PEST AND PESTICIDE MANAGEMENT

ON SOUTHERN FORESTS

USDA Forest Service

Southern Region

1720 Peachtree Road, NW

Atlanta, GA 30309-2417

The use of trade names in this publication is for reader

information and does not imply endorsement by the U.S. Department

of Agriculture of any product or service.

The United States Department of Agriculture (USDA) Forest Service is a diverse organization committed to equal opportunity

in employment and program delivery. USDA prohibits discrimination on the basis of race, color, national origin, sex, religion,

age, disability, political affiliation, and familial status. Persons believing they have been discriminated against should,contact

the Secretary, U.S. Department of Agriculture, Washington, DC 20250, or call 202-720-7327 (voice), or 202-720-1127 (TDD).

Management Bulletin R&MB 60 September 1994
Pesticide Precautionary Statement

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

Follow the directions and heed 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 them. 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 and in accordance with all applicable Federal, State and local laws.

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 U.S. Environmental Protection Agency, consult

your State forestry agency, county agricultural agent or State extension specialist to be sure the intended use is still registered.

ii
PREFACE

Federal law requires certification for all commercial pesticide applicators. The law also requires private applicator certification for the purchase or application of “restricted use” pesticides. The Environmental Protection Agency (EPA) has set minimum

competency standards for certification of pesticide

applicators. These standards include a practical

knowledge of pest identification, pest control, label

comprehension, pesticide laws, and environmental

considerations. The certification of applicators is

the responsibility of each individual State. To be

certified as a commercial forestry applicator, most

States require demonstrated competency in the general use of pesticides, with a specialization in forestry pesticides. This manual is a supplement, not a

substitute, to the general-use training material. That

material covers in detail the necessary information

on pesticide labels, general application, and safety.

This manual is intended to provide the information necessary to achieve specialized certification

for forestry pesticide applicators in the South. Additional certification may be required for other types

of application used in or near a forestry site, such

as aerial application and aquatic and right-of-way

weed control. The section on applicator safety has

been included for completeness, even though this is

thoroughly covered in the general category training

in most States. The materials provided here apply

mostly to southern pines, although hardwood culture is addressed. Emphasis is placed on herbicide

applications because most pesticides used in forestry are herbicides. Pesticide use in forest nurseries and seed orchards are not covered in detail

because of their special situations. Specialists in

nurseries and seed orchards receive special training

in proper pesticide applications for their needs.

This training manual was prepared by an ad hoc

committee appointed by the Southern Group of State

Foresters. The committee members are pesticide

specialists. Forest pesticide training manuals from

each of the southern States were reviewed and the

most pertinent sections were assembled along with

additional information and further edited to produce a draft document. Further review and comments by each of the State forestry agencies was

incorporated along with review by the Committee

members.

This manual contains information useful to forest pesticide applicators and should be a part of

their common knowledge if they are to be effective

and safe in their applications. The Committee recommends that the appropriate agencies in each State

carefully review this manual and incorporate appropriate sections in their training and reference materials. The Committee also recommends that testing

material for each State be periodically reviewed so

that applicators are tested on current methods and

information.

The Committee would thank the extension specialists whose works have been incorporated in this

regionwide compilation. Special recognition is owed

to Dr. James B. Armstrong, Department of Fisheries and Wildlife, Auburn University, for providing

the section on Vertebrate Animal Control. The editing of Christopher D. Kahle, Forest Pest Management, USDA Forest Service, Atlanta, GA, was crucial to the accomplishment of this task.

. . .

III
Committee Members

James H. Miller - Chairperson

Research Forester

Southern Forest Experiment Station

Auburn University, AL 36849-5426

Ken L. McNabb, Extension Forester

School of Forestry

Auburn University

Auburn University, AL 36849-5418

Brad Barber, Staff Forester Larry M. Bishop, Staff Specialist

Forest Resource Development Dept. Cooperative Forestry

Texas Forest Service USDA Forest Service

College Station, TX 77843-2136 Atlanta, GA 30367

Michael L. Thompson, Staff Forester

Department of Environment, Health

and Natural Resources

North Carolina Div. of Forest Resources

Raleigh, NC 27611

John W. Taylor, Jr., IPM Specialist

Forest Pest Management

USDA Forest Service

Atlanta, GA 30367
Table of Contents

Page

Preface ..................................................

Introduction ..............................................

The Forest Ecosystem and Stand Ecology .....................

Forest Types of the South .................................

Forest Pests .............................................

Principles of Forest Pest Management ..........................

Integrated Pest Management ................................

Pest Management Strategies ................................

Steps to Solving Pest Problems .............................

Forest Pesticides .........................................

Pesticide Resistance ......................................

Vegetation Control Using Herbicides ...........................

Weed Categories .........................................

Weed Control Treatments ..................................

Herbicide Application Terms ...............................

Application Methods ......................................

Ground Applications of Forestry Herbicides .....................

Woody Plant Control with Sprayers, Spotguns, and Injectors ......

Woody and Herbaceous Control with Granule Applications .......

Herbaceous Weed Control in Young Pine Plantations ............

Chemical Insect and Disease Control ...........................

Pine Bark Beetles ........................................

Pine Tip Moth ..........................................

Pine Sawflies ...........................................

Texas Leaf-cutting Ant ....................................

Pine Reproduction Weevils .................................

Gypsy Moth ............................................

Annosus Root Rot ................................ I ......

Forest Seed Orchards and Nurseries ............................

Seed Orchards ...........................................

. . . 111

1

1

2

4

9

9

9

10

1 1

1 3

1 3

1 8

2 0

2 3

2 3

2 4

2 4

2 5

2 5

2 5

2 6

2 7

2 7

3 7 Forest Nurseries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . &I
Table of Contents (continued)

Vertebrate Animal Control ...................................

Beaver .................................................

Deer ..................................................

Small Rodents ...........................................

Other Animal Pests .......................................

Record Keeping of Pesticide Treatments ........................

Applicator Safety ..........................................

The Pesticide Label ......................................

Mixing, Handling, and Applying Pesticides ....................

Pesticide Disposal, Storage, and Transport ....................

Spill Procedures .........................................

Pesticide Toxicity ........................................

Protecting the Environment ..................................

Off-site Application ......................................

Off-site Movement in Air ..................................

Off-site Movement in Water ................................

Other Environmental Considerations .........................

Endangered Species Act ...................................

Suggested Reading .........................................

Index ...................................................

Page

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43

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vi
INTRODUCTION

Society benefits greatly from the wise management of forest lands. The management objectives

for southern forests vary considerably across the

region, especially among ownerships. Management

practices used by public agencies are usually aimed

at balancing the outputs of wood production, wildlife, recreation, range, water, and mineral resources.

Intensive forest management practiced by forest

industry often attempts to optimize the production

of wood products while managing the other resources of wildlife and water quality. Private management of woodlots and tree farms provides a

source of income, recreation, and pride for many

individual landowners.

Foresters manage groups of trees that are relatively uniform in species composition, size, and

density called stands. Pests affect nearly every forest stand. Pests are plants, insects, diseases, or

animals that hinder management objectives, especially regeneration efforts. Pests can increase costs

of reforestation while reducing stand growth, product quality, and management efficiency. Pest outbreaks can mar the beauty of recreational forests,

hinder plantings for soil stabilization, and complicate research studies.

Modem pesticides offer an effective and safe way

to control many forest pests when used properly.

However, it is not always practical or cost effective

for a manager to use pesticides. Integrated pest

management is an approach that carefully considers

all management options, including pesticides, when

attempting to minimize losses from pests. It is

always beneficial to minimize pest impacts by wise

management strategies that enhance stand vigor and

by using pest-resistant growing stock. The effects

of any treatment on the overall health of the stand

and forest must be carefully considered.

Correct use of forest pesticides requires some

knowledge of the forest ecosystem, the biology of

forest pests, safe pest-control methods, and legal

constraints. It requires knowledge of the pesticides

and their application requirements. Safety of the

applicator, the public, and the environment must be

utmost in our considerations at all times.

The Forest Ecosystem

and Stand Ecology

A forest is a complex biological community composed of plants, animals, insects, and microorganisms. The populations of organisms combine in a

dynamic way with the environmental factors to form

a forest ecosystem. Forest ecosystems are driven

by the energy from sunlight. Only green plants are

capable of capturing solar energy and converting it

into sugars through the process of photosynthesis.

All animals, insects, and microorganisms in a forest ecosystem depend on the energy fixed by plants

from the sun.

The forest community and environmental factors

are linked together through natural cycles. The water

cycle - from rain, to soil, uptake through plants,

and out through surface and ground waters or leaf

transpiration - is powered by solar energy. The

water cycle also drives much of the nutrient cycle.

Nutrients are released into the soil when leaves,

branches, and tree trunks decay in the upper soil

zone, called the decomposition zone. Dissolved

nutrients from this zone then cycle back to the plants,

and are eventually returned to the soil in leaf and

stem fall or washed out of leaves by the rain.

Pesticides can also be washed by rainfall into the

decomposition zone, if they are not first broken

down by sunlight to other less toxic molecules while

on plant leaves. Ultraviolet light can break down

pesticide molecules. Like other organic molecules,

pesticides are also decomposed by microorganisms,

water, and chemical reactions. Some are bound to

soil particles until they decompose. Some more persistent pesticides may not fully decompose and may

be carried by water in the soil to streams or possibly groundwater, especially when misapplication

occurs. However, most pesticides are degraded to

basic harmless molecules through natural processes.

Within a forest ecosystem, all organisms compete for sunlight, energy, water, nutrients, and

space. The more of these resources that trees can

gain, the faster and healthier they can grow. The
structure of a forest ecosystem is arranged according to how the member organisms receive and use

these resources, mainly sunlight and water.

The natural change or maturing of a forest stand

over time is known as forest succession. Forest

succession begins with a major disturbance such as

a fire or windstorm or, in managed forests, with

harvesting (logging). These events create open areas

for development of pioneer plants. Pioneer plants

are those species that become established early in

succession. Most grasses and forbs, which collectively are called herbaceous plants, are good examples of pioneer plants. They require full or nearly

full sunlight to grow. Usually, they grow from

numerous seeds already present in the soil or from

seeds that have blown in with the wind. As forest

succession proceeds, most pioneer plants are slowly

shaded out by the developing forest.

Transitional species, usually comprised of lightdemanding conifers such as the southern yellow

pines, and hardwood species such as gums and

maple, become established after disturbance. Left

undisturbed: transitional species are slowly replaced

by shade-tolerant species that are longer lived. A

climax forest is one comprised of shade-tolerant

trees that can regenerate within their own shade.

Forest succession going to a climax forest is rarely

completed over large acreage of forest land. Man’s

intervention or periodic natural disturbances frequently short-circuit the successional process and

continuously “recycle” the forest to stands composed of transitional species. The expanses of southern pines are examples of the recycling of transitional species in the succession of a forest.

Forest managers work with natural succession to

optimize timber production, or create recreational

areas, or enhance wildlife habitat, or some other

management objective. Proper pesticide applications

can remedy certain unhealthy conditions in forest

stands and prevent the spread and damage from

insects and disease. However, because of the interrelationships within a forest community, controlling one component will influence others. Therefore,

the forest manager must consider all the effects of a

treatment when planning a control strategy to minimize undesirable effects.

Forest Types of the South

The South’s varied climate and site conditions

support a large number of tree species. There are

about 250 different native tree species. Almost half

are considered commercially important. The seven

major forest types in the South are shown in figure 1.

They are:

1. OAK-GUM-CYPRESS

2. OAK-PINE

3. OAK-HICKORY

4. LOBLOLLY-SHORTLEAF PINE

5 1 LONGLEAF-SLASH PINE

6. CEDAR

7. WHITE PINE-HEMLOCK

Pines are the most important commercial species.

Most forest industries depend on pine, but there is a

growing trend toward increasing use of hardwoods.

The four major species of southern pine are loblolly,

slash, shortleaf, and longleaf; all are classified as

southern yellow pines. Eastern white pine is a white,

soft pine of economic importance that is grown in

the southern mountains as well as in the North.

Baldcypress is another important conifer in the

South, but it is restricted to bottomlands, ponds, or

swamp areas of the Coastal Plain.

Oaks are the major commercial hardwood. Most

important are white oak, southern red oak, and

northern red oak. Yellow-poplar, sweetgum, blackgum, and water tupelo are important species used

in furniture and veneer manufacturing. Sycamore

and sweetgum are now being grown in plantations

for energy wood and pulp. The harvesting of hardwoods for use in manufacturing pulp products is

rapidly increasing, especially when the hardwoods

can be mixed with pine pulp.

2
Figure 1 .-Major Forest Types

Compiled by Forest Surveu Units of the

Southern and Southeastern Forest Eqwiment Stations.

1

OAK-GUM-CYPRESS: Botmm-land forests

in which 50 percent or more of the stand

wood, willow, ash, elm, hockbern/, and

maple.

PRODUCTIVE-RESERVED FOREST LAND:

Productive public forest land w,+hdrawn

from timber “tllilationthrough s+(l+u+e or

odminirtrotive regulation.
Forest Pests

In forestry, trees are considered to be the “crop. ”

Forest pests, therefore, are things that compete with,

injure, or spread disease to crop trees. The major

forest pests fall into four groups: weeds, insects,

diseases, and vertebrate animals.

Weeds

Weeds are any plants that interfere with land

management objectives. They can compete with

crop trees for limited moisture, nutrients, light, and

growing space. Survival and growth of crop trees

can be increased by effective control of weed competition, Other forest values, such as recreation and

wildlife habitat, can be enhanced with proper vegetation management. That is why herbicides are the

most commonly used pesticide in forests.

Insects

Forest trees are susceptible to insect attack at all

stages of growth and development, from seeds to

mature individuals. Although the majority of insect

species are beneficial to a forest’s health, some are

exceedingly harmful.

Outbreaks of insects that damage forests economically vary greatly in frequency, size, and duration.

