pruning the Bearing Tree

During the training period, a tree develops

both tree structure and fruiting wood. By

about the fifth year the tree should produce up

to 50 pounds of cherries, and by the tenth year

there should be an abundance of fruiting wood

throughout the tree. Up to this point, no effort

has been needed to maintain fruit size or to

renew fruiting wood. The pruning has con-

" Applied as Alar 85, manufactured by Uniroyal

Chem., Fresno, Calif.

^^ Trade names are used in this publication solely for

the purpose of providing 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 not mentioned.

sisted mainly of heading vigorous upright

branches and, rarely, thinning out temporary

branches that crowd permanent branches (fig.

19).

As the tree gets into heavy production, attention must be given to renewing fruiting

wood. While the tree is young, slight heading,

mainly to side branches, forces good fruiting

wood. Most severe heading is necessary in older

trees with spurs several inches long. In very

old trees it may be necessary to prune out considerable 1- to 3-inch wood. As is true with

other tree fruits, pendant and horizontal wood

is least vigorous and should be the first wood

pruned. In very heavy bearing trees, pruning

may give all the fruit thinning necessary (fig.

20). Likewise this type of pruning helps to

maintain a good supply of new fruiting wood

distributed evenly over the entire tree. In general, removal of fairly large branches, but occasionally some detailed cutting, including

some heading of heavily fruiting small

branches, is required.

THINNING FRUIT

Little information is available concerning

methods of thinning cherry fruits. A higher

percentage of the blossoms can be permitted to

set fruit than in other Prunus species. However, some thinning to increase individual fruit

size can give returns far outweighing the possible loss in total tonnage. Considerable care

is necessary to prevent thinning beyond the

point that will give appreciable fruit size increases (fig. 21).

Hand thinning methods, although effective,

are usually too time-consuming to be economical. Some detailed pruning in mature trees will

help reduce the number of fruit buds and

thereby reduce the eventual fruit set. Restricting the number of pollinizer trees in orchards

of productive cultivars will reduce set. Likewise restricting the time hives of honeybees

are left in the orchard to a minimum of favorable pollinating weather will reduce set, providing native bees and other pollinating insects

are not numerous. The latter practice would

not be advisable on cultivars such as 'Schmidt',

which has shy-bearing tendencies.
36 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

^.'" ' '»í\"--ííivP?^'^^^

PN-3060 PN-3061

FIGURE 14.—A, A 5-year-old tree headed and thinned each year from time of planting; B, one developed by

spreading with very little pruning.

Sweet cherries have been thinned experimentally with chemical sprays. However, results have been variable, and no compound is

registered for this use.

Selective pruning of the dormant tree accomplishes a large part of the thinning operation and at present is the only practical

method.

PROTECTION AGAINST BIRDS

Annual destruction of sweet-cherry fruit by

birds is substantial. In large plantings, the

damage may not be noticeable in individual

trees. In small plantings or in backyard trees,

a high percentage of the fruit may be destroyed

or damaged by birds. Provisions for protection

against bird damage should be considered, even

though not adopted as a standard management

practice.

In areas where large flocks of starlings occur, this bird may destroy large quantities of

cherries. Blackbirds, while often numerous in

cherry orchards, usually are not so destructive

of fruits as are robins, several of the ñnches,

sparrows, crows, ravens, and magpies. Near

large bodies of water, sea gulls may be very

destructive.

Several methods have been devised for protection of ripening fruits from bird damage.

Most of these have limited and temporary value

or are almost prohibitive in cost. Control can

be obtained by screening the trees with various types of netting, including used fish nets.

Very recently, nylon and other plastic screens

with Y¿-mch and larger meshes have become

available. An individual tree may be protected
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 37

by a cloth thrown over the tree or supported

on a frame. Blocks of trees are protected in

some foreign regions by nets supported on pole

frames similar to those used to support hops.

Several less effective but less expensive devices may give temporary protection against

bird damage or reduce the damage. Various

carbide, acetylene, or liquid propane gas cannons, which can be regulated by the rate that

water is dripped into the carbide or that gas

is released into the chamber, are available.

These give control for a few days, until birds

become accustomed to the regularity of the

explosions. Strings of firecrackers spaced on a

continuous rope fuse to fire at irregular intervals can be exploded in the trees. Metallic

or paper streamers, such as those used by

service stations; strings of whirling devices;

or strings of objects that will produce noises

in the wind may give limited protection. Any

noise-making or distracting device will give

some temporary protection. Recordings of distress calls sometimes are effective in repelling

starlings.

Repellent sprays have not appeared feasible

because of undesirable residues and residuetolerance restrictions.

Reduction of the population of noxious birds

in the orchard by trapping has been appreciable in western orchards. Plans for a starling

trap have been developed by Fish and Wildlife Service personnel for use near Pacific

Northwest orchards and cattle feedlots (38).

Consult your agricultural extension agent for

local recommendations.

PN-3062

FIGURE 15.—Wide-angled, well-spaced branches from

heading leaders (at arrows).

INSECTS AND MITES ^^

Sweet cherries may be attacked by a variety

of insects and mites, the most important of

which are the cherry fruit flies, Rhagoletis

cingulata cingulata (Loew), R. cingulata indifferens Curran, and R. fausta (Osten

Sacken); the black cherry aphid, Myzus cerasi (Fabricius); the pear slug, Caliroa cerasi

(L.); the San Jose scale, Aspidiotus perniciOSÎIS Comstock; the plum curculio, Conotrachelus nenuphar (Herbst); the European red

mite, Panonychus ulmi (Koch); the mcdaniel

" This section was prepared by Howard Baker,

formerly assistant chief, Entomology Research Division,

Agricultural Research Service, Beltsville, Md. Retired.

mite, Tetranychus mcdanieli McGregor; the

two-spotted spider mite, T. urticae (Koch);

the plum nursery mite, Aculu^ fockeui (Nalepa); certain lepidopterous larvae, as the

pandemis moth, Pandemis albaniana Walker,

fruit tree leaf roller, Archips argyrospilus

(Walker), and mineóla moth, Mineóla acitulella Hülst; and the shot-hole borer, Scolytus

rugulosus (Ratzeburg).

Insecticides are commonly depended on to

prevent insect and mite damage to cherries.

Recommendations for the control of these pests

in the home orchard are given in Home and

Garden Bulletin 190, entitled "Insects on Decid-
38 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

PN-3063 PN-3064

FIGURE 16.—A combination of heading and tying down branches to maintain wide-angled branches in a vigorous

2-year-old tree : A, Before pruning ; B, after pruning.

uous Fruits and Tree Nuts in the Home

Orchard." Copies may be obtained from the

Superintendent of Documents, U.S. Government

Printing Office, Washington, D.C. 20402. Similar information is published by the experiment

stations or extension services of the various

important cherry-producing States.

CHERRY FRUIT FLIES

In the northern and northwestern States,

sweet cherries are sometimes infested by the

larvae or maggots of fruit flies. Two native

species are involved; the cherry fruit fly, R.

cingulata subspecies cingulata in the East and

subspecies indiffevens in the West (6, i7), and

the black cherry fruit fly, R. fausta, which occurs in both areas. Adults of cingulata strains

are about two-thirds the size of the house fly,

and those of fausta are slightly larger. These

species have yellowish heads and legs but are

distinguished by conspicious bands across the

wings (fig. 22) and differences in the coloration of their abdomens; the abdomen of cingulata is marked by a series of distinct white

crossbands, and that of fausta is entirely black.

These species commonly occur together, fausta

appearing about a week in advance of cingulata strains and usually in smaller numbers.

Otherwise, they have similar seasonal histories

and habits.

Injury is caused by the larvae, which tunnel

through the cherry to the pit and destroy the

flesh. Infested fruit appears normal until the

larvae are almost fully grown, when sunken

spots appear on the cherries. Later, affected

fruit may shrivel on one side, the flesh may decay, and small emergence holes may appear in

the skin. Injury is generally greater in latethan early-season cultivars and still greater in
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 39

PN-3065

FIGURE 17.—A 5-year-old tree in which spreading by

tying to ground stakes has been substituted for all

but correctional pruning. Note the abundance of fruiting wood.

late-maturing fruits left on the trees after

fruit-fly sprays are discontinued. Cherries

grown for processing must be maintained free

of fruit-fly infestation; any degree of infestation may result in condemnation of the entire

crop by processors.

The cherry fruit flies overwinter as pupae at

a depth of 1 to 3 inches in the soil. Adults begin

to emerge late in May or early in June and

continue to emerge for 3 to 5 or 6 weeks, depending on the area and season. After a preoviposition period of from 7 to 12 days, the

flies deposit eggs singly in slits just through

the skin of preferably ripening cherries. The

eggs hatch in 5 to 8 days. In Washington State

( Í7), an oviposition period of 36 days at 90°

F. and longer periods at lower temperatures

was reported. During that time females deposited on the average of 386 eggs each at

90°, 99 at 65°, and 17 at 60°. Frick also found

the flies to be very sensitive to extremes of

temperature; at 55° they laid no eggs, and at

100° all the flies in cages died within 5 days.

The dirty white, legless larvae become fully

grown (about i/4,-inch long) after feeding in

the cherries about 2 weeks, after which they

leave the fruit, drop to the ground, and enter

the soil to pupate. In most areas there is a

single generation, with about 10 months of the

year being spent in the pupal stage in the

soil. In Washington (47), a small second brood

was reported, and in Montana (37), it was

reported some specimens require 2 years to

complete the life cycle.

Control consists of poisoning the adults durPN-3066

FIGURE 18.—Typical girdled leader (left) and ungirdled one (right) of a sweet-cherry seedling. Numerous

fruits were induced on the girdled leader of this

4-year-old seedling girdled the previous May. A few

fruits also were produced on the ungirdled limb

(right). Ungirdled seedlings of this age rarely produce fruit.
40 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

PN-3067 PN-3068

FIGURE 19.—A semihorizontal young bearing cherry branch: A, Before pruning and B, after pruning. Note the

vigorous terminal growth (about 10 inches) and the 2-year-oId wood, which has numerous fruit spurs. Some of

the heavy 2-year-old wood is removed to encourage development of new wood and to thin fruit buds.

ing the 7- to 12-day interval between emergence and egg-laying, with two to four spray

applications at intervals from the time the first

adults are reported to the beginning of harvest.

Information on adult emergence can usually

be obtained from County extension agents; if

not, it can be obtained by seeding the ground

with wormy cherries in the summer and placing a cage over the seeded area the following

spring or by suspending one or two simple

traps on cherry-tree limbs 6 to 8 feet above

ground just before the time early cultivars of

cherries begin to show color. A simple, effective

trap consists of a Vs-inch tempered composition

or plywood board, 6x8 inches, painted with

yellow enamel, coated with a sticky adhesive

that retains its tackiness, and suspended over

a small jar about half filled with lumps of ammonium carbonate. Examine the traps at 3-

day intervals, and replenish the bait as needed.

The presence of cherry fruit flies can be determined by comparing the wing markings of flies

emerging in the cages or captured on the sticky

boards (fig. 23) with those in fig. 22.

BLACK CHERRY APHID

The black cherry aphid is the fairly large

black, shiny aphid that curls the tender foliage

of sweet-cherry trees (fig. 24) in the spring

and early summer throughout the cherrygrowing areas of the United States, often severely checking the growth. Infested trees and

fruit are often covered with a sticky honeydew

in which a sooty mold may develop.

This aphid passes the winter in the egg stage,

the eggs being placed among or near buds and

in crevices, leaf scars, and other places oifering protection on twigs and small branches.

Hatching of eggs usually begins about the time
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 41

PN-3069 PN-3070

FIGURE 20.—A mature bearing limb: A, Before pruning and B, after pruning. Terminal growth ranges

from none to several inches. Pruning consisted of

heading fairly large wood and thinning out some spurs.

cherry buds swell and is generally complete by

the time the buds open. The young aphids

promptly migrate to the buds to feed, where

they become adult females in about a month

and then produce living young. Several generations follow until, in midsummer, winged

forms are produced that leave the cherry

trees for alternate hosts not completely known.

A later generation returns to the cherry trees

in the fall and produces a wingless generation

that lays the overwintering eggs.

Control is most effective when the trees are

sprayed while they are completely dormant to

destroy the overwintering eggs. If the early

sprays fail to give adequate control, the trees

should be sprayed again in the spring and

summer when the aphids appear. For best results, applications should be made before many

leaves are curled.

MITES

Mites are tiny, eight-legged sucking pests,

closely related to insects (fig. 25). They cause

major damage to the foliage of sweet-cherry

and other orchard trees throughout the United

States. Four species occur most commonly on

PN-3071 PN-3072

FIGURE 21.—A, A branch with excessive fruit set in

some places. Such heavily loaded branches are difficult to pick and may reduce fruit set the following

year. B, A branch on which the load is well distributed.

The stems are exposed for easy picking, but the fruit

load is adequate.
42 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

B

The European red mite overwinters as small

red eggs on the twigs and branches of deciduous tree fruits, principally around rough

areas on the twigs on the underside of

branches. Hatching of the over-wintering eggs

begins about the time apple buds show pink.

The tiny nymphs and subsequent adults, which

are barely visible without magnification, are

characterized by their red color and stiif,

whitish, curved spines on their backs. During

the summer most of the eggs are laid on the

leaves. This mite may develop from egg to

adult in 2 to 3 weeks or less under the most

favorable conditions and in a month or more

when cool temperatures prevail. Hot, dry

weather accelerates development and favors a

rapid increase to outbreak numbers. There may

be from 4 or 5 to 10 or 12 generations a year,

depending on the area and season.

