Pest

Management

Early detection and treatment

of pests means a healthier

growing environment.

In your backyard

Pest management can be one of the

greatest challenges to the home gardener.Yard pests include weeds,

insects, diseases, and some species of

wildlife.Weeds are plants that are

growing out of place. Insect pests

include an enormous number of

species from tiny thrips, that are

nearly invisible to the naked eye, to

the large larvae of the tomato hornworm. Diseases are caused by fungi,

bacteria, viruses, and other organisms, some of which are only now

being classified. Poor plant nutrition

and misuse of pesticides also can

cause injury to plants. Slugs, mites,

and many species of wildlife such as

rabbits, deer, and crows can be

extremely destructive.

Identify the

problem

Careful identification of the problem

is essential before control practices

can be used. Some insect damage

may appear to be a disease, especially if no visible insects are present.

Nutrient problems may also mimic

diseases. Herbicide damage resulting

from misapplication of chemicals

also can be mistaken for other problems.

What to look for

Insects and mites

All insects have six legs, but other

than that they are extremely variable.They include such organisms as

beetles, flies, bees, ants, moths, and

butterflies. Mites and spiders have

eight legs– they are not insects. But

for the purposes of this tip sheet,

they will be considered as insects.

is a cooperative project of:

USDA Natural Resources

Conservation Service

National Association of

Conservation Districts

Wildlife Habitat Council

April 1998

The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national

origin, gender, religion, age, disability, political beliefs, sexual orientation, and marital or family status. (Not all prohibited bases apply to

all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print,

audiotape, etc.) should contact USDA’s TARGET Center at 202-720-2600 (voice and TDD). To file a complaint of discrimination, write

USDA, Director, Office of Civil Rights, Room 326W, Whitten Building, 14th and Independence Avenue, SW, Washington, DC 20250-

9410 or call (202) 720-5964 (voice or TDD). USDA is an equal opportunity provider and employer. 

One in a series of 10 tip sheets on backyard conservation

Backyard

Conservation

Finding a pest problem and then treating for that problem – such as spot

spraying – is cost effective and limits

any damage to non-targeted species.
BACKYARD Pest Management

2

Insects damage plants in several

ways.The most visible damage is

chewed plant leaves and flowers.

Many pests are visible and can be

readily identified, including the

Japanese beetle, Colorado potato

beetle, and numerous species of

caterpillars such as tent caterpillars

and tomato hornworms. Other chewing insects, however, such as cutworms (which are caterpillars) come

out at night to eat, and burrow into

the soil during the day.These are

much harder to identify but should

be considered if young plants seem

to disappear overnight or are found

cut off at ground level.

Sucking insects are extremely common and can be very damaging.

These insects insert their mouth

parts into the plant tissues and suck

out the plant juices.They also may

carry diseases that they spread from

plant to plant as they move about

the yard.You may suspect that these

insects are present if you notice misshapen plant leaves or flower petals.

Often the younger leaves will appear

curled or puckered. Flowers developing from the buds may only partially

develop. Look on the underside of

the leaves as that is where many

species tend to gather. Common

sucking insects include leafhoppers,

aphids, mealy bugs, thrips and mites.

Other insects cause damage by boring into stems, fruits, and leaves.

They may disrupt the plant’s ability

to transport water.They also create

opportunities for disease organisms

to attack the plants.You may suspect

the presence of boring insects if you

see small accumulations of sawdustlike material on plant stems or fruits.

Common examples of boring insects

include squash vine borers and corn

borers.

Diseases

Plant disease identification is

extremely difficult. In some cases,

only laboratory analysis can conclusively identify diseases. Disease

organisms injure plants in several

ways. Some attack leaf surfaces and

limit the plant’s ability to carry on

photosynthesis. Other organisms produce substances that clog plant tissues that transport water and nutrients. Other disease organisms produce toxins that kill the plant or

replace plant tissue with their own.

Symptoms associated with plant diseases may include the presence of

mushroom-like growths on trunks of

trees; leaves with a grayish mildewy

appearance; spots on leaves, flowers,

and fruits; sudden wilting or death of

a plant or branch; sap exuding from

branches or trunks of trees; and

stunted growth.

Misapplication of pesticides and

nutrients, air pollutants, and other

environmental conditions such as

flooding and freezing can also mimic

some disease problems.Yellowing or

reddening of leaves and stunted

growth may indicate a nutritional

problem.At first glance, blossom end

rot of tomato, in which the bottom

of the tomato turns black, might

appear to be a disease caused by

some pathogen. It is actually caused

by the plant’s inability to take up calcium quickly enough during periods

of rapid growth. Prevent this problem with adequate moisture–adding

more calcium is of no benefit! Leaf

curling or misshapen growth may be

a result of herbicide application.

Pest management

practices

Preventing pests should be your first

goal. But it’s unlikely you will be able

to avoid all pest problems, since

some plant seeds and disease organisms lay dormant in the soil for

years.