Fortunately, most of these outbreaks are small,

short-lived, and usually consist of one or a few

spots in a stand or region. Others, however, may

expand until they encompass hundreds or thousands

of acres and may last for several years, as in the

case of southern pine beetle outbreaks.

Most insecticide applications in forest management are primarily used in seed orchards and forest

nurseries. Specialized applications are conducted

periodically to control pine tipmoths, leaf cutting

ants, gypsy moths, and southern pine beetles.

Diseases

Forest tree diseases include parasitic microorganisms, mainly fungi, bacteria, and plant rusts.

Most microorganisms in the forest are beneficial

and necessary for the functioning and health of the

stand or ecosystem. Microorganisms are vital to

nutrient cycling - they decompose leaves and

branches, which results in the release of nutrients.

Special fungi aid in nutrient uptake by tree roots,

while most nitrogen for forest growth is supplied

by bacteria living in the soil.

While most microorganisms are beneficial in

forests, many are harmful to trees. Parasitic diseases can attack trees in all stages of their life cycles

and cause poor health or even death. While some

forest tree diseases attack many tree species, others

target a particular species.

At this time, the only plant disease treated by

chemical applications in southern forestry is annosus

root rot.

Vertebrate Animals

Many kinds of animals can damage trees in the

South. Their damage may vary from insignificant

to very serious. Animal pests are deer, rabbits,

squirrels, beavers, and other rodents. Animal damage to tree seedlings usually occurs when natural

food sources are low and/or animal populations are

high.
PRINCIPLES OF FOREST PEST MANAGEMENT

Integrated Pest Management

Using a combination of prevention and control

methods is the best approach to pest problems. The

planned strategy of combining the best methods is

called integrated pest management @PM). Pest

management should be a part of an overall management plan for a forest area and the need for pest

control can usually be minimized through wise,

long-term, forest practices. The control method(s)

chosen will depend on the kind and amount of control necessary, balanced with costs and benefits

within legal, environmental, and other constraints.

The most important principle of pest control is to

use a control method only when it will prevent the

pest from causing more damage than is reasonable

to accept. Even though a pest is present, it may not

be necessary to control it. It could cost more to

control the pest than would have been lost because

of the pest’s presence.

Pest Management Strategies

The three main pest management strategies are:

1. Prevention - Keeping a pest from becoming a

problem.

2. Suppression (Control) - Reducing the pest

numbers or damage to an acceptable level.

3. Eradication - Destroying or removing a pest

completely from an area or geographic region.

Detection, through pest surveys, is an important

activity with all three strategies. Often these three

strategies are too costly so a fourth option - to live

with the pest problem - is adopted.

Pest Control Methods

Many pest control methods have been known

and used for years in agriculture, and are becoming

more common in forestry. The most important are:

Legal Control - Legal controls result from

Federal, State, or local laws and regulations. They

include such things as quarantines, inspections,

embargoes, and compulsory crop or product destruction.

Resistant Varieties - Trees grown from seed

from certain areas or from selected individuals can

be more resistant to certain diseases or be generally

healthier on specific sites. Healthier seedlings do

better at overcoming competition from weeds and

resist disease, insect, and animal attacks. For

example, tree breeding for resistance to fusiform

rust is currently underway.

Biological Control - Biological control uses the

natural parasites and predators of a pest to control

its numbers. For imported pests, this means the

careful introduction of parasites or predators from

the home country into the new range of the pest in

this country. Biological control can also be achieved

by increasing the numbers of native parasites. For

example, the control of the spread of gypsy moth is

being attacked by spraying a bacterium or virus that

specifically attacks the moth.

Cultural Control - Cultural practices that improve crop tree establishment and growth will often

minimize pest influences. These practices include

the use of only the best quality seeds and seedlings,

proper seedling care before and during planting,

planting patterns, timing of stand establishment,

and fertilization. For example, outbreaks of pales

weevil can be avoided by delaying replanting after

harvest.

Mechanical or Physical Control - Mechanical

treatments, such as chopping and shearing, are used

for woody weed suppression. Traps are sometimes

used for rats and voles.

Sanitation - Sanitation involves removing materials infected or infested by pests and the source of

food on which pests feed, such as the fell-andremove method for controlling the spread of southem pine beetles.

5
Prescribed Burning - Prescribed burning is

often used to help control undesirable forest species

and is often used in conjunction with other control

measures. Some pine stands are prescribe burned

on a regular basis to help control woody plant

competition. It is an important part of most chemical site-preparation treatments. This practice reduces

harvesting residues and thus improves planting

access. In other weed-control efforts such as kudzu

control treatments, prescribed fire is used to aid

applicator access and to reduce vegetation that

shields spray coverage. Prescribed burning also can

help reduce brown-spot needle blight in young

longleaf pine stands as well as annosus root rot.

Chemical Control (Pesticides) - Pesticides are

chemicals used to control, eradicate, or prevent damage by pests. Pesticides are tested and labeled for

specific pests, crops, and for specific land-use areas.

Steps to Solving Pest Problems

To solve pest problems, you should:

1. Correctly identify the pest(s).

2. Know what control methods are available.

3 _ Know and follow local, State, and Federal

regulations that apply to the situation.

4. Evaluate the benefits and risks of each method

or combination of methods.

5. Choose the methods that are effective yet will

cause the least harm to you and the environment.

6. Correctly apply the treatment method and document the application and results through proper

record keeping.

Pest control involves using all available methods

to keep pest populations below harmful levels, while

safeguarding the environment; and to recognize

when direct action, such as a pesticide application,

is necessary.

Forest Pesticides

Pesticides are used to regulate or disrupt plant

growth; control, attract, or repel insect pests; prevent and control disease infections; and control,

attract, and repel vertebrate animal pests. In southem forestry, herbicides are the most commonlyused pesticide. Insecticides are seldom used in general forest management because of high treatment

costs and because some pest insects are highly

mobile. The only disease-control treatment is employed for annosus root rot. Borax, applied to tree

stumps, keeps the disease from getting established

and spreading to the roots of nearby trees. Vertebrate animal control is often through trapping or

hunting but may employ repellants and poison baits.

Forest Pesticide Registration

All pesticides used in the United States must be

registered by the U.S. Environmental Protection

Agency (EPA) as specified in the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA)

and its amendments. Registration is either conditional or unconditional, based on data requirements

set forth in FIFRA. Before a pesticide can be used

operationally, data on the proposed uses must be

evaluated by EPA. To develop a pesticide product

and prepare it for registration under FIFRA, years

of extensive scientific testing must be performed on

the product’s chemical properties, human and environmental safety, and efficacy (effectiveness). For

forestry products, this may include testing under

field conditions using commercial application

equipment.

For wider testing of unregistered pesticides, EPA

can issue an Experimental Use Permit (EUP),

which establishes the limited conditions when an

unregistered pesticide may be transported, applied,

and disposed. Products subject to an EUP may only

be sold or distributed to participants in the test program and only according to conditions described in

the EUP.

Pesticides are registered by EPA as either general use or restricted use. A general-use pesticide

is one that will not cause adverse effects to the

environment when used for commonly recognized

6
practices in accordance with its label. Such pesticides are usually available to the public. Restricteduse pesticides require special procedures and training for applicators to prevent human exposure and

environmental damage. EPA limits the purchase

and use of restricted-use pesticides to certified

applicators. Some products may be used only by

certain categories of certified applicators. The label

will state clearly who may use the product. States

can also place general-use pesticides into the restricted-use category.

Another type of registration is commonly called

the Special Local Need (SLN) registration. Under

Section 24(c) of FIFRA, a State may register any

Federally-registered pesticide for a pest not listed

on the Federal label, provided that (1) registration

for such use has not previously been denied or canceled by EPA, and (2) a food tolerance (safe levels

in food), if required, has been established for the

proposed use. A “special local need” exists when

a State has an imminent pest problem for which an

appropriate Federally-registered product is not sufficiently available. The State registration for these

uses is deemed a Federal registration for purposes

of FIFRA, but distribution and application of the

product for these uses are confined to that State

only.

There is a provision in FIFRA for providing assistance when unexpected pest problems arise. Section 18 of FIFRA permits EPA to exempt Federal

or State agencies from FIFRA requirements when

emergency conditions exist. This provision permits

Federal and State agencies to respond quickly to

emergency pest conditions in their jurisdictions with

the use of pesticides not registered for the particular

site and pest.

Classes of Pesticides

Pesticides can be grouped according to their

chemical composition. The groups are:

l Inorganic Pesticides - These are made from

minerals. Minerals used most often are boron,

copper, sulfur, tin and zinc. Example: borate

for prevention of annosus root rot infestations.

l Synthetic Organic Pesticides - These are

synthesized pesticides that contain carbon, hydrogen, and other elements such as chlorine,

phosphorus, and nitrogen. Most herbicides and

insecticides in use are synthetic organic pestitides.

l Plant-derived Organic Pesticides - These are

made from plants or plant parts. Examples: pyrethrins from chrysanthemums for insect control

in forest nurseries.

l Living Microorganisms - These are viruses,

bacteria, and fungi produced by culture. Examples: the bacterium, Bacillus thuringiensis (B. t.),

and a virus, whose commercial formulation is

registered as Gypchek, are being aerially applied

as controls for the gypsy moth.

Pesticide Resistance

The ability of pests to resist poisoning is called

pesticide resistance. The possibility of resistance

must be considered when planning pest control programs that rely on the use of pesticides, especially

large insect control programs. Rarely does any pesticide kill all target pests. Each time a pesticide is

used, it selectively kills the most sensitive individuals. Some avoid the pesticide, while others withstand its effects. Pests that are not destroyed that

are resistant to the pesticide may pass the trait that

allowed them to survive to their offspring. At present, pesticide resistance is not an apparent problem

in forestry applications, however, it may become

one in the future.
VEGETATION CONTROL USING HERBICIDES

Weed Categories

Forest vegetation management is a term now

being used to describe the planned approach to controlling weeds as part of a forest management plan.

Weed species, or unwanted vegetation, can be

classed as weed trees, brush, vines, and herbaceous

weeds.

Weed Trees

Weed trees are hardwoods and conifers that interfere with management objectives or have other

unwanted qualities. They include deformed, defective, or undersized individuals and trees of undesirable species.

Brush

This is a term for unwanted woody growth that

includes shrubs and small trees. Brush prevents light

from reaching crop tree seedlings and deprives seedlings and even taller commercial species of water

and nutrients. Brush may interfere with commercial plantings and can create a habitat for rodents

that may damage tree seedlings.

Vines

Vines are plants with climbing or creeping stems,

including greenbriar, Japanese honeysuckle, wild

grapes, and kudzu. All of these grow very well on

many forest sites. They over-top trees, drag down

branches and crowns, and compete for light and

nutrients. Vines have vigorous sprouting habits and

are some of the most difficult weeds to control.

Herbaceous Weeds

Herbaceous weeds are grasses and broadleaf forbs

that retard seedling growth in new plantations and

natural stands, mainly through competition for

moisture. Seedlings may develop poorly or die,

especially during drought conditions. Herbaceous

weeds may also create favorable cover for treedamaging animals. They also increase the potential

for loss of a new plantation by wildfire. Herbaceous weed control is critical in forest nurseries,

seed orchards, and Christmas tree plantings. Herbaceous weeds can be grouped according to how long

they live - annual (1 year), biennial (2 years), and

perennial (for more than 2 years).

Weed Control Treatments

Nearly all vegetation control in forests has been

carried out in intensively managed pine forests and

along forest rights-of-way. Under development and

showing promise are single stem control methods

as well. Herbicides can be used in forest management for a number of specific purposes.

Site Preparation

When preparing to plant seedlings, it is often

necessary to reduce competing vegetation, reduce

debris, and form beds in poorly drained areas.

Mechanical methods for weed control, such as shearing and root raking, are expensive and often damage the site by displacing valuable topsoil and leaving the site vulnerable to erosion. By using herbicides for site preparation, applications are made in

the growing season before planting for competition

control, commonly followed by a prescribed burn

for debris reduction to increase planter access. Herbicides may be applied using either aerial or ground

application systems.

Herbaceous Weed Control

Research studies show that growth and sometimes survival of young pines and hardwoods can

be increased by controlling herbaceous weeds, usually in the first growing season following planting.

In addition, risk of fire can be decreased by an

effective weed control program. Care must be exercised when controlling herbaceous weeds because

tree seedlings can be damaged if label directions

are not followed carefully. Soil erosion may also

occur on susceptible soils with excessive control.

9
Crop Tree Release

When unwanted woody competition is not adequately controlled before planting, severe regrowth

can overtop young pines or desirable hardwoods

resulting in low crop tree survival or slowed growth.

Selective herbicides or selective applications are

used as release treatments to reduce brush (and herbaceous competition) without causing significant

damage to crop trees. Directed sprays, basal sprays,

soil spots, and injection treatments can also be used

to control target woody stems while missing the

crop.

Timber Stand Improvement (TSI)

In maturing stands, it is often profitable to eliminate low-value or cull trees that are competing with

more valuable trees. Single-stem control methods

may be used with injectors, spotguns, and sprays to

the basal bark and cut stumps. TSI treatments with

herbicides can also be used to prepare for regeneration of both pines and hardwoods in uneven-aged

management. These methods can also be used to

improve wildlife habitat by releasing mast and berryproducing trees and shrubs, as well as, creating

openings that provide edge habitat.

Herbicide Application Terms

Special terms describe how and when to apply

herbicides for use in forestry. They appear on labels

and in leaflets and bulletins. Understanding these

terms is very important to proper application.

Application Types

Terms that describe how to apply a pesticide

include:

Broadcast - Uniform application to an entire

area.

Band - Application to a strip or band over or

along each tree row.

Basal - Application to the lower portion of stems

or trunks.

Cut surface - Application to a cut or incision

in a tree or to a stump.

Directed - Aiming the herbicide at a specific

portion of a plant.