The two-spotted spider mite overwinters as

an adult orange-colored female, protected by

leaves and trash on the ground or, to a limited

PN-3073 PN-3074

FIGURE 22.—Wing patterns of cherry fruit flies. A,

Ciierry fruit ñy; B, blaclt cherry fruit fly.

sweet cherries—the European red mite and

two-spotted spider mite throughout the sweetcherry growing areas of the United States, the

plum nursery mite (92) throughout northern

cherry-growing areas, and the mcdaniel mite

(78, 80) in the Pacific Northwest. The nymphs

and adults suck out the contents of the leaf

cells, including the chlorophyll, causing the

leaves to become bronzed or brown and dry.

The plum nursery mite cuts up the leaves and

causes them to have a dry or russeted appearance. When injury is extensive, many of the

leaves drop prematurely, and the size and quality of the fruit may be reduced. On sweetcherries, except with the plum nursery mite,

serious injury does not usually occur until after

harvest and occurs less commonly than on most

other deciduous tree fruits. With the plum nursery mite, injury most commonly occurs just

before or during harvest, depending on the

weather.

|F*/A

4 * ^

'4

V

.^

Jj.

Ä'

#

v

PN-3075

FIGURE 23.—Cherry fruit flies on sticky board trap.

'->W:í A~'.~M¡.i^ --
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 43

PN-3076 PN-3097

FIGURE 24.—Cherry foliage injured by the black cherry

aphid: A, Before leaves are curled; B, after leaves

are curled.

extent, under bark scales on the trees. The

overwintering females become active with the

advent of warm weather in the spring and

begin feeding on the foliage in the lower, interior portion of the trees and on weeds and

grasses in the orchard. When the orchard

ground cover becomes unsuitable as food, the

mites migrate to the trees. As the season advances or infestation increases, the mites

spread upward and outward over the entire

tree if permitted to develop unhindered. The

mites are usually greenish or yellowish when

feeding, often with two dark spots showing

through the body. The eggs, which are nearly

colorless, are laid on the underside of the leaves,

especially along the veins and midrib. The

mites develop from egg to adult in a week to

ten days under the most favorable conditions,

but may require as long as a month or more,

depending on the season. There are several generations each year. Toward the end of summer, when the mites become crowded or cool

temperatures occur, many of the adults cease

PN-3078 PN-3079

FIGURE 2$.—A, Two-spotted spider mite; B, European

red mite.
44 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OP AGRICULTURE

feeding, and the females become reddish to

orange and migrate to their hibernation quarters.

The mcdaniel mite is similar to the twospotted spider mite in general appearance,

habits, and seasonal history.

The plum nursery mite overwinters in clusters as an adult female, chiefly in cavities of

dead or shrunken buds and to some extent in

crevices in twigs and bark. This mite emerges

from its overwintering quarters when buds

are expanding and soon scatters over the new

foliage, primarily to the underside of the

leaves. Injury is characterized by curling and

dwarfing of foliage and by a brown or bronze,

scurfy condition of the lower epidermis. The

adult mites are minute vermiform creatures,

which are pale to brownish yellow. They are

invisible on the foliage, the larvae being whitish and somewhat translucent. A generation

may be completed in 6 days in warm weather,

and there may be as many as 15 generations

each season. In most seasons the population

reaches its maximum during July, but activity

may continue until low temperatures prevail,

as long as succulent foliage remains (92).

Since mites are less likely to reach outbreak

proportions on cherries than on most other

deciduous tree fruits, a suppressive-type spray

program after harvest is usually adequate, but

it is sometimes necessary to apply control

measures before harvest. When mites appear

on the leaves, two applications, 7 to 10 days

apart, of an effective mitleide are usually adequate for control.

PEAR SLUG

The appearance of skeletonized leaves on

cherry trees indicates the occurrence of the

pear slug (80), often referred to as the cherry

slug when it occurs on cherries. Damage is

due to the feeding of the slimy appearing,

sluglike, olive-green to almost black larvae that

skeletonize the leaves by eating the upper

surface (fig. 26). The full-grown larvae are

about one-half inch long. When abundant they

may cause sufficient injury to, and loss of, foliage to interfere with the growth of the fruit

and development of fruit buds. This insect.

FIGURE 26.—Pear slug and its injury.

PN-3080

originally from Europe, occurs throughout the

cherry-growing areas of the United States.

This insect overwinters in the pupal stage at

a depth of 2 or 3 inches in the soil. Adults

appear late in the spring, in May or in June,

according to locality and seasonal conditions.

They are 4-winged black and yellow sawflies,

a little larger than the house fly. The female

sawflies cut slits in the upper surface of the

leaves, in which the eggs are laid. The eggs

hatch in one or two weeks, after which the

young slugs feed almost exclusively on the

upper surface of- the leaves. Two to three

weeks are required for them to become fullgrown, after which they drop to the ground

and form cells in the soil. Within these they

pupate and transform to adults in about two

weeks. A second brood of slugs appears in
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 45

the trees in August. These slugs, when fully

grown, drop to the ground and enter the soil

to form a cocoon in which they pupate and

pass the winter.

The pear slug is easily controlled by spraying the trees when the young slugs are first

observed on the foliage.

PLUM CURCULIO

The appearance of crescent-shaped scars

(fig. 27) on the fruit soon after it sets and

for 2 to 3 weeks thereafter indicates attack

by the plum curculio. Damage is due to the

feeding and egg-laying punctures of the adult

curculios in the cherries and to the destruction of the flesh of thé cherries by the feeding

of the developing larvae. Damaged fruit is

scarred, misshapen, and worthless. This native

insect attacks cherries in all areas in which

they are grown east of the Rocky Mountains.

It is also an important pest of apples, peaches,

and cultivated and wild plums. Unlike most

other host fruits, the injured cherry does not

drop, but may hang and mature. Thus, larvae

may be present in harvested fruit, constituting

a serious problem for the fresh-fruit and processing market.

This curculio overwinters as an adult in

protected places, such as afforded by leaves

and trash in and around the orchards. The

adults are about 14 inch long, hump-backed,

brownish snout beetles mottled with gray (fig.

28). They become active in the spring shortly

after peach trees begin to bloom or a little

later. They feed on the leaves and blooms

until fruit is present. Feeding and egg-laying

in the fruit begins soon after the fruit sets

and starts to grow. The eggs are laid in

crescent-shaped cuts. Under laboratory conditions each female may lay an average of

several hundred eggs, but under natural conditions the number is much less, at times

less than 100. Eggs hatch in about a week,

and the yellowish-white, legless grubs feed

in the flesh of the fruit for about 2 weeks

or slightly longer. The full-grown grubs (fig.

29), which range from 14 to 1/2 inch in length,

leave the fruit and enter the soil to a depth

of 1 to 3 inches. There, they pupate and develop

into adult beetles in 3 to 4 weeks. In a few

days the adults leave the soil and may feed

on available hosts until they hibernate in the

fall. There is but one generation a year in the

important sweet-cherry growing areas, but

PN-3081

FIGURE 27.—Curculio egg and feeding punctures in

the cherry. FIGURE 28.—Plum curculio adult on peach.
46 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

PN-3083

FIGURE 29.—Plum curculio larva in cherry.

in a zone in the latitude of Delaware to Virginia there may be a partial second generation, and farther south there may be two

generations.

Control can be obtained by spraying the

trees two or three times at 8- to 10-day

intervals, beginning at petal fall or shuck

split, with an effective insecticide.

SAN JOSE SCALE

The occurrence of roughened bark with a

grayish appearance and weakened and dead

twigs and limbs and small reddish spots often

occurring at points of attack indicate the presence of the San Jose scale (fig. 30). This

introduced insect now occurs throughout the

United States. Injury is due to the sucking

of the juices from the twigs and branches,

which gradually weakens the aifected parts.

If left undisturbed, this insect may cause the

death of the infested trees with its feeding.

The insect overwinters most successfully as

a half-grown nymph beneath a protective

scale covering, although all stages are present

in the fall. Growth is resumed shortly before

bloom. In sweet-cherry growing areas, the

scale becomes full-grown and starts giving

birth to living young in June. The covering

of the full-grown female is nearly circular,

about the size of a pinhead and grayish, with

a darker central nipple-like projection; that

of the male is somewhat smaller and elongated, with the nipple at one end.

Underneath, the scales covering the mature

females are yellow. Each female produces 200

to 300 young or crawlers, which move about

for a short time. Then they settle on the

bark, leaves, or fruit and secrete a covering,

beneath which the insect remains the rest of

its life. The covering is enlarged as the insect

develops. There are commonly two to six annual generations, depending on the length of

the growing season.

Scale insects usually are best controlled by

spraying infested trees during the dormant

or delayed dormant periods. If necessary, they

can also be controlled by sprays applied later

in the growing season when the crawlers are

active.

SHOT-HOLE BORER

Conspicuous, small holes in a scattered pattern (fig. 31) over the trunk and branches

of a sweet-cherry tree indicate infestation by

one of the shot-hole borers, most commonly

Scolytus rugulosus (Ratzeburg). The adult is

a small, dark-brown or black beetle, cylindrical in shape, and about Vio inch long. This

borer prefers trees in a weakened condition,

which may occur from neglect, lack of moisture, winter injury, disease, other insects, or

from mechanical damage. Injury to such

trees is caused by the larvae and adults feeding in the sapwood, forming centipedelike figures in the wood. When the insect is abundant,

it may attack healthy trees, boring into the
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 47

PN-3084 PN-308B

FIGURE 30.—San Jose scale: A, Bark encrusted with scale; B, scales magnified.

twit just beneath or into the base of a bud

or fruit spur that is weakened or killed.

The beetles first appear from April to June,

acco iing to the latitude. The female gnaws

a hold about i4o inch in diameter through the

bark and a slightly larger burrow in the sapwood about parallel with the grain of the

wood, mining out small niches into which

the eggs are deposited. The eggs hatch within

a few days into small footless larvae that

burrow and feed in the sapwood for 30 to

36 days. Soon thereafter, they become adult

beetles and gnaw their way out through the

bark. A few days after the adult females

emerge, they begin depositing eggs for a

second brood of larvae, which will feed in

the trees during the latter part of the season.

In the more northern area of infestation, the

second-brood larvae spend the winter in the

trees, becoming adult early the following

spring. Farther south, the larvae become

adults before winter and deposit eggs, which

hatch to provide a third brood of larvae.

To discourage attacks of this insect, maintain trees in a healthy vigorous condition and

destroy weak and dying trees. Remove infested branches and broken or weak ones that

might become infested, and destroy them

promptly. An insecticide spray applied when

adults are active sometimes will prevent damage. Whitewash trunks to prevent sunburn,

especially high-headed trees.

LEPIDOPTEROUS LARVAE

Damage to the buds and foliage of cherries

early in the growing season, particularly in

the Pacific Northwest, is generally caused by

one or more species of lepidopterous larvae,

such as the fruit tree leaf roller, pandemis

moth, and Mineóla moth {80).

The fruit tree roller overwinters in the &%%
48 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

B

PN-3086 PN-3087

FIGURE 31.—Shot-hole borer: A, Exit holes in apple branch; B, gum exuding from points of injury on cherry.

stage (fig. 32) in masses of 100 or more eggs

on the limbs, twigs, and trunks of trees of

most deciduous tree fruits, including cherry.

The eggs hatch about the time the buds begin

to open. The small green caterpillars with

black heads feed on the unfolding leaves, webbing them together. They eat large irregular

holes in both fruit (fig. 33) and foliage until

they become full grown in June. They then

pupate in the rolled-up leaves and emerge as

moths 10 to 12 days later (fig. 34). These

moths lay the overwintering eggs in June and

July.

The pandemis moth overwinters as a small

light yellow-green larva in trash or in a web

constructed on a tree trunk at the surface

of the ground. These larvae crawl up the trees

in the spring as soon as leaves are out, and

feed on the foliage. They become full grown

in May and spin loose cocoons in the leaves.

Moths appear late in May or in June and

deposit eggs in clusters of 90 to 150 on the

upper surface of the leaves (fig. 35). These

hatch in about 2 weeks. The small larvae feed

on the tender foliage at the tips of branches

or along the midrib of leaves. Later they feed

on fruit, on cherries most commonly about

the stem end. The second brood matures in

July or August, and the moths are active in

August and September. The young larvae from
SWE"ET CHERRIES: PRODUCTION, MARKETING, PROCESSING 49

their eggs feed on the foliage until cold

weather forces them into hibernation.

The Mineóla moth overwinters as partlygrown brown larvae in hibernacula placed in

the smaller crotches or in crevices in the bark

on the trees. They leave the hibernacula in the

spring and bore into the buds, destroying

many blossoms. They become full grown in

2 to 4 weeks, then they drop to the ground

and form cocoons, within which they pupate.

The moths emerge from these cocoons in July

and lay eggs singly on the lower surface of

the leaves. The pinkish larvae hatching from

these eggs burrow into the fruit and, if abundant, may cause considerable damage. This

brood of worms becomes full grown late in

July or early in August and produces a second

brood of moths. Larvae hatching from eggs

laid by these moths feed on maturing fruit

or foliage, then spin silken cocoons in which

they hibernate.

These species and the eye-spotted bud moth

(Spilonota ocellana (Denis and Schiifermuller)), which also attacks the opening buds,

can be controlled by spraying or dusting with

an insecticide just before the buds open. If

the pandemis moth is present, a second application should be made at petal fall.

PN-3088

FIGURE 32.—Egg mass of fruit tree leaf roller.

FUNGAL AND BACTERIAL DISEASES

Fungus-, bacterium-, and virus-incited diseases cause the loss of approximately onequarter of the potential cherry crop ; estimates

on the sweet-cherry portion are not available.

Bacterial diseases and fungus-caused root and

trunk rots may kill trees and thereby remove

part of the orchard from production until

new trees are bearing. Some organisms kill

buds and blossoms before fruits are initiated,

and others attack the developing fruits or

indirectly reduce the yield by impairing the

leaf surface that supplies nutrients to the

fruit (2). Even after the crop is mature and

harvested, diseases originating in the orchard

continues to take their toll of the harvested

fruit.^"'^ The costs, in time, effort, and money,

" This section was prepared by H. R. Cameron,

Oregon State University, Corvallis, Oreg. Assistance on

the brown rot disease by J. Ogawa, University of

California, Davis, is gratefully acknowledged.

of controlling or living with diseases must be

considered in determining the feasibility of

establishing new orchards.

Sweet cherries are damaged by several fungus diseases, most important of which are:

Brown rot, Monilinia laxa (Aderh. and Ruhl)

Honey or M. fructicola (Wint.) Honey; armillaria root rot, Armillaria mellea (Vahl ex Fr.)

Kummer; verticillium wilt, Verticillium alboatrum Reinke and Berth. ; collar rot, Phytophthora cactorum (Lebert and Gohn)

Schroet., or P syringae (Kleb.) Kleb, and

Poria ambigua Bres. ; cherry leaf spot, Coccomyces hiemalis Higgins; coryneum blight,

""" These diseases are described and some are illustrated in color in U.S. Dept. Agr. Handb. No. 414,

"Market Diseases of Stone Fruits: Cherries . . .," issued

December 1972. Copies available from Superintendent

of Documents, U.S. Government Printing Office, Washington, D.C. 20402. 65 cents.
50 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

PN-3089

FIGURE 33.—Cherries injured by feeding of fruit tree leaf roller.

Coryneum beyerinckii Oud. ; black knot, Dibotryon morbosum (Schw.) Theiss. and Snyd. ;

witch's broom (cherry leaf curl) Taphrina

cerasi (Fckl.) Sadeb. ; powdery mildew, Podosphaera oxyacanthae [DC] deBary; perennial canker, usually caused by Valsa leucostoma [Pers.] Fr.

BROWN ROT

Brown rot is the major fungus disease, because it can severely damage blossoms,

shoots, leaves, and fruit {US). In areas where

spring rainfall is high, blossom infection is

the most serious. It occurs early in the season,

and subsequent infection of other parts of the

tree result from conidia (asexual spores) that

develop on, and are disseminated from, infected blossoms. In areas that receive summer

rains or use sprinkler irrigation, fruit infection may be more serious than blossom infection {85).

Cherry blossoms may be infected at any

time from bud swelling to petal fall, but

are most susceptible after full bloom. The

amount of infection depends on the temperature, moisture, and amount of inoculum present. About 6 days after infection, singlecelled spores (conidia) develop on the affected

blossoms and are released in large numbers.

These infect other blossoms, and in wet climates, young leaves and green fruit. Since

spores are continually released from infected

parts of the tree throughout the growing season, new infections may be initiated whenever

conditions for infection are favorable.

PN-3090

FIGURE 34.—Adult of fruit tree leaf roller, and pupal

skin protruding from leaf cocoon.
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 51

PN-3091

FIGURE 35.—Egg mass of pandemis moth.

shoots produce abundant conidia, which infect

the blossoms during the following spring.

Blossom symptoms start as water-soaked

areas on the white petals (fig. 36). These

areas turn light brown and are sometimes

mistaken for normal senescence, or freeze

damage. In moist weather the infected areas

soon become covered with gray or tan pustules

of spores, which infect other blossoms. The

fungus may grow from infected blossoms into

the attached shoot or leaves. Infections on

shoots eventually form cankers, which may

girdle and kill the entire shoot. Infections on

leaves most frequently are associated with

damage from hail or wind, or with direct

contact with other diseased tissue. Sympitoms

consist of an expanding dark-brown watersoaked area.

Fruits become more susceptible as they

ripen, and symptoms develop rapidly. Infected

areas are dark brown and soft, and they may

extend to the pit. Production of gray or tan

spores usually follows a few days after infection. Because of the extreme susceptibility

of the ripe fruit and the rapid growth of the

fungus, brown rot may be a serious problem

during harvesting, processing, and shipping.

Control measures are necessary at all of

the various stages of the disease. For many

years control measures were limited to proThe brown-rot fungus can penetrate fruit

directly, but more frequently it enters through

wounds or cracks. Mature fruit of most sweetcherry cultivars cracks when wet, providing

an ideal infection point for the spore from

infected blossoms and twigs. Once infection

is established and the amount of inoculum

builds up rapidly, control may become very

difficult.

Infected fruits that remain on the tree

shrink and dry into structures known as

"mummies." In the spring mummies on the

ground may produce apothecia (cup-shaped

fruiting bodies) in which sexual spores are

formed and shot into the air. Apothecia are

rarely seen in the orchard and are not an

important source of spores that infect blossoms. The mummies that remain on the tree,

and the cankers that develop on infected

PN-3092

FIGURE 36.—Brown-rot blossom blight of sweet cherry.
52 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

tection of the ripening fruit. Numerous sprays

or dusts were applied just before and during

harvest. These methods have been fairly satisfactory, but they leave chemical residues on

the fruit. With the use of the newer organic

chemicals, the residue problem has increased,

and efforts are now being made to control

the disease at an earlier stage. In most areas,

protectant sprays are recommended against

blossom infection. Preventing infection early

in the season increases fruit set and greatly

reduces the amount of inoculum available to

infect the mature fruit.

Although brown rot can greatly reduce the

marketable crop, satisfactory control can be

obtained by carefully following recommended

control measures (78). Current recommendations on the control of brown rot should be

obtained from the Extension Service of your

State agricultural university.

linger into the second season. Frequently,

surrounding trees show symptoms the year

after the first tree dies. Trees adjacent to

infected trees usually are already infected and

should be included in attempted control measures.

The disease is identified by the presence

of characteristic white fan-shaped fungus

mats, which develop between the wood and

the bark in rotting roots (ñg. 37). Brown

shoestringlike rhizomorphs often develop on

the surface of roots and may extend into the

surrounding soil. These can be mistaken

for small roots, but they are darker and are

composed of many strands of fungus. Goldenbrown mushrooms sometimes develop around

the base of the dead or dying tree.

Once the fungus has become established,

it is very difficult to eliminate from soil. Soil

fumigation with carbon disulfide has been

ARMILLARIA ROOT ROT

Armillaria root rot is a very serious disease

of fruit trees in localized areas. The causal

fungus, once established, lives as a saprophyte

on organic matter in the soil but can infect

and invade roots of living plants with which

it comes in contact. Infected trees usually are

killed, and replants are subject to the same

hazard. The areas of infection can usually

be associated with previous orchards or with

cleared deciduous-forest sites. Armillaria isolates from evergreen forests do not seem to

be pathogenic on fruit trees.

The fungus attacks and follows roots,

spreading from tree to tree at the point where

roots from adjacent trees intermingle. Infected roots have been known to maintain

the fungus in the soil for more than 15 years.

Roots of new trees planted where old trees

were removed eventually come into contact

with old infected roots, and the disease reappears.

Tree symptoms are typical of diseases

caused by root pathogens that girdle the trunk

and main root system. Leaves are smaller than

usual, pale green in color, and curled. Eventually they wilt. Affected trees usually die the

first year after symptoms appear but may

FIGURE 37.—Armillaria root rot at base of sweet-cherry

trunk.
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 53

satisfactory on light sandy soils in California,

but on heavier soils it has not been possible

to get the fumigant deep enough into the

soil to penetrate infected pieces of root. Fumigation treatments with more effective chemicals are expensive and have not been completely satisfactory.

VERTICILLIUM WILT

Verticillium vi^ilt has caused serious damage

in sweet-cherry orchards planted on infested

sites. The fungus enters through wounds in

roots or rootlets; then it grows through the

woody cylinder up into the trunk and scaffold

limbs. Initial external tree symptoms are small

leaves and poor terminal growth. During hot

weather, when transpiration is high, leaves

on the infected parts of the tree may wilt and

die. Usually only one or two major limbs are

affected at a time. In subsequent seasons the

disease may show up in other parts of the

tree or may not appear again (115). Internal

symptoms consist of dark-brown discolored

areas in the wood of the trunk and scaffold

limbs and irregularly scattered brown flecks

in the smaller wood. Isolation of the fungus

from the wood frequently is difficult during

the summer months. Topworking of infected

trees frequently results in a lower percentage

of successful unions than normal. No satisfactory measures are available for treating

infected trees; sites that have a past history

of verticillium wilt should be avoided. A few

clones of mahaleb cherry are somewhat tolerant and may come into use as resistant rootstocks.

tree. Phytophthora species are classed as

water molds. They produce zoospores (swimming spores), which are easily moved from

tree to tree by flowing water. Infected areas

in the orchard tend to be more irregular

than those of Armillaria. Single infected trees

may occur randomly through the orchard.

The first symptoms are failure of foliage

to develop normally in the spring, wilting,

and finally collapse of the tree. The bark and

wood tissues in the upper part of the tree

appear healthy, but infected tissue can be

found near the ground line. In trees infected

by Phytophthora, the advancing margin of

the infection appears irregular and consists

of thin bands of brown, reddish browh, and/or

greenish brown tissue (fig. 38). The infection

may move as high as 3 feet above soil level,

but is generally only in tissues below the

ground level. Poria infection is associated

with a white fungus that produces pale yellow fruiting structures. Top symptoms are

seldom noticed until the fungus has girdled

the tree and it is too late for control measures.

Chemical control measures have not been very

satisfactory. The best control for Phytophthora is to reduce the amount of time that

the soil near the trunk is saturated with

water. This may mean improving the drainage

or changing methods of irrigation.

CHERRY LEAF SPOT

For many years cherry leaf spot has been

a serious disease of sour cherry, but has not

COLLAR ROT OR CROWN ROT

Collar rot is caused by one of several species of Phytophthora and by Poria {31). In

most areas tree losses due to this disease are

small. Poor drainage, overirrigation, or heavy

rains, which cause waterlogging of the soil,

favor the Phytophthora organism. Losses due

to Poria may be associated with well-drained

soils. The causal fungi infect roots and may

kill a band of bark on the lower trunk below

the ground level, resulting in girdling of the

.1 2 :î I : e 7 8 ") 10I1I2KII

PN-3094

FIGURE 38.—Phytophthora canker from inoculation of

scaffold limb.
54 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

been of commercial importance on sv/eet

cherry except on nursery trees. During the

past 5 years the incidence of leaf spot in

sweet-cherry orchards has increased rapidly.

The cultivar 'Republican', commonly used as

a pollinizer, has been particularly susceptible.

Serious infections have also been observed on

other commercial cultivars.

The causal fungus enters the leaf through

the stomates when moisture is available for

spores to germinate. The first infection of

new leaves is from spores released from the

dead leaves on the ground. These spores are

carried to the lower branches of the tree by

air currents and windblown rain. The spread

up through the tree may be quite rapid, depending on the temperature and the frequency

of summer rains. Foliage loss may eventually

be from 5 to 90 percent. In severe cases the

tree may leaf out again and the new foliage

also become infected. In addition to crop reduction, severely infected trees frequently go into

dormancy with insufficient food reserves and

are therefore much more susceptible to winter

injury.

Leaf spot infections are first noticed as

small purple areas on the upper surface of

green leaves (fig. 39). On the lower surface

directly below the purple area there is a small

white spot. The white area has a sharp margin in contrast to the rather diffuse margins

PN-3095

FIGURE 39.—Cherry leaf spot on sweet-cherry leaves.

The leaf on the right shows the white spore masses

on the lower surface.

of the purple area. Numerous infections may

occur on one leaf, which causes it to turn

yellow and drop off. Infection also may occur

on the fruit pedicel causing a girdling of

the pedicel and a subsequent fruit drop. Fruit

infection may occur but is seldom serious.

Spray injury or viruses may also cause leaf

fall, but these can be distinguished from

leaf spot by the absence of white spore masses

in the spots.

Chemical control measures in sweet-cherry

orchards for this disease usually have not

been recommended. In some areas, such as

Western Oregon, summer sprays are suggested

to reduce defoliation in severely infected orchards. The number of sprays necessary for

control depends on the amount of infection

and the frequency of summer rains.

CORYNEUM BLIGHT

Coryneum blight is seldom of commercial

importance in sweet-cherry orchards. Symptoms on the fruit consist of small pale spots

with a red margin. The spots may coalesce

to form irregular shapes. Early infection results in failure of the fruit to size evenly. In

western United States the disease is seldom

sufficiently serious on sweet cherries to warrant application of chemical sprays.

WITCH'S BROOM

Witch's broom, or leaf curl, of sweet cherry

is sporadic in occurrence and not usually of

commercial importance. In early spring the

infected leaves are red to rose-colored, somewhat thick and curled (fig. 40). Shoots growing from infected buds are thick, twisted and

bushy, giving a broomlike appearance. The

disease is easily controlled by removing and

destroying the infected witch's brooms.

BLACK KNOT

Black knot is seldom observed on sweet

cherry and is normally controlled by removing

the infected limb. The disease may be recognized by the irregular black swellings on the

infected limbs.
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 55

PN-3096

FIGURE 40.—Leaves from a limb infected with witch's

broom. The leaf on the right is healthy.

POWDERY MILDEW

Powdery mildew is very common on the

leaves of sweet-cherry trees, but it seldom

causes serious damage except on young nursery

trees. It develops as white patches of fungus

scattered over the leaf surface (fig. 41). In

severe cases it may cause defoliation or stunting of the infected shoots. Mildew may also

infect the fruit, causing a brown leathery area

on the skin, and may under favorable conditions cause serious losses. Control measures

are usually not necessary, but sprays or dusts

may be applied if the local situation warrants.

PERENNIAL CANKER

Perennial canker, often referred to as Valsa

or Cytospora canker, has not been a serious

disease of sweet cherry where good pruning

practices have been used. Where infection has

occurred, it has been through wounds caused

by breakage or improper cultural practices

(32). With the proposed use of shakers to

harvest the fruit mechanically, the number of

wounds may increase. The bark at the point

where the shaker grasps the limb can be broken

by the jarring action of the shaker. These

wounds serve as points of entry for both

saprophytic and parasitic organisms.