Foliar treatment - Application to the leaves of

plants.

Over-the-top - Application over the top of the

crop trees.

Soil application - Application to the soil rather

than to vegetation.

Soil incorporation - Application to the soil followed by tillage to mix the herbicide with the soil.

Spot treatment - Application to a small area

on the soil surface.

Stump treatment - Application to the top or

edges of a tree stump.

Stem injection - Application into incisions

around a tree stem.

Application rate -The application rate is the

specific amount of herbicide applied to a treated

acre or target stem.

Application Timing

Herbicides work best if applied when the target

plants are most susceptible or the crop trees are

most resistant to injury. Applying them too early or

too late reduces or even eliminates their effectiveness and may damage the crop. Terms that describe

when to apply herbicides include:

Preplant - Applied before the crop trees are

planted.

Preemergent - Applied before seedlings or

weeds begin to grow (emerge) in the spring. In

forestry, this term most often means applying the

herbicide after the trees are planted, but before the

weeds begin to grow, usually March to April.

10
Postemergent - Used after the crop trees or

weeds begin to grow (emerged).

Apply herbicides on woody plants only after all

woody plants have fully resprouted after harvesting,

burning, or mechanical treatments.

Application Methods

Herbicides are introduced into unwanted vegetation in several ways. They may enter through the

foliage, stem, or roots. Some can enter plants by

more than one pathway. The application method

for a herbicide is usually specified on the label.

However, unless the label specifies that it is illegal

to use a certain application method, any safe method

may be used. The best method will depend on the

situation, available equipment, and cost. Forestry

herbicides are applied by aerial and ground methods.

Ground methods will be covered in detail in the

next section. Most States require a separate training

and testing for aerial certification and so it Will only

be discussed briefly here. Contact your State forestry agency for more specific information.

Aerial Application

Aerial application of herbicides is common in

forestry because tract size is often large, access is

difficult, and the target vegetation is tall and dense.

Large acreage can be treated in less time and often

more economically by air. Both liquid and dry formulations are aerially applied. Specially designed

aerial spray equipment has been developed for herbicides that minimizes drift and achieves effective

coverage. Droplet size of aerially-applied liquid herbicides is larger than that used for insecticides,

although the effectiveness of foliar-absorbed herbicides may be reduced when large droplets are used.

Granular and pellet formulations of soil-active

materials are also applied aerially. Although less

subject to drift and weather conditions, uniform

distribution can be difficult with these materials.

Ground application methods can often supplement

and complement aerial application where more strict

control is required.

Mechanical Ground Application

Ground application by machine-mounted sprayers

and spreaders offers several advantages compared

to aerial methods. Machines can treat small areas

or large ones, provide banded or broadcast applications, and are less limited by weather conditions.

They are less visible than aircraft, so they are less

apt to arouse undue public concern. However, due

to terrain and stand conditions, ground machine

applications have definite limitations and are slower.

Crawlers, skidders, 4-wheel drive farm tractors,

and ATV’s (all-terrain-vehicles) can be used for

herbicide application. The machine used depends

on the job to be done, site conditions, and equipment availability. The application equipment

mounted on the machine must also be suitable

for the selected herbicide and stand conditions.

Broadcast-type sprayers must be able to cover a

sizable area efficiently and uniformly while being

very durable. For broadcast applications, boomless

cluster-nozzles and off-center nozzles can be

mounted up to 15 ft above the ground to reach tall

brush and can cover a swath of 40 to 50 ft. The use

of boomless nozzles has some limits. For example,

tall brush may mask a major portion of the spray

pattern. Also, the pattern of boomless nozzles is

not uniform across the swath. Spray coverage of

plants should be nearly complete, not just one-sided,

for effective control. Various “manifold” type

sprayers have also been designed for ground equipment as well as electrically-driven control droplet

application (CDA) systems.

An alternative to broadcast foliar application is

to broadcast soil-active, dry herbicides. These are

granules or pellets that can be applied before full

leaf growth masks the distribution. A specialized

blower system can distribute these materials in a

swath up to 80 ft wide. Fertilizer spreaders can be

used to treat short vegetation.

Herbaceous weeds are often controlled in bands

with farm tractors or ATV’s using spray booms.

One to three rows of seedlings can be sprayed per

pass. The up-and-down sway of the booms should

be minimized when treating two or more rows

because the rate can change greatly as the boom

ends change height.

1 1
Control systems are available for both sprayers Manual Ground Application

and spreaders to ensure that herbicides are applied

- .

at a consistent rate under varying ground speeds. Manual applications are herbicide treatments that

Maintaining the prescribed rate is critical for over- can be applied using backpack sprayers, spotguns,

the-top release applications. With or without con- and injection devices. Manual methods are used to

trol systems, calibration of machine application treat woody stems individually, apply granular herequipment is necessary on a regular basis to assure bicides for woody and herbaceous control, and to

accuracy of rate. Regular replacement of spray tips spray for herbaceous control in bands or spots.

is also required for applying accurate and uniform

rates.

1 2
GROUND APPLICATIONS OF FORESTRY HERBICIDES

Forestry applicators must be consistent to be

effective, and those who work for a commercial

applicator must be fast to be profitable. Consistency means mixing the correct herbicide accurately

time after time. It means using well-maintained

equipment with a steady effort.

Woody Plant Control with Sprayers,

Spotguns, and Injectors

The commonly applied manual treatments for

woody plant control are: (1) directed foliar sprays,

(2) basal sprays, (3) soil spots, (4) tree injection,

and (5) stump sprays. All sizes of trees and shrubs

can be controlled by using the right treatment when

the proper herbicide is applied at the correct time.

Here are the sizes of woody plants that can be

treated most effectively by hand methods:

Method

Effective size of

target stems

controlled

Directed foliar sprays up to 6 ft tall

Full basal sprays up to 6 inches d.b.h.*

Streamline basal sprays up to 2 inches d.b.h.

Soil spots by grid up to 10 inches d.b.h.

Basal soil spots all sizes

Stump sprays all sizes

Injection sizes greater than

1 inch d.b.h.

*d.b.h. is diameter at breast height, which is the stem diameter measured at 4.5 ft above the ground.

Directed Foliar Sprays

Directed foliar sprays are best used to release land 2-year-old pine stands when brush competition

is less than 6 ft tall. Caution must be taken to direct

the spray away from pine foliage and growing tips.

The benefits of release can be lost when herbicides

are misapplied to needles and shoots and too much

pine is damaged.

Equipment - Directed foliar sprays are usually

applied with a backpack sprayer and a spray wand

equipped with a full cone, flat fan, or adjustable

cone spray tip. Selection of a spray tip depends on

the applicator’s preference. Spray guns with narrow flat-fan tips are also used by some applicators.

Mixing - Accurate and thorough mixing is

needed to assure consistent control. A wetting agent

or penetrant can be added to the mixture to increase

control of all herbicides, and is a label requirement

for some herbicides. During windy conditions, a

drift control additive can reduce drift that damages

pines. Adding water-soluble dyes can help train

new applicators and also guide experienced applicaters .

Application Method - Apply the spray on the

target foliage and be sure to cover the growing tips,

but be careful to keep it off terminal shoots and

leaves of crop trees.

Basal Sprays

Full Basal - Full basal treatments require that

the lower 12 to 20 inches of target hardwood stems

be completely wetted on all sides with the spray

mixture. See figure 2. A backpack sprayer is used

with a wand or spray gun fitted with a narrow-angle

flat fan, cone, or adjustable tip. Herbicides are used

that are soluble in oil and mixed at percentages

specified on labeled products, usually less than 10

percent. Some are sold ready to use.

Streamline Basal - Streamline basal treatments

can control many woody plants including hardwoods

up to 2 inches d.b.h. Trees of susceptible species

up to 6 inches in diameter can be controlled. Treatment of small hardwoods less than 2 inches d.b.h.

results in the most control.

To apply this treatment, a backpack sprayer is

used with a spray gun and a low-flow (0.1-0.2

gallon per minute [gal/min]) straight-stream spray

13
tip. Also, a narrow-angle tip can be used, such as

15” and 0.1 gal/min. For controlling herbicide output to prevent waste, a pressure regulator is needed

to maintain pressure below 30 pounds per square

inch (lb/in2). At these pressures, an effective reach

of 9 ft is possible while bark splash is minimized.

Sprayers with diaphragm pumps will maintain about

30 lb/in2 with slow, steady pumping.

The most commonly used mixture for streamline

application includes the herbicide (3 to 20 percent),

a penetrant, and a carrier such as diesel fuel or

mineral oil. This mixture is clear when made correctly, but a white cloudy liquid or jell will form if

even a small amount of water is present. No amount

of water should be in the sprayer or mixing container. Make sure that all water has been drained

from the sprayer, the pump has been pumped dry,

and the sprayer has been rinsed and pumped with

diesel or mineral oil before filling with the mixture.

For treating stems that are less than 2 inches

d.b.h., apply the stream of spray up-and-down single stems for about 6 to 8 inches, or spray across

multiple stems creating a 2- to 3-inch-wide band.

Direct the spray stream at a point about 6 to 24

inches from the ground, to smooth juvenile bark.

Stems that are beyond the juvenile stage, thick

barked, or near 3 inches in diameter require treatment on both sides, unless they are susceptible

species. Back-and-forth bands can also be sprayed

on larger stems.

Applications are usually made in late winter and

early spring when leaves do not hinder spraying the

stem. The best application time will depend on the

herbicide, species, and location. Applications should

b e avoided in young pine plantations on hot days if

an ester formulation is used because pine injury

may occur from vapor drift.

Soil Spot Applications

Spots of soil-active herbicide are applied to the

soil surface in grid patterns or around target stems

for site preparation and pine release. See figure 3.

In this method, exact amounts of herbicide, specified in milliliters (mL), are applied to the soil surface at prescribed spacings. Thus the effectiveness

of the treatment depends on the applicator’s accuracy and consistency in amount applied and spacing.

The rate for soil spot application is determined

o n the basis of whether the treatment is for site

preparation or release, the texture of the soil, and

the susceptibility of the target species. Because of

possible pine damage, less herbicide is used for

release treatments. Less herbicide is also used on

Full Basal Streamline Basal

Figure 2.- Full basal method and streamline method of basal spray treatments for woody plant Control.

1 4
Basal Spots Grid Pattern

0

0

0

l

0

0

0

l

l

9

l

e

0

e

0

l

l

l

- g’-

0 l

l & 33

l l

l l

0 0

l e

l e

l

9

0

f

l

l

l

l

l

l

l

Figure 3.- Soil spot applications using basal spots and grid pattern.

sandy soils and more on clay soils. Seedling pines

can be severely damaged or killed, especially when

spots are placed too near.

Equipment - Spots are applied to the soil by

using a spotgun or a spray gun equipped with a

straight-stream spray tip. The spotgun delivers a set

amount while the spray-gun method requires training to judge the amount applied. Both can be connected to a backpack sprayer to carry the herbicide,

and the spotgun can also be connected to a backpack

or side-pack container. A spotgun consists of an

adjustable graduated cylinder or syringe that is operated by squeezing the handle. A forceful squeeze

can project spots up to 1.5 ft. A spray gun uses

pressure from the backpack sprayer to project spots

to over 20 ft, thus requiring less exertion.

Spotguns are available in metal and plastic

models. The more durable metal spotgun is for longterm use, while the plastic guns last for one area or

one season. Water should be pumped through the

spotgun after use, followed by a light oil for lubrication.

Calibration of spotgun - Spotguns are exactdelivery devices and thus either water or herbicide

can be used for calibration. By turning the adjustment screw, set the piston of the syringe on the

prescribed amount, for example, 2 mL. These graduations are not exact and must be checked. To do

this, squeeze the handle 10 times and collect the

solution in a container without splashing. Measure

the amount using a container graduated in milliliters.

For a 2-mL setting, it should deliver 20 mL after 10

squirts. If the total is more or less than the amount

expected, adjust accordingly and repeat the procedure until the exact calibration is achieved. Any

small error becomes large when thousands of spots

are applied per acre and can result in wasted herbicide and poor control or pine damage. Calibration

should be checked at least twice a day.

Spray gun for soil spot application - With

practice, an applicator can use a spray gun equipped

with a straight stream tip to apply l- to 3-mL spots.

The volume is determined by how long the handle

is held in the pulled position and the size of the

spray tip and pressure. A 0. l-gal/min (gallons per

minute) straight-stream tip is best for applying spots

of about 1 mL; a 0.2-gal/min tip for spots of about

2 mL; and a 0.3-gal/min tip for spots of about 3

mL. Although the spray gun is not an exact delivery device, accurate dosages can be applied with

practice and calibration.

Calibration of a spray gun and straight-stream

tip - The backpack sprayer is pumped to the pressure that will be maintained during application, 20

1 5
to 30 lb/in2. An appropriate tip is installed that

matches the prescribed spot volume. For spots of

uneven volume that are specified on the herbicide

label, a tip should be selected that is closest to the

prescribed volume. For example, a 0.2 gal/min tip

can be used to apply a 2.3 mL spot and so on. The

spray gun handle is pulled a few times while the

clicking sound is noted, which helps to judge the

rate of opening and closing of the handle. Using a

container that prevents splashing, the volume from

10 pulls of the handle is collected. This volume is

measured accurately using a container graduated in

milliliters. The volume should be 10 times the

desired volume per spot. For example, 10 pulls

from a 0.2-gal/min tip, with a consistent rhythm of

clicks, should give 20 mL. It takes practice to consistently apply the correct volume. Calibration

should be checked at least twice a day.

Application Method - Spots are applied to the

surface soil in grid patterns for treating areas or

immediately around selected target stems.