BACTERIAL CANKER

Bacterial canker and crown gall are the only

two significant bacterium-incited diseases of

sweet cherry. These diseases are caused by

Pseudomonas syringae van Hall and Agrobacterium tumefaciens (Smith and Townsend)

Conn, respectively. However, both may cause

serious damage to trees and eventually loss in

production.

Bacterial canker is characterized by varioussized, usually sunken lesions on the trunk and

smaller limbs of the trees, some of which exude

copious amounts of gum (IJpS). The canker

characterized by gum exudation is the best

known and most easily recognized. These usually develop at the base of an infected spur

and then enlarge up and down the trunk. Extension of the canker is usually much more

rapid above the point of infection than below,

and spread to either side is relatively slow, resulting in a long, narrow canker.

Cankers usually develop during fall and winter but are first noticed in late winter and

early spring. Infected areas are slightly sunken

and may have a slightly darker brown color

than the rest of the bark. When the cankered

area is cut, the bark may be any shade from

bright orange to brown. The cambium may

or may not be affected. At both the lower and

upper margins of the canker, narrow brown

streaks extend into the normal tissue. As the

trees break dormancy in the spring, gum will

be formed by the surrounding tissue and may

exert enough pressure to break through the

bark and run down the outside of the limb.

Cankers that do not produce gum are similar

FIGURE 41.—Powdery mildew on young sweet-cherry

leaves.
56 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

in appearance but are usually more moist and

sunken, and may have a sour odor. Cherry

trees may exude gum from wounds other than

those caused by bacterial canker. Wounds resulting from winter injury and mechanical

damage may be confused with bacterial canker

symptoms.

The first symptoms of bacterial canker infection on cherry leaves are dark-green, angular or circular, water-soaked spots about 1 to

2 mm. in diameter (27). The spots frequentl:y

are surrounded by a yellow halo. As the leaves

mature, the water-soaked area becomes brown

and eventually the infected area becomes dry

and brittle. If these areas fall out, the leaves

take on a shot-holed or tattered appearance.

In severe cases the entire leaf tip and margin

may drop off.

Infected areas on fruit are flat, irregular

in shape, dark brown to black, and range from

2 to 3 mm. in diameter. Some spots are depressed and have underlying gum pockets.

When the trunk or limb of a tree is girdled

by a canker, the area above the girdle eventually dies. A slight inward curling and drooping

of the leaves is the first indication that the

limb has been girdled. The foliage turns progressively light green to yellow. At this stage,

the leaves hang straight down and are strongly

rolled. If the canker is on the main trunk below

the scafi'old limbs, the entire top of the tree

dies (fig. 42). When the top is killed, several

suckers may initiate near the ground line,

above and below the graft union.

Blossom infection usually is not important

in sweet cherry, but it can be very severe under

climatic conditions favorable to the disease.

Blossom infections may progress into the twigs

and cause shoot wilt; they commonly infect

spurs and progress into the main limbs of the

tree, where they cause characteristic cankers.

Infected blossoms appear water-soaked, turn

brown prematurely, and hang, producing the

symptoms that prompted the common name

"blast."

In some areas, where environment favors

bacterial canker, a great number of dormant

cherry buds are killed. This type of infection

usually is limited to the buds in severely affected orchards in western Oregon; up to 80

percent of the buds may be killed (16).

The first evidence of infection in the buds

shows as a brown necrotic area at the base of

the bud scales in February and early March

(fig. 43). Infection of buds takes place during

fall or early spring; the bacteria enter the bud

between the lower scales (15). Such affected

FIGURE 42.—Three-year-old cherry tree with upper

portion injured by bacterial canker.
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 57

FIGURE 43.—Cross section of a bud damaged by a strain

of Pseudomonas syringae.

buds fail to open, then dry up. When observed

at full bloom the black skeletons of diseased

trees are a striking contrast to healthy trees

(fig. 44). Once an infection is established, the

bacteria may move in the conductive elements

to other parts of the tree (17). Under these

conditions infection may be latent, and the

tree may appear healthy until climatic conditions are favorable; then severe symptoms of

bacterial canker develop rapidly.

Where the leaf-infection phase is severe, application of spring and summer sprays are

effective. Dormant-bud infection can be prevented by applying fall and early spring dormant sprays of bordeaux mixture.

Control measures applied after the canker

phase of the disease is established are seldom

satisfactory. Heavy dormant bordeaux sprays,

such as 16-16-100, have reduced the severity

of symptoms in some cases. Some sweet-cherry

cultivars are most resistant than others, but

none are immune. In some areas relatively

resistant mazzard rootstocks are used for the

trunk and scaffold arms, and the desired commercial cultivars are topworked onto them 12

to 18 inches from the trunk (18). On such

trees, infection stops at the graft union, and

only portions of the tree are lost.

CROWN GALL

This disease occurs widely in cherrygrowing areas, but the amount of damage

attributed to it ranges from severe to slight.

It is characterized by galls, which generally

occur at or near the crown. They are irregular

in shape, varying in size from y^ to 5 inches

on young trees to much larger on mature

trees. The galls are commonly located at the

pruned end of tap roots and along the crown

where injuries have occurred, but may also

occur along the lateral roots. Most nursery

trees with galls are culled out by the nursery;

the grower should not plant trees that are

visibly infected. Growers should always purchase top-quality trees and not buy lower

grades or culls in an attempt to save money.

Some nurseries treat lining out stock by dipping it in a chemical disinfectant before planting. Dipping of all nursery trees before

orchard planting may be advisable in areas

where the disease has given trouble.

Specific control measures have generally not

been listed for fungus and bacterial diseases

because of differences in climate, time of application, and the advisability of coordinating

application with those of recommended insecticides. Many new chemicals are available, and

these should be tested locally before being

applied.

VIRUS AND VIRUSLIKE DISEASES"

Virus diseases present serious production

limitations, but the losses they cause may not

be readily apparent (2, 105). Most do not cause

immediate tree collapse or even eventual tree

" This section was prepared by L. C. Cochran, Oregon

State University, Corvallis, Oreg.

loss. However, affected trees often are debilitated to the extent that yield is reduced by

one-half or more, quality of fruit is lowered,

fruit size is reduced, or the percentage of cull

fruits is increased. Each of these effects reduces

economic returns. Virus diseases are conta-
58 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

V I

Î, f 1»*// »

>,:>»i;>.^'^/

KV,/

PN-3100 PN-SlOl

FIGURE 44.—Sweet-cherry trees in full bloom: A, Buds severely infected by bacterial canker (note lack of blossoms

on lower two-thirds of the tree); B, a healthy tree.

gious, and when affected trees are detected they

have already exposed other trees. In most

cases there is no known method of curing

affected orchard trees. The only control is

avoidance of infection through use of virusfree nursery stock and prompt removal of

affected trees and natural host species. In

older orchards, growers may obtain profitable

crops from trees affected by some of the less

debilitating diseases. However, in young

orchards, it is always wise to replace trees

debilitated by viruses.

Viruses are infectious particles too small to

be seen except with the aid of an electron

microscope. Viruses are transmitted readily by

normal vegetative propagation methods. Graft

transmission of Prunus ringspot and rusty

mottle occurs after 74 hours of contact with a

live inoculum bud, and little cherry virus after

152 hours (50). Aphids, leafhoppers, eriophyid

mites, and nematodes are known to be vectors

of specific viruses. Natural root grafts also

may permit spread of virus from one tree to

another.

Some diseases formerly ascribed to viruses

are now known to be caused by mycoplasma.

Mycoplasma are small organisms, generally

intermediate in size between viruses and bacteria, which are transmitted by insects and

mites and which induce diseases similar to

those caused by viruses.

Nursery trees grown from regularly-indexed

budwood and rootstock seed sources are good

insurance for the grower (76). Several State

nursery improvement programs and an Interregional Repository of indexed material at

Prosser, Wash. (^9), have been of great service

in making better nursery stock available.

X-DISEASE

The designation x, connoting a mathematical unknown, was given to this disease because
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 59

of its unusual symptoms by Stoddard {120),

It occurs in almost all the sweet-cherry growing districts of the United States. It has been

described on cherries under several names including western x-disease, western x-little

cherry, small bitter cherry, western x-wilt and

decline, buckskin, and yellow-red viruses (P^,

96, 104^, 106y 151), In most areas x-disease also

occurs on peach, where it induces more easily

recognized symptoms (59, 151). X-disease has

caused serious losses to sweet cherries in local

areas, particularly in Utah, southern Idaho,

the Dalles area of Oregon, and the Green and

Napa Valleys of California.

In warmer areas, x-disease kills sweet-cherry

trees growing on mahaleb cherry rootstock in

one to two years (95, 96, 101), Trees that

become diseased in midsummer usually wilt

and suddenly collapse, retaining their dried

leaves into the fall. At other seasons, death is

preceded by varying rates of decline, including

cessation of current growth, yellowing and loss

of leaves, and failure of fruit to mature (129),

Roots on affected trees are discolored and die

progressively from the feeder roots to the

larger ones. When symptoms appear in the

tops, necrosis can usually be found in the

cortical tissues of the mahaleb rootstock immediately below the graft union. In cooler

areas, symptoms on affected trees on mahaleb

rootstocks consist of resetting, dwarfing, and

failure of fruit to mature.

In trees on mazzard rootstock, the disease is

less spectacular. The most striking feature is

failure of the fruits to size and mature at the

normal season. Affected and normal spurs are

commonly interspersed, and sometimes normal

and diseased fruits occur on the same spur.

In advanced cases, whole leaders are affected,

bat involvement of whole trees occurs rarely

and only in the last stages.

In California, affected fruits of light-colored

cultivars, particularly 'Napoleon', remain dull

white resembling kid leather, hence the name

''buckskin" (95), On normally dark-colored

fruit cultivars, affected fruits remain dull light

red and fail to size. Affected fruits fail to

develop their normal sweetness and flavor.

Leaf symptoms include various abnormal color

changes ranging from dull green to yellows

and bronze. In Utah, leaves on affected trees

are smaller than normal and commonly develop

enlarged, proliferated stipules (129),

The causal agent is transmitted by a number

of leafhoppers (62, 63, 81), These leafhoppers

feed on diseased plants and then carry the

virus to normal trees in the course of their

normal feeding habits.

Control of x-disease is difficult in some areas,

especially where orchards are near stands of

infected native chokecherries. New orchards

should not be planted adjacent to old infected

plantings, especially those on mazzard rootstocks or near stands of native chokecherries.

Removal of virus host reservoirs near new

orchard sites with herbicides before planting

will materially reduce the incidence of x-disease.

Experimental injection of trees with antibiotics has shown some promise for reduction of

x-disease symptoms.

In areas like Utah, which are favorable to

vectors that breed on cherries, spread has been

particularly rapid. In these areas, infection

may become extensive in orchards on mazzard

rootstocks, which in turn serve as reservoirs

for further spread. In such areas, the use of

mahaleb rootstock with 9 to 12 scaffold leaders

separately topworked has shown promise. The

infectious agent does not move from one sweetcherry leader to the other through the mahaleb

portion of the tree. Diseased leaders can be

pruned back to the mahaleb portion and topworked with a healthy scion, or the other

scions can be allowed to fill in. Use of resistant

cultivars such as 'Long Stem Bing', 'Dicke

Braun', and seedlings of these has also been

effective.

In eastern United States, removal of diseased

chokecherries from the vicinity of the orchard

provides good control. The natural vectors apparently do not breed on cherries, hence do

not spread the disease within the orchard.

LITTLE CHERRY

The little-cherry disease, as the name

implies, is characterized by failure of the fruit

to size and mature normally (U6), On most

cultivars, symptoms are confined to fruits.

Some cultivars, such as 'Van' and 'Sam', when
60 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

infected, produce reduced growth, and some

leaves develop a yellow-bronze color (101).

Many cultivars show no foliage symptoms.

Most of the oriental flowering cherries in the

United States are infected symptomless carriers of the virus. It seems likely that the

little-cherry virus was introduced into the

United States in infected symptomless oriental

cherry trees (100, 102, 10A).

Little cherry was first observed in North

America on commercial sweet cherries near

Nelson, British Columbia, in 1933 (Jf6). It

spread rapidly in orchards along Kootenay

Lake in the 1940's and is now generally present

in most trees in that area (Si). Although the

virus is generally present in flowering cherries,

often growing in yards near commercial

orchards, very little spread has been observed

in most commercial sweet-cherry areas of the

United States. Little-cherry disease, however,

is a serious threat to the cherry industry, and

its spread in isolated local areas indicates its

potential, should conditions become favorable

to the leafhopper vectors. The disease was recognized in commercial sweet cherries in

England in 1955 (89). Subsequently it was

found widespread in commercial orchards in

England and in various other parts of Europe

(88).

Symptoms of little cherry vary with cultivars

and climate areas. 'Lambert' (fig. 45), 'Republican', and 'Hedelfingen' are severely affected. 'Bing', 'Napoleon', 'Black Tartarian',

and 'Deacon' are moderately affected. Some

cultivars are severely affected during the first

year of infection, but fruit size improves in

later years. In areas like the Kootenays, where

climate is conducive to large fruit size, fruit

production has proceeded, with most of the

crop going to the brining industry.

The little-cherry virus appears to be restricted to cherry species. All attempts to infect peaches and plums experimentally have

been unsuccessful (lU). Wilde (138) was able

to transmit the little-cherry virus in British

Columbia with two species of leafhoppers.

Neither of these species are present in England, yet natural spread occurs there. Natural

spread from oriental cherries to sweet cherries

FIGURE 45.—'Lambert' cherry fruits affected with little

cherry, showing a gradient in size as contrasted with

normal fruits at right; A, Side view; B, stylar-end

view.

does not appear to occur in the United States,

but spread from sweet cherry to sweet cherry

does occur.