Spot Grid Applications - Prescriptions for spot

applications are usually specified by the volume

per spot and the spacing between spots. If the prescription is given only in quarts per acre, then the

volume per spot can be selected and the spacing

calculated. For example, if the prescription specifies 6 quarts per acre and 2 mL spots are chosen,

the number of spots per acre can be calculated by:

Number of Spots/acre = Qtiacre ’ 946 ml’qt

Number of ml/spot

= 6 X 946

___ = 2,838 spots/acre 2

Then to calculate the spacing between spots, the

area per spot must be determined:

Area/spot = 43,560 ft2/acre

2,838 spots/acre

= ,15.3 ft2, or 15 ft2

If the area around each spot is 15 ft2, then a 3 ft by

5 ft spacing would work. Natural walking strides

tend to match spacings of 3, 4, 5 and 6 ft, but

strides must be determined before beginning application.

Generally, a close-grid pattern is used when the

hardwood competition is small and a wider pattern

is used when hardwoods are larger. Thus, close

patterns are more commonly used for pine release

and the wider spacing for site preparation. For

example, to control mainly 6 to 8 inch d.b.h. trees,

a wide grid is preferred, such as a 6 X 6 ft, 5 X 6 ft

or 4 X 6 ft. To control thousands of small stems per

acre, the most common pattern is 3 X 3 ft.

Single Stem Application - Apply 2 to 4 mL of

undiluted herbicide for each 1 inch of d.b. h. The

higher rate is needed for most situations other than

sandy soils. Apply the spots on the soil within 3 ft

of the root collar of the unwanted tree. When more

than one spot is required per stem, the herbicide

must be evenly spaced around the stem. All small

stems of susceptible species that have roots in the

treated area also will be killed.

Tree Injection

Tree injection is the least costly method for killing hardwoods that are greater than 1 inch d.b.h.

This method can be used alone or in combination

with other individual stem treatments for site preparation, pine and hardwood release, timber stand

improvement, stand conversion, and creating cavity trees for nesting. This physically-demanding

method requires workers who can repeatedly and

precisely chop into tree trunks deep enough to properly deliver herbicide for uptake in the sap flow.

Frequent sharpening and maintenance of injection

tools is needed for best results.

Equipment - Common methods of tree injection use tubular tree injectors, hypo-hatchets, and

the hack-and-squirt method. See figure 4. Tubular

tree injectors consist of a long metal tube fitted

with a chisel-type blade that is used to cut through

the tree bark into the sapwood near the base of the

tree. The unit is equipped with a lever, handle, or

wire, which is pulled to deliver the herbicide (usually

1 mL) from the cylinder into the cut. The delivery

rate can be adjusted for accurate calibration. To

calibrate: fill and prime the injector; pull the handle

or wire 10 times while collecting the herbicide in a

container graduated in milliliters; if this is not 10

times the desired rate, adjust the lock-nut and repeat

the procedure until accurate calibration is achieved.

Frequent washings with water, including the pumping of water through the device, are the primary

1 6
Figure 4.-Tree injection using (A) tubular injector,

(B) hypo-hatchet, and (C) the hack-andsquirt method.

maintenance procedure. Commercial applicators

will want to carry spares for all rubber gaskets.

The hypo-hatchet consists of a hatchet with an

internal herbicide delivery system that is connected

by a hose to a herbicide container carried on the

belt. When the hatchet strikes a tree, the blade must

penetrate into the sapwood and the impact drives a

piston forward that delivers 1 mL of herbicide into

the cut. The rate cannot be adjusted. Daily cleaning

and lubrication of the impact piston is required

maintenance, along with periodic replacement of

rubber O-rings and seals. Safety glasses should

always be worn when using the hypo-hatchet because of frequent herbicide splashes. CAUTION:

All hoses and fittings should be checked daily for

leaks and appropriate repairs made to prevent applicator exposure.

Hack-and-squirt is a method that uses a narrowbit ax, hatchet, or machete along with a spray or

squeeze bottle or oiler can. The hatchet, ax, and

machete are used to cut into the sapwood, and the

herbicide is squirted into the cut. A grinder can be

used to narrow the bit of axes and hatchets for

easier and better cuts. Most commercial spray bottles are set to deliver 1 mL with each trigger pull,

but each one must be checked prior to use. Safety

glasses should also be worn when using this method.

Waist-high injections by the hypo-hatchet and

hack-and-squirt methods are just as effective and

fast to perform as basal injections. With larger

stems, more herbicide is applied by basal injections

because of the larger groundline diameter compared

to diameter at breast height.

Application Methods - The injection tool is

used to cut into the sapwood around target trees at

edge-to-edge spacings that are specified on the label.

The sapwood must be penetrated, which is difficult

on thick-bark species. Each cut must form a pocket

in which the herbicide is placed for uptake. Usually

1 mL of herbicide is applied to each cut. The herbicide should stay in the pocket and not seep out

through any split sides, because any herbicide on

the bark is wasted. When treating sprouting clumps,

each stem must be injected.

Stump Spraying

Stump resprouting of many species can be prevented by herbicide treatment. This can be an effec1 7
tive, low-cost treatment following harvest for site

preparation and after partial cuts for timber stand

improvement. Hand clearing treatments using saws

or axes for pine release can be enhanced by treating

the stumps with herbicide to prevent regrowth.

Equipment - A backpack sprayer is used that

has a wand or spray gun equipped with a straight

stream, fan, or hollow-cone nozzle. A sawyer can

carry herbicide in a utility spray bottle for treating

stumps after cutting. For small-diameter stumps, a

wick applicator can be used.

Application - Freshly cut stumps should be

treated as soon as possible after cutting. For stumps

over 3 inches in diameter, the outer edge, or cambial area, must be completely wetted with the herbicide. Smaller stumps are usually completely wetted.

To be successful, all small stumps should be treated.

Thus it is best that the sawyer or companion applicator treat soon after felling so no stumps are skipped.

Older, cut stumps can be treated with the streamline mixture. The mixture is applied to the outer 1

inch edge of the stump until runoff and to the base

of any sprouts.

Timing - Cutting and herbicide treatments can

be performed during late winter and summer. Winter treatments are slightly less effective than growingseason treatments. Stump treatments within 4 hours

of cutting have been shown effective - the sooner

the better.

Woody and Herbaceous Control

with Granule Applications

Hand-cranked broadcast spreaders can be used to

distribute granular or pelletized herbicides on small

tracts and areas with steep slopes or rough terrain.

They can be used where machine spreaders are not

suitable. Advantages of hand-operated spreaders are

that they are small, simple, inexpensive, and generally reliable hand tools. Unfortunately, uniform

application is often difficult to obtain and treatment

is slow and laborious.

Equipment

Granules and pellets are applied by hand-cranked

spreaders, air-blown backpack spreaders, and handbroadcast. Following are some basic facts about

each:

Hand-cranked Broadcast Spreaders

l Spread an adjustable swath from 6 to 30

ft wide.

l Production rates up to 2 acres/hour.

l Weighs 4 lb unloaded and can carry 20

lb of herbicide.

l Models include sack-type, plastic bag, or metal

and plastic hoppers.

l Spread is low and often blocked by trees

and weeds.

Backpack Mist Blowers Modified to be

Spreaders

l Increased individual productivity over handcranked spreaders.

l Treats a 30-ft-wide swath with fairly uniform

distribution.

l Production rates up to 2.5 acres/hour.

l Weighs 20 to 25 lb and can carry 30 lb of

pellets.

l High projection is possible for broadcast

granules.

Hand-broadcast and Grid Applications

l Useful for very small areas and for directed

or spot applications.

o Production rates up to 1 acre/hour.

l Backhand motions give a more even distribution than forehand applications.

l Large pellets are effectively applied in a grid

pattern.

l Less productive than the other two methods.

18
l High projection is possible for broadcast

granules.

The choice of method and equipment depends on

the amount of land an applicator intends to treat,

the terrain and stand conditions, and the anticipated

effectiveness of each method. Of these three

methods, hand-cranked broadcast spreaders present

the best combination of cost and efficiency to most

applicators and will be the focus here.

Hand Broadcast Spreaders

In general, hand-cranked spreaders are simple to

operate and easy to maintain. In the spreading

operation, pellets and granules fall by gravity

through an adjustable gate opening onto a handcranked spinning disc that throws the material 20 to

30 ft. Much of the mechanisms are the same on

many models, but several types of hoppers are available and each have certain advantages. See figure 5.

Sack-type hoppers with zippers do not spill when

accidentally tipped over on the ground or if the

applicator falls. However, sack-type spreaders require two people for loading because the sides tend

to collapse. Metal or plastic hoppers are the easiest

to load, but spills can occur when the applicator

trips or falls. Concentrated spills should be avoided.

This can be done by using spreaders with a closed

hopper. Also with any open hoppers, the applicator

is exposed to fine dust particles.

Calibration - A calibrated spreader is needed

to apply accurate rates. Calibrate the spreader by

using the specific herbicide to be applied or by

using blank granules and pellets when possible.

Calibration will require accurate weight measurements in the field using a small spring balance. The

calibration procedure is:

1. Adjust the gate opening (to a medium setting)

so that the herbicide granules pass freely from

the hopper onto the spinner disc.

2. Measure the width of the broadcast swath in

feet. This can be done on a road or in a parking

lot if blanks are used. Someone marks the outside edges of the swath while the operator cranks

the spreader and moves forward.

3. Put a known quantity of the granular herbicide

in the hopper (usually no more than 1 lb); make

sure the herbicide is not clumped. Blank product (pellets and granules without herbicide) can

be acquired from the manufacturer for this purpose.

4. Keeping a steady pace and constant cranking

motion, apply the known amount of product in

the treatment area. Walking speed must be the

same as the actual application. Measure the forward distance in feet that are required to apply

the known amount.

5. Calculate the pounds applied per acre.

Rate = 43,560 ft2/acre X lbs of test product

swath width (ft) X distance traveled (ft)

For example, the test swath was 16 ft wide and the

travel distance was 175 ft. One pound of product

was applied while turning the crank at a constant

rate. To determine the application rate:

Rate = 43,560 ft*/acre X 1 lb =

16 ft X 175 ft

15.6 lb/acre

6. Adjust the gate opening if the prescribed rate is

not achieved, and repeat the above procedure

until the desired rate is set.

Application - Spring applications are recommended, when rainfall is usually sufficient to activate the herbicide and vegetation is actively growing. Applicators should become familiar with the

site, its access and problem areas before making

the application. Aerial photographs and topographic

maps are particularly helpful for identifying sensitive areas such as streams and steep slopes. They

can also help plan the locations for application transects and access to flagging stations.

Establish transects or treatment swaths so that

they are equally spaced and parallel to each other.

This is necessary to achieve uniform herbicide

coverage. Flaggers are positioned at the ends of

each transect to guide the applicator, who is busy

keeping a proper pace and cranking speed. Transects can also be flagged before application, alternating the colors of flagging by transects.

1 9
.Figure 5.- (A) sack-type and (B) plastic hopper model of hand-cranked spreaders.

Herbaceous Weed Control in To apply banded treatments, the boom or spray

Young Pine Plantations wand is fitted with a wide-angle flat-fan tip, such

as 80” or llo”, with flow rates of about 0.2 to 0.3

Research has shown that herbaceous weeds are gal/min. A special flat fan tip that is “even” will

often much stronger competitors to pine seedlings increase control on the band edges, compared to a

than are hardwoods. Herbaceous weed control can regular flat fan that applies less herbicide on the

be accomplished using broadcast, band, or spot edges. Also, flood tips, due to their wide angles,

applications. Band applications are possible only are commonly used for banded applications.

when planting rows are well defined. Banded or Pressure regulation and a constant nozzle height

spot applications cost considerably less than broad- are needed to maintain uniform application rates.

cast treatments and only small losses in growth and Use a pressure of 5 to 15 lb/in* to give large dropsurvival have been observed with banded or spot lets with reduced drift. The low flow rates from

treatments relative to broadcast applications. low pressure operation also permit more acreage to

be covered per fill-up, adding to the efficiency of

Banded Applications the operation. Special “extended-range” or “lowpressure” tips are designed especially for lowBanded treatments are applied using backpack, pressure applications. A pressure regulator is necesATV, or tractor sprayers. Backpack sprayers treat sat-y to maintain low pressures with backpack sprayers.

one row at a time while machine sprayers can treat Some sprayers can be set at the desired pressure

two or more rows using a boom with spaced nozzles. while others rely on the installation of regulators in

Bands usually range from 3- to 6-ft wide. line or on the wand.

20
Many types of sprayers can be modified to apply

banded herbaceous weed control treatments in pine

plantations. One increasingly common machine is

a four-wheel ATV equipped with a sprayer. ATV

sprayers can be equipped with sprayer control systems with ground-speed sensing. The sprayer control system maintains a constant application rate

over a wide range of operating speeds. Protective

clothing and equipment like that used in motorcross racing should be worn when operating an

ATV sprayer in forestry conditions.

Calibration for Band Applications

Backpack Sprayers - The purpose of calibration is to determine the amount of solution that is

applied per acre within the band. By knowing the

amount of water sprayed per acre within the band,

the rate of herbicide prescribed per acre can be

added to that volume. Following is a calibration for

backpack banded treatment:

1. Install the appropriate spray tip.

2. Fill the spray unit half-full with water and pump

up the spray unit. Maintain the spray unit at

constant pressure during calibration and application.

3. Hold the wand at a height that produces the

desired band width.

4. Use the following table to determine the calibration distance required for the desired spray width.

Spray band Calibration

width distance

___---- ______ -j&t-------- ______

3 113

4 8 5

5 68

5. Measure the calibration distance on the ground

within the area to be treated. Treat this distance

at a walking speed you will use carrying a halffull sprayer and note the time.

6. For the amount of time noted from the above

step, collect spray from the nozzle(s) and measure in a container graduated in ounces.

7. The ounces collected happens to be equal to the

spray rate in gallons per acre.

8. If the total solution delivered per acre is not

adequate, or too much, adjust the pressure or

change tips and repeat steps 1 to 6.