There are a number of viruses that cause

reduced fruit size and abnormal maturity.

Albino cherry, described from southern

Oregon, induces fruit symptoms with some

similarities to those of little cherry, but this

disease usually kills most cultivars, particularly 'Bing' growing on either mazzard or

mahaleb rootstocks. Small fruits that fail to

mature are characteristic of x-disease, especially on trees growing on mazzard rootstock.

This disease, however, kills trees growing on

mahaleb rootstock, and the virus will infect

peach and other Prunus hosts. Diagnosis in

the field may be difficult and may require

tissue transmission to indicator plants, such as

'Van' (139).

No satisfactory control is known for the

little-cherry disease. Growers generally agree

that oriental flowering cherries near commercial orchards are a hazard and should be removed. Wild mazzards and other cherry species

should be removed from orchard perimeters.

Growers should observe their trees carefully

at harvesttime, and any suspicious trees

should be removed promptly.
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 61

ALBINO

The name albino was given to this disease because fruits on affected trees of most

cultivars remain small, immature, and white

at normal maturity time (152). Unlike some

of the other diseases characterized by small

fruit, albino is a tree killer. Trees often die

during the first year of infection and usually

in the second and third year. Fortunately, this

disease has not been found outside of the Rogue

River Valley of southwestern Oregon.

The symptom of albino have characters in

common with those of some strains of x-disease.

In early spring, branches on affected trees

start to die back, and by summer the leaves

become uniformly golden bronze to olive

brown, and the margins roll upward. New

growth induced from terminal buds late in

the summer is small and rosetted. Fruits remain small and immature, even those on darkred-fruited varieties turn white (fig. 46). Most

of the fruits on affected trees drop before

harvesttime, but some of the small white ones

remain. As in x-disease, trees on mahaleb rootstock die more rapidly than those on mazzard.

Spread may be very rapid; all trees in some

orchards become diseased in 2 or 3 years {125).

Albino is distinguished from x-disease by

the more drastic symptoms produced on sweet

cherries and by the failure of the causal virus

to infect peaches.

PN-310

FIGURE 46.—^, Dying albino-affected sweet-cherry tree (left) and nearby healthy tree ; B, branch of albinO-affected

tree showing late-season symptoms; C, terminal from a similar tree, showing small green and older greenishbronze leaves; and D, 'Lambert' fruits affected by albino (left) and normal fruits.
62 AGRICULTURE HANDBOOK NO. 442, U.S. DEFT. OF AGRICULTURE

Albino still poses a threat to sweet cherries

in other areas. Care should be taken to prevent movement of the causal agent out of the

area. A number of partially tolerant cultivars

have been developed in the area and are available for local planting.

PRUNUS RINGSPOT

Many trees in sweet-cherry orchards of the

United States are infected with one or more

strains of the ringspot virus (7^, 77). Symptoms range from obscure chlorotic rings and

Unes to brilliant chlorotic and necrotic patterns, often with concentric rings (fig. 47).

PN-3104

FIGURE il—A, Twig of 'Yellow Spanish' cherry affected with tatter leaf; B, affected leaves of the

same cultivar.

Where necrosis is involved, leaves may become

shot-holed, shredded, and tattered. Symptoms

are most striking in new growth and tend to

fade later in the season. They are also more

pronounced the first year of infection and, in

some trees, the disease becomes entirely latent

after the initial stages. Growth of affected trees

is reduced, but this is not evident unless

healthy trees are available for comparison.

Ringspot is seed-transmitted (23, 28, 39)

and is spread in the orchard by infected pollen

{51). When nursery stock is propagated from

infected materials, a poor set of buds and poor

growth usually results {77).

The control of ringspot in commercial

orchards is very difficult. The first essential

is to start with virus-free nursery stock. To

produce this, the nurserymen must have both

virus-free seeds for rootstock and virus-free

budwood. Because the ringspot virus is pollenborne, new orchards will need to be sufficiently

isolated from old orchards to prevent infections through pollen carried in by bees. The

increased vigor and survival of trees during

the early years of new orchards will pay for

the extra expense of virus-free nursery stock.

MOTTLE LEAF

Cherry mottle leaf occurs in localized areas

of the cherry-growing regions of western

United States and Canada {98, 103). Leaves

on affected trees develop characteristic mosaic

and mottled patterns and show variable

amounts of distortion and dwarfing {98) (fig.

48). Fruit on trees with pronounced leaf

symptoms is small, late to ripen, insipid in

flavor, but usually not misshapen. Growth is

stunted, giving affected trees a rosetted appearance.

All cherry cultivars, both sweet and sour,

are susceptible, but 'Bing' and 'Napoleon' are

the most severely affected cultivars. Variability in symptom expression is due not only to

varietal tolerance but also to the fact that different strains of the virus induce mild or

severe symptoms. Symptom expression is most

pronounced in the spring and tends to become

less so in summer and fall. Mild cases may

become entirely masked late in the season, but
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 63

PN-3106

FIGURE iS.—A, 'Napoleon'; and B, 'Bing', cherry leaves

affected by mottle leaf. C, Branch of 'Bing' cherry

affected by severe mottle leaf, showing symptoms in

the new tip growth.

they will develop characteristic symptoms in

new growth the following year.

The prevalence of cherry mottle leaf is greatest in the interior valleys, near foothills, especially near native stands of wild bitter cherry,

Prunus emarginata (Dougl.) Walp. The bitter

cherry is a natural host of both the virus

and the eriophyid mite, the vector that carries

the causal virus to cultivated cherries (L. S.

Jones, unpublished).

Mottle leaf can be efficiently controlled

through avoidance of sites near native stands

of bitter cherry or through removal of the

bitter cherry before the new orchard is planted.

Several of the newer herbicides have made

removal of wild-cherry stands feasible. Care

should also be taken to insure that propagating wood is taken from trees free of mottle

leaf.

RUSTY MOTTLES

Several types of rusty mottles affect sweetcherries (69, 97, 103, 107). These are distinguished on the basis of their effect on different cultivars or on their total effect on trees.

All induced mottled patterns are composed of

rings, spots, and irregular lines, which are bordered by yellowish to rust-colored areas. Affected trees appear nearly normal in the

spring but may show some delay in foliation

and flowering. Rusty brown spots of varying

size and shape develop on the older leaves 3

to 5 weeks after petal fall. Symptoms may develop rapidly in warm weather. The affected

leaves become senescent and drop. Severity of

leaf fall varies in different areas, in different

cultivars, and with the different strains of the

virus. The effect on fruit is generally proportional to the amount of defoliation. On moderately to severaly affected trees, the crop is reduced. Fruit is retarded in maturity and fails

to develop normal size and flavor, but it is not

misshapen.

The rusty mottle originally described {97)

from Washington and Oregon affects the major cultivars of sweet cherries, 'Bing,' 'Napoleon', and 'Lambert', about equally and generally does not kill the trees.

The necrotic type of rusty mottle (also referred to as Lambert mottle) (69) generally

produces more severe effects, causing dieback

and often death of trees. The 'Lambert' cultivar and certain mazzard seedlings are more

severely affected than 'Bing' and 'Napoleon'.

'Black Tartarian' can be infected but does not

show symptoms. The leaf spots usually begin

as necrotic areas, with the surrounding tissue

subsequently becoming chlorotic and colored.

Necrosis also occurs in buds, leaf spurs, and

bark. This damage ' results in bare, rangy

branches with corresponding amounts of dieback, and sometimes with gum-filled blisters

and cankers in the bark.

Selection of propagation materials from nonaffected trees is the first essential for control.
64 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

There is little evidence indicating natural

spread in orchards, but good evidence links

outbreaks to propagation from diseased sources.

Diseased trees produce light crops of inferiorquality fruit and, therefore, should be removed

and replaced with good trees.

RASP LEAF

Cherry rasp leaf occurs in all the sweetcherry growing areas of the United States.

It has caused severe losses in local areas in

Washington, Colorado, and Oregon. The disease

is characterized by enations that grow from

interveinal tissue on the lower sides of the

leaves. The enations consist of enlarged glands

and various types of excresences, from small

tumors to outgrowths resembling serrated leaf

edges (7, 9, 99). In severe cases, leaves may

be drastically distorted. Where a number of serrated excresences are parallel, they resemble

somewhat the teeth on a coarse rasp, hence,

the name rasp leaf (fig. 49). Trees may be

partly or completely affected. Usually when

the disease appears on one branch, it continPN-3106

FIGURE 49.—'Napoleon' cherry leaves affected by rasp

leaf, showing enations and distortions.

ues to spread in succeeding years until the

whole tree is involved. Damage to diseased

trees consists of retardation in growth and reduction in size and quality of the crop. Occasional enations are common on sweet-cherry

leaves (7). Usually these occur on only a few

leaves and are easily distinguished from rasp

leaf.

Since rasp leaf essentially destroys the productiveness of sweet-cherry trees, diseased

trees should be removed promptly. Spread does

occur in orchards but is usually slow. Care

should be taken to obtain propagation wood

from trees known to be free of the disease.

TWISTED LEAF

Twisted leaf has caused serious losses in a

few orchards in Washington State and the adjoining areas of the Okanagan Valley of British Columbia (24, 68). It damages the 'Bing'

cultivar, but the causal virus can also infect

other sweet and sour cultivars. Affected 'Bing'

trees are severely stunted and appear rosetted.

Necrosis of tissues in the midrib and lateral

veins causes leaves to be small and distorted,

with irregular upward rolling. Mottling may

occur either as small yellow spots or more profusely with irregular lines and blotches (fig.

50). Severe defoliation may occur in midsummer (99). Fruit on severely affected trees usually is small and misshapen, and ripens unevenly. Necrosis occurs both in the stem and

in the misshapen fruit. Symptoms usually are

mild on cultivars except 'Bing', and some infected hosts may be symptomless.

Control of cherry twisted leaf consists principally in the use of disease-free propagating

materials. Spread in some orchards has been

traced directly to grafts of infected pollinizer

cultivars in which the disease was latent. Some

slow natural spread has occurred. Severely affected 'Bing' trees are worthless and should

be removed.

BLACK CANKER

The symptoms of black canker are spectacular on sweet cherry, but this virus disease is

relatively unimportant because of its limited occurrence and the fact that it does not spread
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 65

naturally in the orchard. Affected trees bear

reasonable crops but suffer some from dieback,

which reduces the fruiting wood. The disease

affects most sweet-cherry cultivars but has

been seen principally on 'Napoleon' in orchards

propagated from diseased wood.

Cankers start on one-year-old twigs as swollen blisterlike areas, which eventually split

lengthwise. These areas grow into rough, black

cankers of variable size determined by the size

of the affected branch (fig. 51). Some infected

trees are severely cankered, whereas others may

have relatively few lesions. No abnormal leaf

or fruit symptoms have been observed (153).

Black canker should be avoided in nursery

propagation. Diseased trees need not be removed until they become unprofitable.

SPUR-INDUCING VIROSIS

Interest in semidwarf, precocious, genetic,

spur-type apples has focused attention on a

search for this character in other fruits. In

1963, a 'Bing' tree with a spur-type habit was

found in the Yakima Valley of Washington.

Considerable local interest developed in making

use of this apparent mutation. In 1965 Blodgett

and others (8) and later Guengerich and Millikan (57) showed that the growth habit was

virus-induced and was not genetic in nature.

Although the virus appeared to have no appreciable effect on fruit size, quality, or productiveness of the 'Bing' cultivar, subsequent

work has shown that it causes severe dwarfing

on other sweet cherries, particularly 'Van',

'Windsor', 'Gil Peck', and 'Badacsoner'.

SHORT-STEM VIROSIS

The stems of fruits on trees affected by

short stem are approximately one-third to onehalf the length of normal ones. They are usually distorted and twisted because of necrotic

tissue in the vascular area. Fruits are also distorted and may have corky tissue in the stem

end. Affected 'Bing' trees show reduced vigor.

In the second and succeeding years of infection,

they may develop dieback and bark blistering.

'Napoleon' is less affected than 'Bing' but also

shows reduced vigor and dieback. Other cultiFIGURE 50.—'Bing' cherry leaves and fruits afifected by

twisted leaf disease.

vars have shown the short stem and leaf distortion, but there was less reduction in vigor.

The disease was originally described (1) in

Montana, where it appears to spread slowly

in orchards. It was found also in Oregon, and

its host range was reported (22). Short stem

is regarded as potentially serious; therefore,

any diseased trees should be removed promptly.

VIRUS DISEASES OF LESSER

IMPORTANCE

Sweet cherries are susceptible to a large

number of viruses that cause minor or no

damage. Some of the recently recognized virus

diseases are potentially serious but are of very

limited distribution. Others, of wider distribution, either cause little damage or may exist

without symptoms. Some may reduce vigor but

induce no characteristic symptoms. Viruses

that induce symptoms but cause minor dam-
66 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

PN-3108

FIGURE 51.—Two- to 4-year-old twigs of 'Napoleon' cherry affected by black canker disease.

age are: Mora (73), rugose mosaic (83), freckle

fruit Í1-Í2), a blossom anomaly (21), line pattern, rose mosaic, peach mottle, and cherry

bark blister (122). Tobacco mosaic and cucumber mosaic viruses have been found naturally occurring in some orchard trees. Viruses

that occur commonly but that may not cause

symptoms in cherry species are sour-cherry

yellows (84), green-ring mottle (48, 108), and

prune dwarf. Undoubtedly sweet cherry is susceptible to some of the viruses described on

other roseaceous hosts.