9. Mix the desired rate of herbicide prescribed per

acre with the gallons of solution delivered per

acre.

EXAMPLE:

The measured spray width was 4 ft.

1. The calibration distance (see table) for a 4-ft

band is 85 ft.

2. Walking the 85 ft with a half-full spray required

28 seconds.

3. The nozzle sprayed 14 ounces in 28 seconds;

therefore, the sprayer is applying 14 gallons per

acre within the 4-ft band.

Machines - To calibrate a machine sprayer one

needs to know the same information including speed,

band width, and sprayer output. A step-by-step procedure for machine calibration is as follows:

1. Adjust the boom height to give the proper band

width and adjust the pressure. This height and

pressure should be maintained during calibration and application.

2. Using a throttle and gear setting that will be

maintained during application, measure in feet

the distance travelled in 1 minute. This should

be done on terrain similar to the treatment area.

3. Collect the spray volume from all nozzles for 1

minute and accurately measure this volume to

21
the nearest tenth of a gallon (fluid ounces X

0.0078 = gallons).

4. To calculate the portion of an acre treated in 1

minute, multiply the band width or sum of multiple-row band widths (measured in feet) by the

distance travelled in 1 minute. Divide by 43,560

square ft per acre. For example, one 3-ft band is

total gallons by the gallons per acre and multiply by the rate. Use these calcuations:

Amount of herbicide = total gallons x rate

to add to a tank gal per acre

=

200 gal x3oz=3ooz

20 gal per acre

sprayed at 145 ft per minute:

Thus, add 30 oz of herbicide to 200 gallons of

Portion of an acre water, to treat 10 acres at a rate of 3 oz per acre.

treated in = 3 x 145 = 0.01 acre Check the calibration when you start a new area,

1 minute 43,560 use a new rate, or when equipment has been repaired

or altered. With proper calibration of the equipment,

As another example, two 3-ft bands are being banded applications can begin.

treated by a boom sprayer at 145 ft per minute.

Thus, 6 ft of band width would be used in the

calculation and 0.02 acre was treated per minute.

Spot Applications for Herbaceous Weed

Control

5. To calculate the amount sprayed in the band,

per acre, divide the gallons sprayed in 1 minute

by the portion of an acre treated in 1 minute.

For example, 0.2 gal/min is collected and 0.01

acre was treated:

Gallons per =

0.2 gal/min

- 20 gal per

acre 0.01 acre - acre

This is the amount of spray solution being applied

to an acre within the bands.

6. Mix the per-acre rate of herbicide in proportion

to the gallons per acre of spray solution. For

example, if 3 oz of herbicide is the prescribed

rate per acre, then 3 oz of herbicide is added to

every 20 gallons of water in the mixing tank. To

mix 200 gallons of spray solution, divide the

Spot applications must be used when planting

rows are not well defined. Spot applications can be

made using the above banding procedure with some

change. Mainly, the sprayer is turned off between

seedlings as the applicator follows the rows. The

sprayer is turned on about 1.5 to 2.5 ft before the

seedling and shut off at the same distance past the

seedling. Thus the same tips, pressure, and calibration can be used. The applicator must still maintain

a constant walking speed while spraying each seedling if the rate is to be constant.

Full cone tips, with flow rates from 0.2 to 0.4

gal/min, can be used to apply circular, tree-centered

spots using a backpack sprayer or spotgun. However, full cone tips with these low flow rates produce very fine droplets that are easily blown by

wind. An adjustable cone nozzle produces large

droplets, but these droplets are too large to ensure

uniform coverage of preemergent herbicides.

2 2
CHEMICAL INSECT AND DISEASE CONTROL

,

Forest trees are susceptible to insect and disease

attack at all stages of growth and development.

Maintaining healthy and vigorous stands and individuals can lower the risk and incidence of insect

attack. However, uncontrollable soil, site, andweather

conditions preclude the elimination of diseases and

insects as a threat to forest trees. Only a few forest

insects and only one forest disease are treated chemically in the field for prevention or control.

Refer to the pesticide handbook of your State (if

available) or consult a local extension specialist for

a list of currently registered pesticides approved for

the following pests.

Pine Bark Beetles

Southern Pine Beetle

The southern pine beetle (SPB) (Dendroctonus

frontalis) is the most destructive forest insect in the

South. Weakening of trees by lightning, drought,

flooding, or windstorms may predispose otherwise

resistant or healthy trees to attack by SPB. Widespread subregional outbreaks occur every 5 to 10

years and last 1 to several years.

The SPB is a small, reddish-brown-to-black

beetle about l/8 inch long. The rear of the body is

rounded in contrast to the scooped-out posterior of

Ips beetles. The first indication of attack is usually

the yellowing or browning of needles. Small pitch

tubes (white, yellow, or reddish brown) about as

large as a small piece of popped popcorn (or a wad

of gum) are sometimes present on the trunk, starting

at a point about 3 feet from the bottom of the trunk

and continuing up into the lower one-third of the

crown. Under droughty conditions, pitch tubes may

be very small or even absent and only reddishbrown, boring dust will be present.

Adult beetles bore directly through the bark and

mate there. The females excavate S-shaped egg

galleries in the inner bark, which can be observed by

peeling off the outer bark. These galleries are different from the Y- and H-shaped galleries of Ips beetles.

White eggs are deposited in niches on either side of

these galleries and hatch into small, legless larvae in

4 to 9 days. The larvae mine for a short distance

23

before boring into the outer bark where they pupate.

The larvae are about l&inch long, white, and have

reddish-brown heads. The pupae are pure white and

about l/&inch long.

There are 3 to 7 generations per year, depending

on locality and weather. Soon after a tree is attacked,

all the needles usually turn yellow and then brown.

In addition to causing direct damage, SPB’s

introduce blue-stain fungi, which may clog the water-conducting tissues. Death may be hastened when

blue-stain fungi are introduced. The stain decreases

the value of the tree.

There are several alternatives to chemically controlling SPB infestations that can be used in appropriate circumstances. These include cut-and-leave,

pile-and-bum, andcut-and-remove. Cut-and-remove,

the preferred method, and pile-and-burn can be used

year-round; cut-and-leave should only be used during the summer. All require that a buffer strip of

green, uninfested trees be cut at the head of an active

SPB spot; professional help is recommended to best

implement any of these methods.

Ips Beetles

Ips beetles (Ips grandicollis, I. calligraphus, I.

amlsus, andI. pini) usually attack trees weakened by

natural or man-made causes, and often follow SPB’s.

They usually attack and kill only one or a few trees

in a given spot, but if conditions are satisfactory, they

may become edpidemic and destroy hundreds of

trees. Adults girdle trees quickly as they construct

their egg galleries in the inner bark. Death is usually

hastened by the introduction of blue-stain fungi,

which block the flow of sap and degrade the wood.

Ips beetles are yellowish, dark reddish-brown, or

black. They are l/8- to l/4-inch long. They are easily

recognized by the scooped indention of their posterior end which is surrounded by tooth-like projections. Pitch tubes on bark or branches, or the presence of boring dust, often indicate Ips attack. If the

tree is healthy, attack by Ips may not be successful

even though pitch tubes are present.

Fully grown larvae and pupae are yellowishwhite and range from l/8 to l/4 inch long. Gallery

patterns are more or less Y- or H-shaped. The eggs
are small andwhite. Eggs are laid in small egg niches

cut along the main tunnels. Upon hatching, larvae

feed, forming fine tunnels perpendicular to the egg

niche. Later feeding results in meandering tunnels,

usually filled with boring dust and frass. In hot

weather, it takes only 18 to 25 days to complete one

generation. Four or five generations occur each year.

Black Turpentine Beetle

Generally not considered a major forest pest, the

black turpentine beetle (BTB) (Dendroctonus

terebruns) can kill apparently healthy trees in a

stand. Attacks are increased by natural and mancaused stress, such as drought and logging damage

to trees and soil.

TheBTBisthelargestofthemajorsouthembark

beetles. It is l/4 inch or more in length and the rear

end is rounded. The color is reddish-brown to black.

Large pitch tubes (up to walnut size) are caused by

this insect. BTB’s attack the lower trunks of living

pines (from the base to 15 feet up, but generally in the

lower 8 feet). The beetle attacks fresh stumps and

livingtreesbyboringthroughthebarkandconstructing galleries on the face of the sapwood where eggs

are laid. Fifty to 200 eggs are laid in a group. They

hatch into white larvae, which feed on the inner bark.

BTB’s may girdle and kill trees when several

broods occur at about the same height. Generally, 10

to 25 percent of the infested trees die. The entire life

cycle takes 2-l/2 to 4 months, depending on temperature. Each year in the South there are usually two

full generations and part of a third.

Bark Beetle Chemical Control

Many trees newly attacked by BTB can be saved

by spraying from the baseup to the highest pitch tube

on the trunk with an approved insecticide.

If insecticides are used to control an active SPB

infestation, the following procedures are recommended. Fell all infested trees. Do not fell a buffer

strip of uninfested trees or vacated trees. Limb and

cut the felled trees into workable lengths. Using a

low-pressure sprayer, treat the entire bark surface

with an approved insecticide, turning the logs as

necessary.

Pine Tip Moth

The Nantucket pine tip moth (Rhyacioniu

fnrstruna) is common in the South. Its importance in

pine plantations and nurseries varies widely with

tree species, tree vigor, and environmental factors.

Heavily infested trees may be severely stunted or

deformed but are rarely killed. Generally, the tree

grows out of the susceptible stage within a few years.

All species of pines are attacked except white and

longleaf.

The adult moth is mixed gray and shiny copper

colored with a wingspan of about l/2 inch. The

young larvae are light cream colored; mature larvae

are light brown and about 3/8-inch long. Pupation

occurs in the damaged pine terminal.

Adults begin to emerge on warm days in late

winter or early spring and begin laying eggs within

a few days. Eggs are deposited on needles, stems,

developing tips, or buds. The larval period lasts 2 to

4 weeks. Several generations occur each year.

Tipmoth Chemical Control

Insecticide spraying for tipmoth is not generally

practiced, except in special cases such as progeny

tests, Christmas tree plantations, research study

plots, and some intensively managed pine plantations. Insecticide application must coincide with

moth emergence, which varies by location. Trapping insects can identify the times of emergence, and

spraying treatments planned accordingly.

Pine Sawflies

The redheaded pine sawfly (Neodiprion

Zecontei), blackheaded pine sawfly (N. excituns),

and loblolly pine sawfly (N. taedae linear-is) attack

most species of southern pines. All have caterpillarlike larvae that feed on pine needles and can defoliate seedlings and saplings. Usually they attacksingle

trees or small groups of trees; however, if conditions

are favorable, they may infest and defoliate thousands of acres of naturally regenerated or planted

pine. Repeated attacks on the same trees for 2 or

more years may kill them, but the main loss is in tree

growth. Sawflies are not economically important

2 4
pests of most forest stands, except in Florida where

insecticide treatment is necessary.

Pine Sawfly Chemical Control

Treatment is usually by aerial applicator for

large plantations or ground equipment for smaller

ones.

Texas Leaf-cutting Ant

Texas leafcutting ants (Attu texana), also known

as town ants, are destructive reproduction pests in

Texas and Louisiana. This ant can completely defoliate and girdle a small tree overnight. Such defoliation can be fatal to young pines. The ants strip the

needles and leaves from both pines and hardwoods

and use this plant material to culture a fungus that is

their only known food. Damage is most severe to

pines in the winter when there are no other green

plants. Pine reproduction can seldom become established where ants are present because they destroy

newly germinated or planted seedlings.

Texas leafcutting ants are rust-brown to dark

brown and differ greatly in size. Workers range from

l/16 to 1/2-&h long and have three pairs of prominent spines on the thorax. From April to June winged

males and females leave the colony on mating flights

and subsequently establish new nests. An ant nest

area, or “town,” is marked by many cone-shaped

mounds, usually 5 to 14 inches high and about 1 foot

in diameter. The town may cover an area from

several square feet to nearly 1 acre.

Texas Leaf-cutting Ant Chemical Control

Find and treat all nests in or near areas to be

planted. Scouting is easiest during fall and early

winter when the ants are active and their mounds are

not hidden by vegetation. A formulation of the fire

ant bait Amdro is registered for leaf-cutting ant

control. Fresh bait from a newly opened container

should be used for most effective control. Colonies

can also be eliminated by fumigating with methyl

bromide or carbon bisulfide. However, fumigating

should not be done near human dwellings.

Pine Reproduction Weevils

The pales weevil (Hylobiuspales) and the pitcheating weevil (Pachylobius picivom) are very destructive of first-year pine plantations growing on

recently cut-over sites. Weevils eat patches of bark

from the stem of a seedling and when these feeding

areas overlap, the seedling is girdled and dies. Both

weevils will feed and develop on all species of pine

within their range. Adults are oblong, black to reddish-brown, less than l/2 inch long. Winter is spent

as an adult or mature larvae in a chip cocoon constructed under the bark of a pine stump. In spring,

adults emerge and feed on the bark of saplings and

at the bases of seedlings.

The weevils feed at night and hide under debris

at the bases of seedlings during the day. Ifthe insects

are abundant, they may remove all the bark and

foliage, leaving only yellowish, pencil-like stubs.

Most damage occurs in spring and fall. The adults

are attracted to the odor of freshly cut pine stumps,

scorched pines, or dying trees and feed on the tender

bark of nearby seedlings. When these high-hazard

conditions (fresh stumps, scorched stems, etc.) occur, weevils may kill 90 percent or more of the pine

seedling in the reproduction areas; 30-60 percent

pine seedling mortality is not uncommon.

The most practical method of control is to delay

planting recently harvested areas for 9 to 12 months.

Pine Reproduction Weevil Chemical

Control

Infestations of pine reproduction weevils can be

prevented by dipping seedling roots in an insecticide/kaolin clay mixture, top dipping seedlings, or

over-the-top insecticide spraying.