CHERRY BORON ROSETTE

Cherry boron rosette is characterized by

sjrmptoms typical of boron deficiency. Symptoms include narrow leaves rolled upward toward the midrib and shortened rosetted growth

(fig. 52). Affected branches bear no fruit. The

disease was discovered in Oregon in 1966 (75)

and has subsequently been found in several localities in the Northwestern States. The disease

has spread rapidly and has been transmitted

with the black cherry and green peach aphids.

A strain of cucumber mosaic virus has been

isolated from several affected trees. Both foliage symptons and lack of crop have been corrected with boron applied in the normal spray

schedule.

OTHER DISEASE PROBLEMS

New or different disease problems may occasionally occur on sweet cherries. They should

be called to the attention of your local Extension Agent if they seem potentially dangerous

to production in your area. The importance of

preventing propagation of virus-infected trees,

by planting only trees that have been grown

under a supervised program, cannot be stressed

too strongly.
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 67

HARVESTING AND MARKETING"

Sweet cherries are among the most delectable

of fruits, and their successful marketing depends on the fruit's having good quality when

it reaches the consumer. Fruit with good quality has an attractive appearance and desirable

texture and flavor.

To insure top quality for the consumer,

cherries must be harvested at the right time

and handled correctly from the orchard to the

market.

For the fresh market, cherries are picked

with stems attached. In picking, the stems are

grasped near the bases with thumb and forefinger and turned back against the spur. Care

should be exercised not to cause undue injury

to the stems or break the fruit spurs.

If the stems are not injured in picking, they

shrivel at a rate that depends on temperature

and humidity, but they do not necessarily turn

brown. If the stems are injured, rapid browning occurs as a result of enzymatic action {113).

Mechanical harvesting of sweet cherries for

long-distance shipment has not appeared feasible with present machines and tree-training

systems. The cherries tend to detach from the

stems when shaken {121), and they are usually bruised too severely to withstand breakdown during the long transit and holding period {12Jf). Both of these factors increase

weight loss and shrinkage. Handlers usually

require fruit with attached stems and use the

stems as an index of condition of the fruit.

However, sweet cherries that are to be brined

immediately have been harvested successfully

by machine {82, 118, 12i). The chemical SADH

(succinic acid 2,2-dimethyl hydrazide) hastens

color development without loss of firmness {A,

111), and enhances uniformity of ripening.

Ethephon (2, chlorethylphosphonic acid) enhances abscission of sweet-cherry fruit {líJí)

and, consequently, may reduce bruising from

reduced shaking force necessary. Either chemical should be applied on an experimental basis

" This section, except the parts on mechanical harvesting and chemical treatment, was prepared by H. A.

Schomer, formerly plant physiologist, Market Quality Research Division, Agricultural Research Service,

Wenatchee, Wash. Retired.

PN-3109 PN-3110

FIGURE 52.—Symptoms of cherry boron rosette: A,

Sparse growth and dieback; B, long cup-shaped leaves.
68 AGRICULTURE HANDBOOK NO. 442, U.S. DEFT. OF AGRICULTURE

only. Clearance of these chemicals for these

uses on sweet cherries should be ascertained

before either is applied to fruits to be marketed.

PICKING MATURITY

The tonnage per acre and the dessert quality

are influenced appreciably by the maturity of

the fruit when harvested. Harvesting too early

results in poor quality and loss of tonnage. Immature fruits are astringent and sour, and

they shrivel severely after harvest. Sweet cherries are often picked too soon because of fear

that rains during the harvest period will cause

serious cracking of mature fruit.

Cherries picked when fully ripe or overmature have a short shelf life. The stems

darken severely and dry up, and the fruit

soon becomes dull and aged in appearance (fig.

53). It loses flavor rapidly and is increasingly

susceptible to decay.

INDICES OF MATURITY

The guide most commonly used for judging

harvest maturity is color. Soluble solids, an additional guide, indicate the sugar content,

which is correlated with dessert quality. Both

color and soluble solids should be used in judging when to harvest cherries. The California

State Department of Agriculture uses a color

chart to show a minimum acceptable maturity

for dark sweet cherries.

Color

Color changes are definitely associated with

maturity. The dark-colored cultivars of sweet

cherries, such as 'Bing' and 'Lambert', change

from light red through shades of dark red,

mahogany, and even black during maturation.

Color develops independently of sunlight; the

inside, shaded cherries attain the same color

as those exposed. A light mahogany to mahogany color at harvesttime is recommended for

handling and shipping.

In the light-colored varieties, such as 'Napoleon', 'Corum', and 'Rainier', only part of the

surface is colored by red blush, and the ground

color is visible on the remainder of the fruit.

PN-3111

FIGURE 53.—Cherries with steins that have been allowed to shrivel (above), and with stems still green

and turgid (below). Much of the moisture in a picked

fruit is lost through the stem.

During maturation, the ground color changes

gradually from green, through pale yellow, to

light gold at full ripeness.

Soluble Solids

Although the soluble-solids content of expressed juice is a fair index of maturity, in

California, color is considered the more reliable

index. In more than 800 samples from commercial orchards, soluble solids varied with the

year of production, with the district in which

the cherries were produced, and with the size

of the crop on the trees.

Soluble solids are readily determined with a

hand refractometer. Taste or flavor is a substitute for the actual measurement of solids

because of the close association of flavor and

sugar content. Quality in cherries does not improve after harvest, nor does the sugar content

rise. For good quality in 'Bing' cherries, soluble
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 69

solids of about 19 percent are generally considered minimum, while 17 percent is satisfactory for 'Lambert'.

Other Maturity Factors

Flesh firmness and elapsed time from full

bloom both have been tested as methods of

diitermining harvest maturity. Special pressure

te sters have been devised to determine the rate

o1 softening of cherries as they approach maturity, but the rate of softening is so slow

tliat the pressure test is not practical as a means

of measuring maturity. Elapsed time from full

bloom to optimum maturity is too variable

f]'om season to season to permit the employment of this factor, except to indicate approximately when harvesting operations should

start.

Certain chemical treatments, in conjunction

with nitrogen management, have potential for

the control of harvest maturity and consequently more efficient use of available labor.

SADH (succinic acid—2,2-dimethylhydrazide)

at 500 to 2,000 p.p.m. advanced maturity of

'Lambert' cherries 4 or 5 days (4, 111). SimihiT advanced maturity was obtained from the

Siime material at 1 or 2 lb. per 100 gal. water

applied 2 weeks after bloom, but soluble solids

were not increased correspondingly in unpublished Washington State experiments by Proebsting. Some deleterious side effects noted were

slight advancement of blossoming, reduced

fruit-bud hardiness, and increased fruit drop.

In the same tests, gibberellic acid at 10 p.p.m.

applied 3 weeks before harvest delayed maturity several days. These materials are not

cleared for use at these timings, and any use

should be experimental only. The apparent reduction in quality suggests caution until more

suitable chemicals, concentrations, and timings

are found for these potentially useful chemicals.

FRUIT HANDLING

Cherries should be picked during the cool

part of the day, if possible. In hot weather,

transpiration from the trees is excessive. A

v/ater deficit may exist in the fruit late in the

day, which will be expressed as severe pitting

after a few days in storage or during marketing. To maintain fruit turgidity and minimize

pitting, the orchard soil should be kept moist

up to harvesttime.

After harvest, the cherries should be protected against moisture loss by keeping them in

the shade while they are in the orchard. Covering them with moist canvas or other protective

material is also advisable. If polyethylene is

used to reduce moisture loss, an additional

opaque cover should be used for shading the

fruit (fig. 54). Exposure to sun or wind causes

unnecessary transpiration and reduces the shelf

life of the fruit. It is advisable not to leave

the fruit in the orchard longer than necessary,

but to haul it to the packing house or cold storage as promptly as is practical. The fruit

should be covered during hauling, especially

for long distances. Cherries hauled in open

trucks may be covered with moistened canvas

or similar materials (fig. 55). Sheets of plywood are effective protection against moisture

loss when used as covers for pallet loads of

cherries hauled in straddle carriers. Excellent

results have been obtained by using closed

trucks with blocks of ice for refrigeration and

humidity. Upon delivery to the warehouse, the

cherries should be placed immediately in cold

storage and held there until they are packed.

They should be covered in storage to reduce

moisture loss.

Lugs of cherries that were covered with canvas and similar materials during the interval

from harvest to packing lost from 0.4 to 1.0

percent of their weight through transpiration,

while unprotected lugs of fruit lost from 1.8

to 2.1 percent of their weight during the same

period (unpublished data). These figures vary

with the climatic condition, the length of time

the fruit remains in the orchard, the time during hauling, and the storage period before

packing.

PACKAGING

Cherries that are to be shipped to freshfruit markets are belt-sorted to remove rejects

and are sized mechanically. The recent invention of cluster cutters has greatly advanced

packing methods (fig. 56). As the fruit is carried along on moving belts, the clusters are cut

apart by rotating saws or blades, and with
70 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

stems still attached, the individual cherries are

then free to be mechanically sized by the use

of diverging rollers (fig. 57).

Water is sprayed over the fruit for a lubricant during cutting and sizing, and it also

functions as a wash. A fungicide is often incorporated into the final spray. Subsequent decay may be reduced 30 to 50 percent (87).

Containers

Most sweet cherries that are shipped for the

fresh-fruit marlcet from the western States are

PN-3112

FIGURE 54.—Harvesting cherries into a pallet bin. When bin is filled, the polyethylene film will be placed over

fruit to reduce moisture loss, and the corrugated paper cover will be added to shade the fruit.
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 71

packed in boxes or lugs that hold 10 to 20

pounds of fruit. The double row-faced pack,

which has been the standard pack in the west-

^

FIGURE 55.—Truckload of cherries covered with moistened canvas for protection during hauling to warehouse.

ern States for many years, holds 15 pounds

of fruit and has inside dimensions of

3 X 11 X 18 inches. However, the automatic

sizer lends itself to the easy and less expensive

method of jumble packing from the belts that

carry the sized cherries. Consequently, most

cherries are now jumble packed into wooden

boxes or divided fiberboard boxes that hold

20 pounds of fruit.

In the Pacific Northwest, sealed polyethylene liners are nearly always used with all

types of boxes (fig. 58). Within the sealed

"poly" liner, which is usually 1.25 or 1.5 mils

thick, the atmosphere becomes modified as

oxygen is consumed and carbon dioxide is liberated by the respiring fruit. Levels of carbon

dioxide and oxygen within the sealed liners

at 31° F. become stabilized at about 6.5 and

9.0 percent, respectively. Decay is retarded by

the carbon dioxide, which, together with the

high moisture within the liner, preserves fruit

brightness and stem freshness. The cherries

may be held in sealed polyethylene liners in

PN-3114

FIGURE 56.—Cherry-cluster cutter. The stems of the clusters ride up on the steel fingers and are cut apart by

the rotating saws.
72 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

if^) #W

7isns

PN-311B

FIGURE 57.—Cherry sizer. The sized cherries drop through diverging rollers onto moving belts that carry fruit to

the packing stations.

cold storage at 30° to 31° F. for 2 weeks after

harvest and still be shipped by freight to eastern markets and arrive in acceptable condition.

The poly liners must be ripped or torn open

when the packs are removed from refrigeration to higher temperatures. This prevents the

accumulation of excessively high levels of carbon dioxide and the reduction of oxygen to

very low levels, both of which are deleterious

to the fruit (5^, 55).

PRETRANSIT HOLDING AND

SHIPPING

Cherries should be cooled as soon as possible

after harvest to provide the maximum length

of storage life. Because cherries are very perishable, prompt shipment after harvest is the

best insurance of good quality to the consumer.

However, the harvest season is short, and a

large volume of fruit must be picked during a

short time. To prevent market gluts, it is sometimes desirable to store some of the fruit until

the marketing situation improves. In general,

a storage period of about 14 days at 32° is

permissible; this still allows enough time for

shipping and marketing.

Precooling

The rapid removal of field heat by refrigeration from produce before it is shipped is

called precooling. It was advocated for westerngrown sweet cherries in 1916 when it was observed that a substantial reduction in decay
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 73

PN-3U6

FIGURE 58.—Lugs of cherries packed in polyethylene

liners, before and after sealing.

occurred when cherries were precooled to 40° F.

before a 10-day transit period (93).

The customary precooling procedure in the

Pacific Northwest is to cool the lug boxes or

bins of cherries overnight in cold-storage

rooms to temperatures between 36° and 40° F.

After they are packed the next day, the cherries

are returned to cold storage, where they are

cooled to approximately 32° before shipment.

The rate of cooling is proportional to the air

velocity. It is about 1.9 times faster in an air

blast of 375 ft. per min. than in still air at

31°F. (53).

Pallet loads of cherries were cooled 1.9 to 6

times faster in a cooling tunnel where the

air was passed over the fruit at a velocity of

from 300 to 800 f.p.m. than in a room with

auxiliary fans and an air velocity of 50 to 120

f.p.m. (112). When high-velocity air (1,790

to 2,685 f.p.m.) was directed into open, unlidded individual lugs of cherries, the cooling

rate was 9 to 40 times faster than room cooling.

Hydrocooling uses refrigerated water rather

than air as the cooling medium. The fruit may

be immersed into a tank of water, or water may

be flooded over and through the fruit. The water

may be cooled with crushed ice or with a mechanical refrigeration system. In either case,

the water temperature should be maintained as

near 32° F. as possible. Loose cherries cool 145

times faster in ice water at 32° than packaged

cherries in still air at 31° F. (53). Only seven

minutes were required to cool cherries from

65° to 33.7° when they were immersed in an

ice-water bath maintained at about 32°. There

is some hesitancy by shippers to use hydrocooling for sweet cherries because of fear that

the process may cause cracking and increase

decay. However, cherries may be hydrocooled

for at least 20 minutes without cracking or

without appreciable increase in the amount

of decay during subsequent transit at 40°. The

appearance of the hydrocooled fruit is comparable to that of fruit cooled in air at 32°

with a relative humidity of 85 percent (52).