Gypsy Moth

When it is present, the gypsy moth (Lymuntria

&spur) is one of the most damaging forest pests.

Females do not fly. This peculiarity probably accounts for the insect’s slow spread from established

infestations into new areas. (Note: In 1993 an Asian

strain of this moth was introduced in several loca25
tions on the eastern seaboard of the United States.

The females of this strain do fly and are expected to

severely impair future control efforts. However,

how bad the problem will be is not yet known. So,

the remainder of this discussion is limited to the

European strain of gypsy moth currently found in

the East.

The moths are harmless, but the caterpillars feed

on the leaves of forest, shade, ornamental, and fruit

trees as well as shrubs. A single defoliation can kill

some softwoods, tsvo or more defoliations can kill

many hardwoods. Large infestations involve millions of caterpillars and can degrade esthetic and

recreational values of forests, parks, and wooded

homesitesFew trees are killed outright by gypsy

moth defoliation, but many trees are weakened

and become susceptible to secondary attack by

other insects or plant diseases. During the last 80

years, parasites of this pest have been introduced

into infested areas. However, control of the gypsy

moth by its natural enemies has been less effective

than hoped.

Gypsy Moth Chemical Control

Aerial spraying with the insecticide dimlin

has been done in several southern States to control

gypsy moths and may be required in other States

as the moth migrates southward. The bacterium

Bacillus thuringiensis (B.t.) and avirus (Gypchek)

are being aerially applied to control gypsy moths.

Annosus Root Rot

In the South the only tree disease chemically

treated on an operational basis in the forest is

annosus root rot. It infects many pines and other

conifers. Infected trees grow slower and are more

susceptible to bark beetle attack than healthy

trees. Infected trees are also susceptible to spontaneous root failure and windthrow. The root rot

is caused by Heterobasidion annosum, a fungus

that grows in the duff at the base of potential host

trees. An example is shown on the front cover,

bottom inset photo. This fungus causes a white,

stringy, rot of the roots and occasionally the butts

of living trees. Eventually, the entire root system

may be destroyed. The fungus spreads by airborne spores that germinate on freshly cut stump

surfaces. Infections in plantations can usually be

traced to root contacts or grafts between healthy

and infected trees.

Infected trees have thin, light-green to yellow

crowns and short needles, tufted at the branch

end. Conks (the shelf-like fruiting structure of the

fungus) are not produced on most trees and are

often difficult to locate when they do appear

unless the duff layer is removed.

Trees tend to die in pockets, with trees in the

center dying first. In thinned pine plantations,

high-hazard sites can be 80+ percent infected.

High-hazard sites are well drained soils with at

least 65 percent sand in the upper 12 inches of soil

and a low water table.

Annosus Root Rot Chemical Protection

Sodium tetraborate (borax) is the most effective protection against stump surface colonization, residual tree infection, and mortality. Just

sprinkle borax or Borateen on a stump with a salt

shaker or any other shaker-type container. Sodium tetraborate will not prevent transmission of

H. annosum through root systems in already

infected stands. Such stands should be treated

with Phlebiu gigantea, a fungus that competes

naturally with H. unnosum. Thin the infected

trees in the summer.

26
FOREST SEED ORCHARDS AND NURSERIES

Seed Orchards

About 10,000 acres of forest tree seed orchards

in the South are intensively managed to produce the

seed required for artificial regeneration programs.

While these seed orchards represent a very small

area, their impact upon forest production in the

South is very large. In 1987, these seed orchards

produced enough seed to grow 1.3 billion seedlings

that were used to reforest 1.8 million acres of land.

This represented 85 percent of all reforestation

efforts in the South. A conservative estimate of

genetic gain for these seedlings is a lo-percent

increase in volume growth, which has a value of

$43.5 million ( 1990 figures). Additional value will

be created by improvements in form and disease

resistance.

Intensive management is critical to obtain the

required amount of seed from these orchards. Coneand seed-insect control programs are an integral

component of a seed orchard management program

because these insects can easily destroy more than

50 percent of the potential seed crop. In some cases,

losses to cone and seed insects have exceeded 90

percent of the potential seed crop. Additional control techniques, both biological and chemical, are

needed to ensure a continuing supply of geneticallyimproved seed for future reforestation efforts.

Chemical control is achieved by ground and aerial

application methods. Hydraulic sprayers, airblast

sprayers (mistblowers), and handheld compressedair sprayers are all used to control different species

of seed- and cone-insect pests. Aerial application is

increasing. Both helicopters and fixed-wing aircraft

are used to apply insecticides with either conventional or ultra-low volume equipment. The use of

aircraft has resulted in much less exposure to workers at seed orchards and reduced losses due to

insect damage.

Insecticides used in seed orchards range from

very toxic (azinphosmethyl) to very non-toxic (synthetic pyrethrins) to man and animals. Research for

safer insecticides is continuing.

Forest Nurseries

Forest tree nurseries are intensively-managed sites

that use considerable amounts of pesticides. Nurseries in the South grow about 80 percent of all the

bareroot stock produced in the United States. Lob1011~ and slash pine account for about 90 percent of

this production, although in recent years there has

been increasing interest in longleaf and sand pine,

as well as hardwoods. Most of the pesticide technology now used in forest nurseries was developed for

pine seedling cultivation.

Fumigants, herbicides, fungicides, and insecticides are used routinely to control a number of

major pests of tree seedlings. A number of pesticides have labels specific to tree-seedling nurseries.

The Environmental Protection Agency also allows

the use of pesticides labeled for horticultural nurseries to be applied in forest-tree nurseries. Individual States, however, may find exception to this

general policy.

Fumigants are used in nurseries to control pathogens and weeds. Weed control alone, however, does

not sufficiently justify fumigation as there are costeffective herbicides specifically labeled for use with

pine seedlings. On the other hand, pathogens can

be a serious problem so protection from various

damping-off fungi and other soilborne organisms is

considered a wise investment. Proper soil conditions are essential for effective fumigation.

Herbicides used in nurseries have been developed mainly for pine production. A number of effective compounds are labeled to control grasses and

broadleaf weeds in pine seedbeds. Herbicides are

usually applied over-the-top of the beds when weeds

first appear. Applications are repeated throughout

the growing season as deemed necessary. Weed

control in hardwood nurseries is more difficult. Not

only are fewer compounds labeled for weed control

in hardwoods, but herbicides are specific for hardwood species. If not properly matched, serious seedling damage can result. Herbicides are also used for

broad-spectrum weed control by spot treatment

around irrigation lines, roads, and buildings.

2 7
Fungicides are most often used in forest nurser- Insecticides are commonly used in nurseries.

ies to prevent and control fusiform rust. Fungicides Some of the more common insect pests are lesser

may also control damping-off during and immedi- cornstalk borers, spider mites, aphids, lygus bugs,

ately after seed germination. Several stem and foliar and white grubs. A number of insecticides are

diseases also periodically require use of fungicides. labeled for insect control in forest nurseries, although

Under nursery conditions of dense seedbeds, high the chemical must be matched with the pest for

fertilization, and irrigation, disease problems must maximum effectiveness.

be found and addressed quickly.

2 8
Many kinds of animals can damage live trees in

the South. Their damage may vary from insignificant to very serious. The mammalian pests - deer,

rabbits, squirrels, and other rodents - present the

most serious problems. With an animal-damage

situation, always check State and local regulations.

Due to their potential for greater economic impact,

beaver and deer will be discussed separately. Other

species may cause damage locally, but are not a

widespread or severe threat to trees.

Beaver

Beavers are capable of greatly altering their habitat to suit their needs. As they girdle and fell trees

to build a lodge and dam, standing timber often

becomes flooded and eventually dies. From a wildlife management standpoint, beaver ponds are very

beneficial; from a timber producer’s standpoint, beaver ponds may be costly.

Due to the sizeable beaver population in the

South, live-trapping and relocating offending animals is no longer a realistic control alternative.

There are no repellents, toxicants, or fumigants

registered for beaver control. Eliminating beaver

from an area requires a combination of trapping or

shooting, and destroying their dams. One of the

most effective traps for beaver is the 330 Conibear.

This trap, when properly set, kills the beaver instantly. When all the beavers have been trapped

from a pond, the dam can be destroyed and the

water drained from the flooded timber.

Deer

Deer, like beavers, have expanded in the South.

High populations, coupled with voracious feeding

habits, can badly damage newly established forests.

Deer prefer to browse on the leaves, stems and

buds of woody plants. They will browse on both

pine and hardwood seedlings. Browsing damage by

deer is easy to identify by the presence of the distinctive deer tracks and the characteristic pattern of

nipping the plant. Deer have no upper front teeth,

so they must tear off pieces of the plant, leaving a

jagged end. Bucks may also rub small pines with

their antlers during the rutting season. Damage

caused by antler rubbing appears as an area where

bark has been scraped off the tree trunk. Generally,

rubbing damage to young pines (up to 4 inches in

diameter) by rutting bucks does not present an economic threat except in high-value plantings such as

seed orchards and Christmas trees.

Deer are protected as game animals throughout

the region, but in cases of severe damage, it may be

possible to obtain a permit to shoot depredating

deer. Various scaring devices may be effective for

short periods, but deer soon become acclimated to

them. Repellents are short-lived and expensive. In

areas with many deer, seedlings can be treated with

a repellant and planted late in the season to extend

the effect. The most effective control measure may

be exclusion of deer from the area. This can be

accomplished by 8-foot high woven-wire fencing

or various configurations of electric fencing. Sport

hunting in the area may help control population

expansion.

Small Rodents

Cotton rats may feed on the roots, stems, and

leaves of seedlings. Cotton rats prefer dense cover;

therefore, keeping the area around the young trees

clean through herbaceous weed control will help to

reduce cotton rat problems. In small areas, cotton

rats may be excluded by using sheet metal fencing;

the bottom of the fence should be buried 6 inches in

the ground. Repellents, toxicants, and fumigants

are not effective in large-scale operations. The damage caused by this species is generally local.

Voles, small mouse-like animals with short tails,

may damage seedlings by girdling. They usually

have extensive systems of burrows and runways in

the ground litter. Trapping is not effective in largescale operations; however, some success may be

achieved with repellents and toxicants such as zinc

phosphide. Check local regulations before using

any chemical control measures. Voles rely on

vegetative ground litter for cover, so keep the area

around young trees clear of vegetation to help reduce

vole damage.

VERTEBRATE ANIMAL CONTROL

2 9
Pocket gophers are burrowing animals that eat

parts or entire root systems and expose roots so that

they dry out. Gophers can often be detected by the

presence of surface mounds. They are not usually a

pest in forest situations. However, damage can be

quite significant where pastures and old fields having sandy soils are machine planted to pine. Pocket

gophers can be controlled using baits containing

zinc phosphide .

Rabbits may damage young trees by girdling or

clipping off branches. Their damage may be distinguished from deer browsing by the smooth-angled

cut left at the end of the branch. Rabbit droppings

can usually be found in the damaged area. Like

deer, rabbits are game animals that are protected by

State regulations, but some States do allow exceptions in damage cases. Exclusion and trapping are

generally not effective for large-scale operations.

Some repellents containing thiram have proven

effective in discouraging rabbit browsing and

gnawing. Eliminating brush piles and other cover

may be useful in reducing high rabbit populations.

Biological control of rabbits, by encouraging the

presence of natural predators (hawks, owls, and

snakes) may help lower populations. Sport hunting

on an area can aid in population control.

3 0

Other Animal Pests

Fox squirrels may damage pines in the South by

eating cones, and by chewing pine bark. Fox squirrels are game animals and are covered by seasons

and other regulations. In isolated cases, squirrels

may be prevented from climbing individual trees

by installing a 2-foot-wide sheet of metal around

the trunk. For large-scale forestry operations, toxicants and repellents are usually not effective. Trapping or shooting can generally be used to eliminate

offending animals, but during peak years, new squirrels may soon move into the area to replace those

that were eliminated.

Feral hogs are descendants of free-ranging

domestic hogs or those released for sport hunting.

Feral hogs may damage young stands of timber by

rooting around the bases of trees. Large-scale fencing to exclude hogs is generally not practical, and

there are no toxicants registered for hogs. Livetrapping and removal during the spring and summer when acorns are scarce, and hunting during the

fall and winter may be effective in controlling feral

hog populations.
RECORD KEEPING OF PESTICIDE TREATMENTS

Keeping records of pesticide usage is required by

law. By Federal regulations, records for each application of “restricted use” pesticides must be kept

on file for at least 2 years. Records can establish

proof of proper use in damage suits, and they are

helpful in finding the cause of error if an error was

made. They can also provide information to trace

residue and damage problems. Such records can

also be helpful in liability cases.

Records can also help save money. They allow

comparison of results obtained from different pesticides, which can improve efficiency and reduce

pesticide misuse. Also, with careful records, winter inventories can be reduced by only buying the

amounts required.

The more information recorded, the more useful

the records will be. Carry a notebook to the application site and record all necessary and helpful information. Do not try to memorize all the necessary

items. A standard form can be used to ensure that

all necessary data is obtained. Following is a list of

the minimum information needed:

l Time of day and date of application

l Target pest(s)

l Equipment used

l Pesticide used:

- Common name

- Brand name

- Formulation and percent of active ingredient

- EPA registration numbers

- Establishment and lot numbers (in case of

cross-contamination or failure to control)

- Total formulation added to tank or hopper

- Amount of mixture used

- Acres treated

l Additional comments:

- Location

- Weather

- Applicator/crew chief/responsible individual

- Severity of infestation

On every record form there should be a space left

for ‘ ‘additional comments. ’ ’ Use this space to write

down information for your personal use. This information can be used to improve your business either

through better customer relations or by saving

money. Record-keeping requirements may vary by

State; check with the appropriate agency.

31
APPLICATOR SAFETY

The safety of forest pest applicators is assured

only if proper procedures are followed. The proper

procedures for handling, storing, transporting, and

applying pesticides are presented in this section.