Mechanically refrigerated cars are now

available for much of the sweet-cherry crop of

the western States. Although the cherries are

usually at least partly precooled before they

are loaded into cars, the mechanically cooled

cars have sufficient refrigeration capacity to

accomplish some additional cooling in transit.

Shipping

About 28,000 tons of fresh sweet cherries

are shipped from production areas in the Pacific Coast States in refrigerator cars during

seasons of good crops. With the rapid increase

in number of mechanical refrigeration cars in

recent years, many are now available during

the cherry-shipping season. By 1964, practically all the western-grown cherries were shipped in mechanical cars. Their use greatly

simplifies shipping procedures, and their performance has been very satisfactory.

Before mechanical cars were available,

standard and fan-equipped refrigerator cars

were pre-iced to full bunker capacity before

loading of the fruit was started. This was done

to remove much of the heat from the car

structure before the fruit was loaded into the

car. The cherries were usually shipped under

standard refrigeration, which means replenishing the ice at all regular icing stations enroute. Enough salt to equal 2 or 3 percent of

the weight of ice placed in the bunkers was

usually added at the initial icing and at each

re-icing.
74 AGRICULTURE HANDBOOK ND. 442, U.S. DEPT. OF AGRICULTURE

Formerly about 1,000 pounds of dry ice was

placed in the doorway bracing after loading

was completed, and additional dry ice was

added to the bunkers at intervals in transit.

The practice was primarily for the beneficial

effects of the carbon dioxide gas, which

evolved from the dry ice and which, if present

in s'ufRcient concentration, retarded decay

development and preserved the bright color of

the fruit. The effectiveness of the practice depended on the gas-tightness of the cars, little

or no benefit being obtained in leaky cars.

The use of polyethylene liners in cherry

packages, in which an effective level of carbon

dioxide is maintained, makes use of dry ice

unnecessary.

A substantial percentage of the sweet-cherry

crop for fresh market is transported by truck

and trailer. Those vehicles that are used for

hauling cherries long distances are insulated,

and most of them are equipped with mechanical refrigeration. The refrigeration practices

recommended for rail transportation apply

equally to shipment by trucks.

Limited shipments of cherries from the

Pacific Northwest to large terminal markets

by air have been made. Such shipments are

feasible only for large, premium-quality fruit.

PROCESSING

Sweet cherries are well adapted to a number

of processing uses. About two-thirds of the

total production in the United States is channeled into processing outlets. As high as 50

percent of the total production is brined. Therefore processing is an indispensable outlet to

the industry. Particularly in areas where

large fruit size is difficult to obtain for fresh

markets, processing is the major, if not the

only, outlet available. Even in the more favored

producing areas, processing provides the necessary market for smaller sized fruit, which cannot be shipped profitably to distant fresh markets.

BRINING

Brined cherries are properly matured, whole

cherries of similar varietal characteristics

packed in a solution of sulfur dioxide of sufficient strength to preserve the cherries, usually with the addition of hardening agents

(136). The cultivars commonly used for brining are 'Bing', 'Lambert', 'Napoleon' (Royal

Ann), and 'Republican'.

While it is possible to brine cherries at almost any stage of ripeness, best quality is

obtained only at certain stages of maturity.

Cherries for brining should not be overripe,

since soft cherries may result, and blemishes

may reduce the amount of fruit suitable for

U.S. No. 1 grade. If the cherries are picked

too early, they will tend to have more seed in

proportion to the amount of flesh and will be

more difficult to pit cleanly.

Only cherries of good quality should be

brined. Spoiled, damaged, belt-rejects, and

other substandard fruit should not be used.

Mildewed and overripe fruit will show

blemished skin after brining and be difficult

to bleach. Secondary bleaching permits salvage

of blemished fruits, however. Fruits harvested

mechanically should be brined immediately,

in the orchard if possible (135).

The Brine

Three brine formulations are in general use.

Each is described in detail in ARS publication

74-123 (132). One method of formulating a

suitable brine is described hereafter.

The following strengths of solutions have

been found suitable for brining cherries:

Strength

(percent)

1

iy2

so, Ca{OH)s

pounds per 100 gallons

8.4 5

10.5 61^

12.6 71/2

*^ This section was prepared by H. Y. Yang, food

technologist, Oregon Agricultural Experiment Station,

Corvallis, Ore.

Hydrated lime should be fresh and unslaked. A

lime with about 70 percent of available calcium

oxide is suitable for this purpose. If SO2

strength is lower than that desired, it will be

necessary to add more SO2. The amount to add
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 75

can be roughly calculated from the following

formula :

Percent difference x gallons x 8.4

100 = lb.

SO2 to add, where percent difference is the

percent SO2 desired minus percent SO2 found.

Some briners modify this brine in anticipation

of latent softening tendencies of the fruit, or

simply as a safety factor against softening.

This is usually done by use of additional calcium in the form of calcium hydroxide or calcium chloride. Great care must be exercised in

altering the brine drastically. If too much calcium is used with firm brining fruit, the pits

may cling so tightly that difficulty is encountered in the mechanical pitting operation. Drastic changes in pH of brine will be caused by

excess lime, resulting in softening or cracking

of fruit (147).

Where calcium chloride is used to provide

extra calcium, in addition to that supplied by

lime in the preparation of regular brine, the

approximate amount to use will vary between

0.5 and 1.0 percent, that is, between 4 and 8

pounds of calcium chloride per 100 gallons. This

is in addition to the lime used. The actual

amount must depend on judgment concerning

condition of the fruit.

Care should be taken to see that no iron

comes in contact with the brine, since it will

cause discoloration of the cherries during processing. Use stainless steel, wood, or concrete

(fig. 59) for construction of tanks, vats, and

equipment.

When the sulfur dioxide solution is made by

bubbling, a perforated tubing is inserted to

the bottom of the tank. Floating wooden lids

may be used to keep the bubbles from breaking

on the surface.

Brining Process

Cherries are washed with (fig. 60) or without detergent before they are placed into the

brining solution.

In brining cherries, always partly fill the

tank with brine before adding the fruit in

order to minimize bruising or smashing the

PN-3117

FIGURE 59.—These storage tanks for brined cherries are constructed of redwood with fiberglass covers. The tanks

stand on ground beneath the upper deck shown. They are 10 feet high and 16 feet in diameter. Each tank has a

capacity of 13,000 gallons and holds 27 1/2 tons of cherries.
76 AGRICULTURE HANDBOOK NO. 442, U.S. DEFT. OF AGRICULTURE

PN-3118

FIGURE 60.—In recent years, some cherry briners wash their cherries with dilute detergent solutions before brining

One type of washing equipment is shown here. Cherries are conveyed to the detergent tank shown in the center.

They then go through a series of sprayers to remove the detergent before they are flumed to the brining tanks.

Tank on right is for holding detergent solution.

fruit. Cherries should be covered with brine

at all times. Because of temporary softening

of cherries during the first 20 to 40 hours

in brine, large tanks should only be half-filled

until the fruits become firm. Otherwise cherries on the bottom of full tanks become distorted and damaged.

It is desirable to place a sheet of polyethylene

film on the surface of the brine during the

entire brining process. The film can be used

on storage tanks of brined cherries that do

not have permanent lids or on brine preparation tanks. It will prevent loss of sulfur dioxide

by vaporization or dilution of the solution by

rainwater. Place some SO^ solution or other

suitable material on the polyethylene film to

weight it down in order to maintain a good

contact between the film and the brine surface.

In windy areas, the film may have to be

cinched down by wooden frames or other devices. Use of the film cover depends on the

individual briner's type of operation and

physical setup. It is advisable to try the film

first on one or two tanks to determine whether

it is advantageous. Only high-quality foodgrade polyethylene film should be used.

In recent years, some briners have used

bulk boxes for holding and transporting brined

cherries (fig. 61). These boxes are made of

wooden staves, lined with heavy paper and 6-

mil polyethylene film. A bunghole is provided

through the wooden lid to facilitate withdrawing or replenishing brine. Each box is

about 4' X 4' X 2' high and holds approximately

the equivalent of four barrels of brined cherries. The boxes are constructed for stacking

and palleting. They are particularly useful

when cherries are brined in the field.
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 77

Testing the SO^ Solution

Titration to determine the SO2 content of

brine often is done with 0.1 normal standard

iodine solution, using a fixed amount of brine.

Put 10 ml. of brine in a flask. Add 100 ml. of

distilled water, a few drops of 1:3 sulfuric

acid, and a few drops of starch indicator.

Titrate with the iodine solution until a light

blue color persists for about 30 seconds. One

ml. of 0.1 normal iodine used is equivalent to

0.032 percent of SO2 in the solution. By multiplying 0.032 by the number of ml. of iodine

used, the percent of SO2 in the brine is obtained.

An alternative method of testing the SO2

solution can be used. Introduce 125 ml. of

distilled water into a 500-ml. Erlenmeyer flask.

Pipette 25 ml. of standard iodine solution

(0.2 normal) into the flask. Add a few drops

of starch solution (1 percent soluble starch)

and titrate with the SO2 solution from a burette or a graduated pipette. Shake the flask

constantly. As the reaction nears completion,

the color of the iodine solution becomes purple.

PN-3119

FIGURE 61.—Wooden tote boxes reinforced with corrosion-resistant metal brackets are used to hold and transport

brined cherries. Heavy paper and plastic film are used as liners. Note that the boxes are constructed for stacking and palleting.
78 AGRICULTURE HANDBOOK NO. 442, U.S. DEFT. OF AGRICULTURE

At this point, add the SO2 solution very slowly.

At the point where one drop dispels the color

from the iodine solution, stop the titration

and read the volume used. Always read to

the bottom of the curved surface of the SO2

solution in the burette or pipette.

Now refer to the chart (fig. 62) to obtain

the strength of the SO2 solution. Move a pencil

point to the right from the zero on the bottom

line of the chart until the number of milliliters

(ml.) of the SO2 solution used in the test is

reached. Then move upward from the bottom

of the chart until the curve is intersected.

From this point of intersection, move the

pencil point horizontally to the left edge of the

chart. Then read the strength of the SO2 solution from the vertical reference line at the left

edge of the chart.

Control and Observation

After cherries are brined, they should be

observed daily {132). The SO2 content of the

brine should be checked and the degree of

bleach noted. Always keep in mind that there

must be a quantity of free sulfur dioxide ; otherwise, the product will spoil. Tying up all the

sulfur dioxide with lime should, by all means,

be avoided. The SO2 concentration should be

maintained at about % percent during storage

and shipping.

30

2.5

Q2.0

Z)

-J

O

C/D

CVJ O I s

X

»—

O

2: ÜJ

^ 1.0

C/D

0.5

0.

1

\

\

V

\

\

\

X

^^"

0 10 15 20 25 30 35 40 45 50 55 60

ML. SO2/25 ML IODINE

FIGURE 62.—Titration curve for SO2 solution. Strength of the SO2 solution is determined from milliliters of SO2 required to titrate 25 ml. of standard iodine solution (0.2 normal).
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING

Calcium content and pH of the brine should

be measured periodically {132).

Secondary Bleaching

Secondary oxidative bleaching may be desirable for better decolorization of dark-fleshed

cultivars of cherries such as 'Bing' and 'Windsor' and for the removal of browning caused

by blemishes {ISO).

Sodium hypochlorite plus acetic acid yields

snow-white cherries of good texture. Hydrogen

peroxide, 1-percent level and pH 11.5, for 15

to 20 hours at room temperature was found

satisfactory as a secondary bleach for SO2-

bleached 'Windsor' cherries.

Sodium chlorite at 0.75 percent and pH adjusted to 4.0 to 6.0 with 1.0 N acetic acid has

been found satisfactory for secondary bleaching of "Royal Ann" cherries, with no loss in

texture or development of off-flavors in the

finished product (5).

Defects

Definition of some terms commonly used is

necessary.

These are:

1. Soft cherries.—While a few soft cherries

may normally be expected from each batch,

severe softening of brined cherries has been

observed occasionally {72, 110, 119). This type

of softening has been attributed to a pectindegrading enzyme. The pectic substances in

the cherries are attacked by this enzyme during the brining storage period and then are so

badly degraded that they are no longer capable

of forming firm calcium pectate gels within

the cherries {H6, 1^8). Texture measurements enable the processor to follow the course

of the firming process. If the rate of increase

in firmness levels off too soon or the fruits

start to soften, the processor is alerted to take

corrective action.

Firmness of cherries may be checked with a

puncture gage similar to the one shown (fig.

63). It is a spring-push gage with a scale of

0-500 g. or 0-1,000 g. pressure, complete with

steel points of various sizes. To use the gage,

follow directions supplied by the manufacturer.

Test about 50 cherries from different parts of

PN-3120

FIGURE 63.—Texture tester, equipped with various

sizes of steel points.

each tank and average the results. An arbitrary

scale can be set up to show the relation between

gage readings and cherry firmness as determined by observations.

2. Mechanical Injury.—Any open pitter

hole, or holes measuring more than i/g inch

across in the aggregate; any pitter hole where

there is a material loss of flesh ; any pitter

tears; or any other mechanical injury that

materially affects the appearance of the cherry.

3. Surface Discoloration.—Any light surface
80 AGRICULTURE HANDBOOK NO. 442, U.S. DEFT. OF AGRICULTURE

discoloration exceeding in the aggregate Vs of

the surface of the cherry; any dark surface

discoloration exceeding in the aggregate the

area of a circle %6 inch in diameter, but not

exceeding in the aggregate Vs of the surface

of the cherry. Electronic color-sorting machines (fig. 64) are used to reject blemished

and unbleached cherries.

PN-3121

FIGURE 64.—Various types of electronic sorting

machines are used for color sorting of brined cherries.

This is a reflective measurement type, in which the

cherries are fed through a vibrating tray to a chute,

where they singulate by gravity. Three viewers, each

with a changeable standard background 120° apart,

compare the object in free fall. If a brined cherry has

an unbleached or blemished area, it is ejected by a

blast of compressed air signaled to occur 11/2 inches

after viewing.

4. Rain Cracks.—Any cracks in the stem

basin more than 14 inch in length, or outside

the stem basin more than %6 inch in length,

measured on the circumference.

5. Blemishes.—Insect injury, bird peck,

limb rub, hallmark, sunburn, solution crack,

or any other blemish or combination of

blemishes that materially affects the appearance of the cherry; also any cherry, the flesh

of which is materially discolored.

Sizes

The following sizes are considered as standards for all grades of brined cherries, except

for halved cherries:

1. Extra Small: 14 mm. to, and including,

16 mm.

2. Small: 16 mm. to, and including, 18 mm.

3. Medium: 18 mm. to, and including, 20

mm.

4. Large: 20 mm. to, and including, 22 mm.

5. Extra Large: Over 22 mm.

Mechanical size-graders (fig. 65) are used

to sort brined cherries into these size groups

rapidly.

Grades

Grade standards are described in "United

States Standards for Grades of Sulfured

Cherries", published in 1951 by U.S. Department of Agriculture, Agricultural Marketing

Service and reprinted in Federal Register

7954, Dec. 9, 1953. The producing States use

the Federal or slightly modified State grade

standards. The processer should be familiar

with all applicable grade standards for his

area and comply rigidly with them. In general,

these grades are separated as follows:

U.S. Grade A, or U.S. Fancy, consists of

properly matured cherries from similar cultivars that are clean, firm, well-formed, and

well-bleached. The cherries must be free from

defects caused by mechanical injury, surface

discoloration, rain cracks, blemishes, or other

means.

U.S. Grade B, or U.S. Choice, consists of

properly matured cherries from similar cultivars that are clean, fairly firm, well formed

and fairly well bleached. The cherries shall be
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 81

PN-3122

FIGURE 65.- -Size-grader. Brined cherries are graded for size over vibrating perforated screens. Graded cherries

are discharged through separate chutes.

free from serious defects caused by mechanical

injury, surface discoloration, rain cracks,

blemishes, or other means.

Most cherry briners do not separate grades

A and B, but offer a combination of the two

grades. The combination grade must have at

least 90 percent (by weight) of the cherries

reasonably well colored and free from misshapen fruit or blemishes, and at least 50 percent with good color and free from misshapen

fruit or blemishes.

U.S. Grade D, or "seconds", consists of cherries that are clean, but for other reasons fail

to qualify for U.S. Grade B.

MARASCHINO

After 4 to 6 weeks of storage, brined cherries

are ready for processing into maraschino cherries {60, 67). They are removed from the brine

and rinsed in water. The cherries are then pitted (fig. 66) and stemmed (fig. 67), although

in some instances stems are left on the cherries

intentionally. Unstemmed cherries are called

cocktail style. The pitted fruit is leached in

running water to remove the SO2. A rubber or

plastic tube is inserted to the bottom of the

container, and a stream of water is allowed to

flow through it for about 24 hours or until

the desired level of SO, is reached.
82 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

FIGURE 66.—Cherry pitter. Brined clierries are pitted before leaching. Cherries are seated in the rubber cups,

and the plungers remove pits one row at a time. This machine pits 700 pounds of large cherries and 400 pounds of

small cherries, with an average of 500 pounds, per hour.

The cherries are then dyed (19) with a food

dye such as erythrosine (known as FD&C Red

No. 3). Erythrosine is soluble at a pH of 4.5

or higher and precipitates in the tissue of fruit

at lower pH. This means that the color will not

leach out or "bleed" to color other fruits with

which the cherries may be used (l-í), in such

mixtures as canned fruit salad or cocktail. The

pH adjustment can be made with sodium bicarbonate to increase, and citric acid to decrease,

the pH. The cherries are boiled for about 20

minutes in a 0.025 to 0.050 percent erythrosine

solution of pH 4.5 or higher. Use enough solution to cover all the cherries. After cherries

and dye solution have cooled together for 24

hours, 0.25 to 0.50 percent citric acid by weight

is added to bring the pH of the solution to 4.2,

and the boiling and standing procedures are

repeated in order to set the dye. The cherries

are then rinsed in water to remove all dye

particles from the surface and pit cavities. The

dyed cherries are now boiled in a 30° Brix
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 83

sirup for 5 to 10 minutes, then are left to

stand for 24 hours, during which time the

sirup is absorbed. The sirup is removed by

draining, sugar is added to it to increase the

Brix reading to 40°, and imitation maraschino

cherry flavor is added. The sirup is returned

to the cherries, and the entire content is brought

to boihng, then is packed hot and sealed in

glass jars. Sodium benzoate, 0.1 percent or

less, may be used as a preservative, if necessary.

If the cherries are to be used with other

fruits, as in canned fruit salad or cocktail,

they are not siruped, but are sliced or quartered

after dyeing.

FD&C Red No. 4 (Ponceau SX) has been

used for coloring maraschino cherries for

some time. It has a brilliant red color with

unusual resistance to the destructive influences

of food ingredients and heat. Presently, the

FDA legal status for Red No. 4 is as follows:

"It may be used in food only for the coloring

of maraschino cherries at a level not to exceed

PN-3124

FIGURE 67.—Stem remover. While several types of stem removers are available, this one is widely used on brined

cherries. Rubber cups on the large rotating rollers hold cherries while the small rollers knock the stems off

the fruit. Cherries are then inspected on belts.
84 AGRICULTURE HANDBOOK NO. 442, U.S. DEFT. OF AGRICULTURE

150 parts per million by weight of the maraschino cherries. Such weight shall not include

packing media, or in the case of candied maraschino cherries, added sugar." Users of food

colors should consult with the FDA regarding

the current status of such colors, since regulations are changed frequently.

Ponceau is a soluble dye. It can be dissolved

in the sirup directly. A 30° Brix sirup containing 0.5 percent citric acid is prepared and

the desired amount of Ponceau added (note

FDA rule given previously). The bleached cherries are boiled with the sirup for 5 to 10

minutes and are left to stand for 24 hours.

After that, the same procedure described above

for erythrosine is followed.

A dye called Allura Red recently was approved by FDA for coloring maraschino cherries. This color is said to be sensitive to sulfur

dioxide residue in brined and leached cherries.

Likewise FDA should be consulted before this

dye is used.

The presence of artificial flavor, approved

color, citric acid, and sodium benzoate (if

used) must be declared on the label.

GLACE'

The manufacture of glacé cherries may be

considered as a continuation of the maraschino

process. Before the flavoring material is added,

the sirup buildup procedure is repeated on

succeeding days, with an increase of 10° Brix

each day until the sirup has reached approximately 72° Brix. Sucrose and dextrose (or

ctrn sirup) are used in equal weights to increase the sirup concentration. The cherries

are held in the 72° Brix sirup at least three

weeks for the sirup to penetrate into the cherries. Dextrose is used because it prevents the

cherries from becoming hard and granular

(123),

The cherries are then dried with a thin coat

of the sirup on them. Drying is done on screens

at 120° to 140° F., until the cherries are no

longer sticky.

Various modifications have been introduced

in the preparation of glacé cherries, mainly

to shorten the sirup-penetration process from

one day to a few hours. It is done by maintaining the sirup at 140° to 150° F. instead of

room temperature (S).

CANNING

Sweet cherries such as 'Napoleon', *Bing',

'Lambert', 'Van', and 'Black Republican' cultivars are canned without pitting (20). They

are, however, stemmed by hand or by mechanical Stemmers. Following the stemming, the

fruit is thoroughly washed (116),

The cherries are usually graded for the following sizes: 20/32 (16 mm.), 22/32 (17 mm.), 23/32

(18 mm.), 26/32 (20 mm.), 28/32 (22 mm.), and

33/32 (26 mm.) inch.

Cherries are canned in sirups ranging in

concentration from 0° to 35° Brix. They are

exhausted for about 10 minutes at 165° to 185°

F. Type L cans are used to eliminate corrosion

(71). Plain tin cans are often used for lightfleshed cultivars such as 'Napoleon' and

'Rainier'.

Filled and sealed cans are heated for 12 to

25 minutes at 212° F. The length of sterilization depends primarily on the size of the can:

For No. 303 cans, 12 minutes; No. 2 cans, 15

minutes; No. 21/2 cans, 18 minutes, and No. 10

cans, 25 minutes.

The standard of quality for canned cherries

is as follows:

(1) For pitted cherries, not more than 1 pit

is present in each 20 ounces of canned cherries ;

(2) For unpitted cherries, the weight of

each cherry in the container is not less than

Vio ounce;

(3) For unpitted cherries, the weight of

the largest cherry in the container is not more

than twice the weight of the smallest cherry

therein ;

(4) For unpitted cherries, the total weight

of pits is not more than 12 percent of the

weight of drained cherries ; and

(5) Not more than 15 percent by count of

the cherries in the container are blemished

with scab, hail injury, discoloration, scar tissue, or other abnormality. A unit showing

skin discoloration having an aggregate area

not exceeding that of a circle %& inch in diam-
SWEET CHERRIES: PRODUCTION, MARKETING, PROCESSING 85

ter and not extending into the fruit tissue

shall not be considered as blemished.

If the quality of canned cherries falls below

the standard prescribed above, the label shall

bear the general statement of substandard

quality.

FREEZING

While most frozen cherries are of the sour

cultivars, sweet cherries such as *Bing' and

'Black Republican' may be frozen for commercial distribution (56, 109).

The cherries are pitted and packed with 1

part of dry sugar to 3 to 4 parts of cherries.

Containers such as barrels, large friction-top

cans, large plastic bags in strong paper cartons,

are suitable for this purpose. Cherries should

be frozen quickly (150) and stored at 0° F.

or lower.

DEHYDRATING

Sweet cherries, being higher in soluble

solids content, may be blanched without collapsing as do the sour cultivars. Blanch the

washed and pitted cherries in steam for about

seven minutes at 180° to 200° F. before dehydration. Blancing will take the place of sulfuring ordinarily employed for sour cherries

(137).

Cherries are dehydrated on trays in tunnel

dehydrators with wet-bulb temperature maintained at 90° to 92° F. and dry-bulb 145° to

150° F. The drying time is from 18 to 27

hours, depending on tray load, air velocity,

and other factors involved in the construction

of the dehydrator (79). Sweet cherries should

be dried to a moisture level of 18 to 22 percent.

It is important to keep the trays clean to

prevent the dehydrated cherries from sticking.

PICKLING

Washed and pitted cherries may be pickled

with or without stems attached, by boiling

in a solution containing sugar, vinegar, and

spices such as cinnamon stick, allspice, mace,

clove, and ginger root. The amount of each

ingredients can be varied according to taste.

Recipes used for cucumber pickles may be

adapted for this purpose. Put whole spices in a

cloth bag to facilitate removal from the solution. Solubilized spice oils and extracts are also

available and may be used in place of whole

spices if desired. Pack boiling hot into jars

and let stand for about two weeks to become

well-blended before using.

OTHER USES

Although cherry juice, cider, and wine are

made from sour cherries such as the *Montmorency' cultivar, a blend of sweet and sour

cultivars will also produce a desirable product.

It is not necessary to remove the pits before

pressing for juice. The pit of cherries provides

a characteristic almond flavor, which is enjoyed by many, to the juice.

Cherry cider or wine is pressed from fruit

after fermentation. Straight sweet cherries do

not contribute the characteristic cherry flavor

and should be used only as a blend with sour

cherries for making wine (149).

LITERATURE CITED

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1965. SHORT STEM VIROSIS OF SWEET CHERRIES.

U.S. Dept. Agr., Plant Dis. Rptr. 49:

253-255.

(2) ANDERSON, H. W.

1956. DISEASES OF FRUIT CROPS. 501 pp. McGraw Hill, N.Y.

(3) ATKINSON, F. E., and STRACHAN, C. C.

1940. CANDYING OF FRUIT IN BRITISH COLUMBIA

WITH SPECIAL REFERENCE TO CHERRIES.

Fruit Prod. Jour. 20: 132-135, 166-169,

199-201, 229-232, 262-264, 310-312.

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G. C.

1964. EFFECTS OF N-DIMETHYL AMINO SUCCINAMIC ACID (B-NINE) ON VEGETATIVE AND

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Sei. Proc. 85: 11-16.

(5) BEAVERS, D. V., and C. H. PAYNE.

1969. SECONDARY BLEACHING OF BRINED CHERRIES WITH SODIUM CHLORITE. Food Tech.

23: 175-177.
86 AGRICULTURE HANDBOOK NO. 442, U.S. DEPT. OF AGRICULTURE

(6) BLANE, F. L., and KEIFER, H. H.

1955. THE CHERRY FRUIT FLY IN NORTH AMERICA.

Calif. State Dept. Agr. Bui. 44 (2) : 77-

78.

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BLODGETT, E. C.

1943. THE RASP LEAF OF SWEET CHERRY. Phytopathology 33: 620-622.

JENKINS, PHIL, and AICHELE, MURIT D.

1965. A SPUR TYPE GROWTH OF BING CHERRY

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BoDiNE, E. W., and NEWTON, J. W.

1942. THE RASP LEAF OF SWEET CHERRY. Phytopathology 32: 333-335.

BRADT, 0. A., RiCKETSON, C. L., and OTHERS.

1968. NEW FRUIT CULTIVARS FROM ONTARIO,

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BROOKS, R. M., and GRIGGS, W. H.

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and OLMO, H. P.

1972. REGISTER OF NEW FRUIT AND NUT VARIETIES. 2d ed. 708 pp. Univ. Calif Press,

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BUTLAND, P.

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CAMERON, H. R.

1962. MODE OF INFECTION OF SWEET CHERRY BY

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