This information is intended as a supplement to

other pesticide safety instructional materials.

The Pesticide Label

The single most important source of information

for safe pesticide use is the label. The label contains comprehensive information and instructions.

Look for precautionary statements and warnings

that are important in proper use. Detailed information appears for the application, storage, and disposal of the product. In addition, the label contains

a telephone number of expert advice during an emergency and address of the manufacturer. Information regarding the brand name, chemical name, type

of formulation, and EPA registration number are

also included. These items are important to a physician in case of an accidental poisoning. The most

important time in pesticide application is the time

spent reading and understanding the pesticide label!

Always read the label four times:

1. Before buying the pesticide.

2. Before preparing the material for use.

3. Before mixing and applying.

4. Before storing or disposing of the pesticide.

Before buying a pesticide, read the label to ensure

that the chemical is properly labeled for your particular job. Make sure that it is suitable for your equipment, conditions, and site. Before preparing the

chemical for use, read the label again for any warning or precautionary statements. Use all protective

equipment recommended.

The label also specifies rates, methods of application, and sometimes compatibility with other

chemicals or carriers such as diesel fuel. In addition,

the label gives the waiting period for crops and

entry by animals and any restrictions in the use of

the chemical.

Mixing, Handling, and Applying

Pesticides

The pesticide label contains precautionary statements, warnings, and often lists protective clothing

and equipment required when using that pesticide.

Read the label before mixing or applying.

Mixing

When handling a concentrated pesticide, precautions should always be taken. In their concentrated

form, many pesticides may cause skin irritation and

eye damage. Therefore, always use protective eye

wear and neoprene or rubber gloves when mixing

pesticides. Wear protective clothing such as longsleeved shirts, long pants, and water-resistant boots.

Be sure all skin abrasions or cuts are properly bandaged to prevent exposure before mixing chemicals.

On windy days, always pour pesticides by standing so that the wind comes from behind or from the

side - never pour upwind. Keep the container spout

below eye level. Small pumps can often be used to

transfer pesticide, minimizing the risk of exposure.

Applying

When applying pesticides, avoid unnecessary

exposure. Use protective clothing and equipment

specified on the label. Bring wash water and detergent to the field in clearly-marked containers. Before

application, use water to check equipment for leaks

and proper calibration. When applying a pesticide,

always stay upwind from the nozzle.

If pesticide is spilled on you, wash it off immediately. Also, take a change of clothes to the

application site in case your clothes become contaminated. Before eating and smoking, always wash

your hands and face thoroughly. Always wash contaminated clothes by themselves.

After application, clean and rinse the equipment.

The best area for cleaning is on a wash rack or a

concrete apron with a good sump. A second alterna33
tive is to apply the rinse water carefully on the site

where the pesticide was applied, in compliance with

the label.

When using pesticides, whether mixing, applying,

or rinsing equipment after use, always be certain

not to contaminate someone’s water supply. Several precautions can be taken to avoid these

problems. First, never apply near a well or other

water source. When possible, use a nurse tank to

mix only the pesticide needed for that day’s work

in the field. When filling from a well, use a separate pump equipped with check valves to prevent

back siphoning.

Pesticide Disposal, Storage,

and Transport

Disposal

After applying a pesticide, excess chemicals and

empty containers should be disposed of or stored

properly. Preventing pesticide surplus is the best

way to minimize disposal problems. Before buying,

make sure the pesticide is labeled for the intended

use. Carefully estimate the amount of pesticide

needed to complete the job and buy only what

is needed.

Check the site and be sure weather conditions

will allow proper application before mixing the

pesticide. Also, mix only what is needed for

that day.

Although steps can be taken to minimize any

excess chemicals, empty containers must always be

disposed of properly. After application, triple-rinse

all empty containers. Pour rinsate back into the

spray tank, not directly on the ground. Punch holes

in non-returnable containers so they cannot be used

again, and dispose of them in a sanitary landfill.

Returnable containers are to be returned.

Storage

Proper storage of pesticides is essential to their

safe use. The first step in proper storage is to designate an area where only pesticides are to be stored.

This area should be secured with a lock and prominently posted at each entrance: WARNING -

PESTICIDES - KEEP OUT. Ideally, the storage area should be made of fire-resistant materials,

including a concrete floor. The storage area should

be cool and dry and have an exhaust fan for proper

ventilation.

Never store pesticides near food, feed, seed, or

animals. Separate each type of chemical so that

herbicides, fungicides, and insecticides are stored

separately. Also, each formulation of pesticide

should be grouped separately. Always store containers so that labels can be clearly seen. It is also a

good practice to store containers off the ground on

pallets to avoid moisture problems. An up-to-date

inventory of all chemicals that are stored is recommended, including the date they were placed in

storage and the date they are used.

The storage area should be kept clean and orderly.

Absorptive clay, activated charcoal, pet litter, or

sawdust should be readily available at the storage

site to help clean any spill. A shovel, broom, and

dustpan should also be available, and always keep

a fire extinguisher in the area.

Transport

The following precautions can be helpful in safely

transporting pesticides:

l Be sure the containers are not damaged before

loading or during transport.

l Take only the amount needed for that day.

l Do not transport pesticides in the passenger section of a vehicle.

l Do not transport pesticides in the trunk of passenger cars or in trucks with wooden beds. Use a

trailer to transport pesticides when using a car.

l Secure all containers so they will not move during transport, using ropes and straps. During the

trip, check the containers periodically to be sure

they have not shifted and spilled.

l When at the application site, park the truck or

store the containers in the shade; direct sun can

cause the containers to overheat, resulting in

pressure build-up. A tarp can be used during

transport.

34
Spill Procedures

If an accident occurs during transport and a minor

spill results, administer first aid to anyone who

may have been injured. Confine the spill if it starts

to spread. Dig a dike around the area to contain the

spill. Always take a shovel when hauling pesticides.

Use an absorbent, such as those mentioned previously, to soak up the pesticide, or use clayey soil.

Dispose of the contaminated absorbent as you would

an excess pesticide.

Some accidents may result in a major spill - one

that endangers people, property, or the environment.

Your first priorities would be to administer first

aid, contain the spill if possible, and then call the

manufacturer. The number to call in case of an

accident is prominently displayed on every label.

The manufacturer will tell you which authorities to

notify and what action to take.

Pesticide Toxicity

Toxicity Terms and Definitions

Toxicity - The measure of the ability of a chemical to injure or kill.

Exposure - Coming into contact with a chemical

by swallowing, breathing or through contact with

the skin.

Hazard - The degree of exposure combined with

the level of toxicity.

LDSO - The amount (or lethal dosage) of a chemical required to kill 50 percent of the test animals.

Acute toxicity - A measure of the ability of a

chemical to injure or kill from one exposure.

Chronic toxicity - The ability of a substance to

injure or kill after long-term exposure.

Oral toxicity - The ability of a substance to injure

or kill if swallowed.

Dermal toxicity - The ability of a substance to

injure or kill if passed through unbroken skin.

PPM (parts per million) -A way to express the

amount of pesticide in water, plants, food, or animals (1 ppm is equal to about 1 oz in 62,500 lb or 1

tablespoon in 3,906 gal),

PPB (parts per billion) - Another expression of

the amount of pesticide in water, plants, food, or

animals that is 1,000 times LESS than a part per

million (1 ppb is equal to about 1 oz in 62,500,OOO

lb or 1 tablespoon in 3,906,OOO gal).

Half-life - The time required for one half of the

initial concentration of a chemical to be degraded.

Volatility - The ability of a liquid to evaporate.

Measuring Toxicity

Toxicity, the capacity of a substance to injure or

kill, varies with each chemical. Chemicals range

from extremely toxic to essentially nontoxic. However, large enough amounts of almost any substance

can be toxic. Knowing how toxicity tests are conducted is the key to understanding the toxicity of

pesticides. Test animals (mice, rats, or rabbits) are

fed a measured dose of a chemical. By increasing

the amount of a chemical fed to test animals, the

quantity required to kill 50 percent of the animals

can be determined (LD,,-J. This dosage is usually

referred to in terms of the weight of the chemical

and the weight of the test animal. For example, the

herbicide Roundup has an LD5e rating of 5,400

mg/kg. Approximately 1 pint of Roundup in the

concentrated form would have to be swallowed for

a 175-pound person to reach the LDsO dose.

Table 1 gives toxicity categories for pesticides,

and table 2 provides LD5e ratings for common

pesticides; other common substances that are frequently handled are listed for comparison. Table 3

provides estimates of the LD5a for a 175-pound

person for a range of substances. This information

implies that as the LD5c rating becomes larger, the

substance becomes less toxic. For example, Product A with an LD5e rating of 40 mg/kg is much

more toxic than Product B which has an LDsc rating of 4,000 mg/kg. Also note that many pesticides

have acute toxicity ratings that are lower than many

commonly used household compounds.

Many people wonder how a herbicide that successfully kills unwanted plants can have little toxic

effect on humans. Plants differ from humans in

many ways; researchers produce chemicals that

interrupt a plant’s function, but have little or no

effect on humans. For example, in the photosynthetic process plants produce their own food by

35
Table 1. Toxicity categories for pesticides

Toxicity Signal

category word

Acute

oral

L&o

Acute

dermal

L&o

Acute

inhalation

L&o

Eye effects

Estimated amount

Skin effects needed (orally) to

kill the average

person

I DANGER

(mgkd

<200

II WARNING 50-500 200-2.000

III CAUTION 500-5,000 2,000-20,000

IV CAUTION >5,000 >20,000

(m&z)

co.2 Corrosive; cornea1 Corrosive

opacity not reversible within 7 days

A taste (~7 drops)

to a teaspoonful

0.2-2.0 Cornea1 opacity Severe irritation

reversible within at 72 hours

7 days; irritation

persisting for 7 days

A teaspoonful to

an ounce

2.0-20 No cornea1 opacity; Moderate

irritation reversi- irritation at

ble within 7 days 72 hours

An ounce to a

pint

>20 No irritation Mild or slight

irritation at

72 hours

Greater than a

pint

> = Greater than.

< = Less than.

usihg carbon dioxide from the air, water from the similar way, resulting in the death of plants, but

soil, and sunlight. A chemical that blocks this pro- having no effect on people.

cess would kill a plant but may not affect humans Although the acute LDSO rating may indicate that

since people cannot photosynthesize. Other plant the compound is relatively low in toxicity, it is

processes, such as producing a particular amino wise to take precautions when mixing, handling, or

acid that only plants can make, can be altered in a applying any pesticides.

3 6

Table 3. Estimated acute oral and dermal toxicity’ (fluid ounces) of 18 chemicals for a

175-pound person

Trade name

Approximate Toxicity

acute oral LD,,’ category

Approximate

acute dermal LDsO1

(jl ounces) (jl ounces)

Nicotene

Methyl parathion (80%)3

Caffeine

Lindane (20%)3

Sevin (50%)

Aspirin

2,4-D

Malathion (91%)

Banvel

Garlon

Tordon 1013

Table salt

Banvel CST

Oust

Pronone iOG

Roundup

Tordon 101R

Velpar L

0.02 Extreme N/A

0.03 Extreme 1

0.21 Extreme N/A

2 Moderate 11

2 Moderate 3

3.5 Moderate N/A

3.7 Moderate 4

4 Moderate 1 2

7 Moderate 6

7 Moderate 11

8 Moderate 7

9 Moderate N/A

1 4 Slight 6

1 4 Slight 1 4

1 4 Slight N/A

15 Slight 1 4

1 8 Slight 1 1

2 0 Slight 1 5

N/A = Not applicable.

l The estimated toxicity for the pesticide is based on the formulated product (as in the container

before any additional mixing).

2 Most LDSO’s are expressed as a range, reflecting experimental conditions, type of carrier, species

of test animals, and precision of the tests, These estimates fall within the range and are only

projections based on animal tests.

3 Restricted-use pesticide.

38
PROTECTING THE ENVIRONMENT

Forest pesticides are registered only after the EPA

has sufficient information that their proper use will

not cause unreasonable harm to people or the environment, including wildlife and aquatic organisms.

Special concern is placed on environmentally sensitive areas that are in or around treatment areas.

These include streams, ponds, wells, special wildlife habitats, threatened and endangered species,

homesites, orchards, crops, and beehives. Special

precautions regarding such areas are often specified

on the label. Problems usually occur when applicators do not follow label directions or they apply

pesticides when conditions are not favorable. Damage to the environment usually is the result of one

of the following:

- Off-site application

- Off-site movement in air

- Off-site movement in water

- Pesticide persistence

Each applicator must be aware of these problems

and constantly work towards eliminating or minimizing adverse effects to the environment.

Off-site Application

To prevent off-site application or the accidental

treatment of environmentally sensitive areas, mark

boundaries clearly and use obvious, natural, or constructed features that can be readily identified by all

applicators. Set up buffer strips as specified on labels

and for protecting sensitive boundaries. Mark buffer

strips around streams and ponds and take special

care when treating sites near such areas. Every person doing the application should be informed and

made aware of boundaries and their identification,

as well as, any special precautions that should be

used. Ground guidance for both aerial and ground

application should be used whenever feasible to

help the applicator to remain in the target area and

make uniform applications.

Off-site Movement in Air

Chemicals may drift through the air from the

area of application and cause considerable injury if

they contact susceptible plants and animals, or sensitive humans. Movement through the air may result

from spray drift or volatility.

Spray drift is the movement of airborne spray

particles. The amount of spray drift depends upon

( 1) size of the droplets, (2) amount of wind, and (3)

height above the ground that the spray is released.

Droplet size depends mainly on pressure, design of

the nozzle, and surface tension of the spray solution.

In general, low pressures tend to produce large droplets and high pressures, small droplets. Small nozzle openings tend to produce small droplets and

solutions possessing low surface tension tend to

produce small droplets. To minimize drift, use the

largest nozzle opening and lowest pressure combination that is effective.

Volatility refers to the tendency of a chemical to

vaporize or give off fumes. The amount of fumes

or vapors given off is related to the vapor pressure

of the chemical and the temperature when applied.

High temperatures will increase volatilization. Vapor

drift is the movement of these vapors or fumes. The

vapors may damage susceptible crops, cause allergic reactions by sensitive humans, and may reduce

the effectiveness of the pesticide treatment due to

loss. Volatilization can occur when ester formulations of forestry pesticides are applied during high

temperatures. Formulations that are salts should be

used to stop volatile losses when the form of the

active ingredient is not important. Ester formulations should NOT be applied at high temperatures,

such as greater than 90”F, when crop injury or offsite

movement is a problem.

Granular materials, specialized spray equipment,

low-drift adjuvants, and other precautions can reduce

the chance of offsite movement. Select nonvolatile

pesticides when sensitive species are nearby.

39
Off-site Movement in Water

Pesticides can find their way into aquatic environments from areas that have been treated unless

proper precautions are followed. While pesticides

may be present in very dilute quantities, they tend

to be actively or passively magnified or concentrated by way of suspended particles that are dispersed in water.

Pesticides enter the aquatic environment by four

principal mechanisms:

l Point Source (e. g . , industrial effluents) -

Pesticide contamination of the aquatic environment by point sources such as industrial effluents may result in immediate biological catastrophes or in long-term adverse effects.

l Runoff - Pesticides can move off a treatment

area when dissolved in rainfall or on suspended

particles in surface drainage water as overland

flow (on compacted logging trails), stream

water, and in ditch water.

l Leaching - Ground water or subsurface water

may also be contaminated by pesticides. There

are examples of contamination of wells and

municipal water supplies.

l Spillage, Accidents, and Careless Handling

- Pesticides may also enter water courses

through inadvertent spillage (for example,

around industrial sites). Other ways pesticides

enter water include cleaning of application

equipment in streams and careless aerial application of pesticidal chemicals. Back-siphoning

into wells during loading should be prevented

by using proper procedures and back-siphoning

check valves.

The applicator must be knowledgeable of the factors that lead to runoff and leaching, while constantly guarding against spillage, accidents, and

careless handling.

Solubility

Because there are many different chemical compositions of pesticides, one might expect them to

vary considerably in the way they react with soil,

water, and other substances. Pesticides vary in their

potential for moving in soils and to groundwater.

Three major characteristics influence such movement: solubility, persistence, and soil characteristics.

The geology of the treatment area also influences

possible movement into groundwater.

Chemicals vary greatly in water solubility; the

greater the water solubility, the greater the potential for movement of the product to groundwater.

Pesticides with low water solubility have less tendency to both move off-site with storm runoff or

leach into the soil. More soluble compounds may

leach deeply enough through sandy soils to contaminate groundwater. Soil-applied pesticides may wash

or move into the water table more readily than foliarapplied materials.

Persistence

Although some chemicals degrade quickly, others breakdown slowly. The slowly degrading, or

“persistent’ ’ materials, are more likely to reach

groundwater over a period of time.

Soil Characteristics

Some chemicals become tightly attached

(“strongly adsorbed”) to soil particles and do not

move in the soil. Some are not so strongly adsorbed

and are more likely to move. Soil characteristics

are also important in the movement of chemicals.

Your local Soil Conservation Service office can

help you determine which types of soil are in your

area.

Three major soil characteristics affect chemical

movement:

1. Soil texture - This is an indication of the relative proportions of sand, silt, and clay in the

soil. Coarse, sandy soils generally allow water

and solutes to move rapidly downward and offer

few opportunities for adsorption. Finer-textured

soils generally allow water to move at much

slower rates and they contain more clay, silt,

and organic matter to which pesticides may be

adsorbed.

2. Soil permeability - A general measure of how

fast water can move downward in a particular

40
soil. The more permeable soils must be carefully managed to prevent any form of chemical

from reaching groundwater.

3. Soil organic matter - Influences how much

water the soil can hold before movement occurs.

Increasing organic matter will increase the waterholding capacity of the soil. Some pesticides

may also be adsorbed onto organic matter.

Geology

Distance of groundwater from the surface is

another important factor. If the groundwater is

within a few feet of the soil surface, pollutants are

more likely to reach it than if it occurs at greater

depths.

Permeability of geological layers between the

soil and ground water is also important. If surface

water can move quickly to the groundwater, the

potential for pollutants reaching groundwater is

increased.

Sinkholes - Especially troublesome. Surface

water often flows into sinkholes and disappears

quickly into the groundwater. If a chemical is applied to an area that drains to a sinkhole, even

moderate rain may carry some of the material directly to the groundwater.

Other Environmental Considerations

There are many species of beneficial forest insects, some of which are very abundant. Some feed

on forest debris and aid in its deterioration; others

feed on organic matter in the duff and soil and

contribute to improvements in soil fertility. Many

others are parasites or predators of destructive insects. Most are important food sources for birds

and other small animals. Bees and certain other

insects are important pollinators of some commercial crops as well as forest plants and trees.

Forest managers and pesticide applicators must

be aware of these and other wildlife members of the

forest environment. Pesticide labeling gives useful

information about toxicity to nontarget life forms.

Learn as much as possible about environmental hazards and potential nontarget impacts of pesticides.

Select the pesticide and application method that

will have the least adverse impact and still get the

job done.

Fish or wildlife kills in any area should be reported to the appropriate State agency. They may

want to investigate the reason for such a kill to help

prevent future occurrences. Many factors other than

pesticides can kill fish or wildlife.

Endangered Species Act

The Endangered Species Act provides:

l Legal protection for endangered and threatened

species.

l That all federal agencies (EPA and USDA Forest

Service, for example) ensure agency actions will

not jeopardize the existence of any endangered

species.

About 58 endangered species (17 percent of the

current endangered species) live in forests in the

United States. About 24 pesticides presently labeled

for use in forests are considered to have an adverse

effect on one or more of these endangered species.

These numbers doubtless will change over time,

but are given only to indicate that many endangered

species live in forest habitats - and a number of

pesticides will affect them. Every affected pesticide sold since 1988 shall have a warning on the

label which prohibits pesticide use in the range

(occupied habitat) of endangered species. Each State

will have an enforcement plan to implement the

Endangered Species Act in the near future. Consult

with a county extension agent for the current

regulations.

41
SUGGESTED READING LIST

American Farm Bureau Federation. 1987. Protecting our groundwater: a grower’s guide. Park

Ridge, IL: American Farm Bureau Federation.

8 P.

American Pulpwood Association. 1985. Guidelines

for effective and safe aerial application of herbicides. American Pulpwood Association, Inc.,

Forest Management Committees, Southeast

Technical Division, Southwest Technical Division. 23 p.

Baker, Whiteford L. 1972. Eastern forest insects.

Miscellaneous Publication No. 1175. Washington: U. S . Department of Agriculture.

642 p.

Cantrell, Rick L., ed. 1985. A guide to silvicultural herbicide use in the southern United States.

Auburn, AL: Auburn University School of

Forestry, Auburn, AL. 500 p.

Clemson University. 1984. Herbicides, prescription and application, proceedings fourth annual

forestry forum, 1984 March 21, Clemson University, Department of Forestry. Clemson, SC:

Clemson University. 65 p.

Ebel, Bernard H.; Flavell, Thomas H.; Drake, Lloyd

E.; Yates, Harry 0. III; DeBarr, Gary L. 1975.

Southern pine seed and cone insects. Gen. Tech.

Rep. SE-8. Asheville, NC: U.S. Department

of Agriculture, Forest Service, Southeastern

Forest Experiment Station. 40 p.

McNabb, Ken. 1991. Forest herbicides are environmentally safe. Forest Farmer. 50(3): 16-18.

Miller, James H.; Mitchell, Robert J., eds. Rev.

1990. A manual on ground applications of forestry herbicides. Management Bulletin R8-MB

21. Atlanta: U.S. Department of Agriculture,

Forest Service, Southern Region. 389 p.

Miller, James H.; True, Ronald E. 1986. Herbicide

tests for kudzu eradication. Georgia Forest

Research Paper 65. Macon, GA: Georgia Forestry Commission. 11 p.

Near-y, Daniel G.; Flinchum, D. Mitchell; Cantrell,

Rick L. 1984. Safety with forest pesticides.

Forest Farmer. 43(5):16-18.

Newton, Michael. 1976. Apply pesticides correctly,

a guide for commercial applicators, Forest pest

control. Report No. EPA/540/8-761023. Washington: U . S . Environmental Protection Agency.

14 p.

Singer, James. Rev. 1982. Pesticide safety guidelines for personal protection. USDA Forest

Service, FPM 83-l. Davis, CA: U.S. Department of Agriculture, Forest Service, Forest Pest

Management. 45 p.

Southern Forest Products Association. 1983. The

safe use of herbicides: A brief summary of information presented in the herbicide safety workshop program. New Orleans: Southern Forest

Products Association. 7 p.

Thatcher, Robert C.; Searcy, Janet L.; Coster, Jack

E. ; Hertel, Gerard D. 1980. The southern pine

beetle. Technical Bulletin 163 1. Washington:

U.S. Department of Agriculture. 266 p.

Timm, Robert M., ed. 1983. Prevention and control of wildlife damage. Lincoln, NE: University of Nebraska, Cooperative Extension

Service. 661 p.

4 3
INDEX

Acute toxicity, 35.

Aerial application, 11.

Annosus root rot, 26.

Annosus root rot chemicial protection, 26.

Application rate, 10.

Application timing, 10.

Application types, 10.

Applying pesticides, 33.

Bald cypress, 2.

Banded applications, 20.

Bark beetle chemical control, 24.

Basal soil spots, 13.

Basal sprays, 13.

Beaver, 29.

Biological control, 5.

Black turpentine beetle, 24.

Broadcast, 10.

Brush, 9.

Calibration for band applications, 2 1.

Cedar, 2.

Chemical control, 6.

Chronic toxicity, 35.

Climax forest, 2.

Cotton rat, 29.

Crop tree release, 10.

Cultural control, 5.

Cypress, bald, 2.

Decomposition zone, 1.

Deer, 29.

Dermal toxicity, 35.

Directed foliar sprays, 13.

Diseases, 4.

Disposal of pesticides, 34.

Endangered Species Act, 41.

Environmental considerations, 4 1.

Experimental Use Permit, 6.

Exposure to pesticides, 35.

Forest, 1.

Forest ecosystem, 1.

Forest nurseries, 27.

Forest pests, 4.

Forest succession, 2.

Forest types, 2.

Fox squirrels, 30.

Full basal sprays, 13.

General-use pesticide, 6, 7.

Geology, 41.

Granule applications, 18.

Gum, 2.

Gypsy moth, 25.

Gypsy moth chemical control, 26.

Half-life, 35.

Hand broadcast spreaders, 19.

Hazard, 35.

Hemlock, 2.

Herbaceous weeds, 20.

Herbaceous weed control, 9, 20.

Hickory, 2.

Hogs, feral, 30.

Injection, 13.

Inorganic pesticides, 7.

Ips beetle, 23.

Insects, 4.

Integrated pest management, 1, 5.

LD5a, 35.

Legal control, 5.

Living microorganizms, 7.

Manual ground application, 12.

Mechanical ground application, 11.

Mechanical or physical control, 5.

Mixing pesticides, 33.

oak, 2.

Federal Insecticide, Fungicide, and Rodenticide Pales weevil, 25.

Act, 6. Parts per billion (p.p.b.), 35.

Foliar sprays, directed, 13. Parts per million (p.p.m.), 35.

4 5
Persistence, 40.

Pests, forest, 1.

Pest management strategies, 5.

Pesticides, 6.

Pesticides, disposal of, 34.

Pesticides, exposure to, 35,

Pesticides, general use, 6,

Pesticides, inorganic, 7.

Pesticide label, 33.

Pesticide mixing, 33.

Pesticide resistance, 7.

Pesticide toxicity, 35.

Physical control, 5.

Pine

loblolly , 2.

longleaf, 2.

shortleaf, 2.

slash, 2.

white, 2.

Pine bark beetle, 23.

Pine reproduction weevils, 25; chemical control

of, 25.

Pine sawfly, 24; chemical control of, 25.

Pine tip moth, 24.

Pioneer plants, 2.

Pitch-eating weevil, 25.

Plant-derived organic pesticides, 7.

Pocket gopher, 30.

p.p.b. (part per billion), 35.

p.p.m. (parts per million), 35.

Postemergent, 11.

Preemergent, 10.

Preplant, 10.

Prescribed burning, 6.

Rabbits, 30.

Rat, cotton, 29.

Resistant varieties, 5.

Restricted-use pesticide, 7.

Rodents, small, 29.

Sanitation, 5.

Seed orchards, 27.

Sinkholes, 41.

Site preparation, 9. I

Soil organic matter, 41.

Soil permeability, 41.

Soil spot application, 14.

Soil spots by grid, 16.

Soil texture, 14, 40.

Solubility, 40.

Southern pine beetle, 23.

Special Local Needs (SLN) registration, 7.

Spill procedures, 35.

Spot applications for herbaceous weed control, 22.

Spotguns, 15.

Sprays, directed foliar, 13.

Squirrels, fox, 30.

Stands, forest, 1.

Storage of pesticides, 34.

Stream line basal sprays, 13.

Stump sprays, 13, 17.

Synthetic organic pesticide, 7.

Texas leaf-cutting ant, 25; chemical control of, 25.

Timber stand improvement, 10.

Timing of applications, 10.

Tipmoth chemical control, 24.

Toxicity, 35; dermal, 35; categories, 36.

Transitional species, 2.

Transport of pesticides, 34.

Tree injection, 16.

Vertebrate animals, 4; control of, 29.

Vines, 9.

Volatility, 35, 39.

Vole, 29.

Weeds, 4; categories, 9.

Weed trees, 9.

Weevil, pales, 25.

4 6