Diseases need three elements to

become established: the disease

organism, a susceptible species, and

the proper environmental conditions. Some disease organisms can

live in the soil for years; other organisms are carried in infected plant

material that falls to the ground.

Some disease organisms are carried

by insects. Good sanitation will help

limit some problems. Planting resistant varieties of plants prevents

many diseases. Rotating annual crops

in a garden also prevents some diseases.

You will likely have the most opportunity to alter the environment in

favor of the plant and not the disease. Healthy, vigorous lawn and garden plants have a higher resistance

to pests. Plants that have adequate,

but not excessive, nutrients are better able to resist attacks from both

diseases and insects. Excessive rates

of nitrogen often result in extremely

succulent vegetative growth and can

make plants more susceptible to

insect and disease problems, as well

as decrease their winter hardiness.

Proper watering and spacing of

plants limits the spread of some diseases. Some disease species require

free standing water in which to

spread, while other species just need

high humidity. Proper spacing provides good aeration around plants.

Trickle irrigation where water is

applied to the soil and not the plant

leaves may be helpful.

Barriers may be effective to exclude

some pests. Mulching is effective

against weeds. Fences can limit damage from rabbits. Row covers may

prevent insect damage on young vegetable plants. Netting can be applied

to small fruit trees and berries to

limit damage from birds.
Integrated Pest

Management (IPM)

It is difficult, if not impossible, to

prevent all pest problems every year.

If your best prevention efforts have

not been entirely successful, you

may need to use some control methods. Integrated Pest Management

(IPM) relies on several techniques to

keep pests at acceptable population

levels without excessive use of

chemical controls.The basic principles of IPM include monitoring

(scouting), determining tolerable

injury levels (thresholds), and applying appropriate strategies and tactics. Unlike other methods of pest

control where pesticides are applied

on a rigid schedule, IPM applies only

those controls that are needed, when

they are needed, to control pests

that will cause more than a tolerable

level of damage to the plant.

Monitoring is essential for a successful IPM program. Check your plants

regularly. Look for signs of damage

from insects and diseases as well as

indications of adequate fertility and

moisture. Early identification of

potential problems is essential.

There are thousands of insects in the

garden, many of which are harmless

or even beneficial. Proper identification is needed before control strategies can be adopted. It is important

to recognize the different stages of

insect development for several reasons.The caterpillar eating your

plants may be the larvae of the butterfly you were trying to attract.The

small larvae with six spots on its

back is probably the young of the

ladybug, a very beneficial insect.

Some control practices are most

effective on young insects. Different

stages may also be more damaging

than others.

It is not necessary to kill every

insect, weed, or disease organism to

have a healthy yard.This is where

the concept of thresholds comes in.

The economic threshold is the point

where the damage caused by the

pest exceeds the cost of control. In a

home garden, this can be difficult to

determine.What you are growing

and how you intend to use it will

determine how much damage you

are willing to tolerate. Remember

that larger plants, especially those

close to harvest, can tolerate more

damage than a tiny seedling.A few

flea beetles on a radish seedling may

warrant control whereas numerous

Japanese beetles eating the leaves of

beans close to harvest may not.

If the threshold level for control has

been exceeded, you may need to

employ control strategies. Strategies

can be discussed with the

Cooperative Extension Service, garden centers, or nurseries.

Control strategies

Mechanical/physical controls 

Insects--

Many insects can be removed by

hand.This method is preferable if a

few, large insects are causing the

problem. Simply remove the insect

from the plant and drop it into a

container of soapy water or vegetable oil. Caution: some insects have

spines or excrete oily substances

that can cause injury to humans. Use

caution when handling unfamiliar

insects.Wear gloves or remove

insects with tweezers.

Many insects can be removed from

plants by spraying water from a hose

or sprayer. Small vacuums can be

used to suck up insects.Traps can be

used effectively for some insects.

These come in a variety of styles

depending on the insect to be

caught. Many traps rely on the use of

pheromones--naturally occurring

chemicals produced by the insects

and used to attract the opposite sex

during mating.They are extremely

specific for each species and, therefore, will not harm beneficial

species. One caution with traps is

that they may actually draw more

insects into your yard.You should

not place them directly in the garden. Other traps are more generic

and will attract numerous species.

These include such things as yellow

and blue sticky cards. Different

insects are attracted to different colors. Sticky cards can also be used

effectively to monitor insect pests.

Weeds--

Hoeing, pulling, and mulching are

the most effective physical control

methods for weeds.Weeding is most

important while plants are small.

Well established plants can often tolerate competition from weeds.

Diseases--

Removal of diseased material limits

the spread of some diseases. Clean

up litter dropped from diseased

plants. Prune diseased branches on

trees and shrubs.When pruning diseased trees and shrubs, disinfect

your pruners between cuts with a

solution of chlorine bleach to avoid

spreading the disease from plant to

plant. Control insects known to

spread plant diseases.

Other pests--

Fences, netting, and tree trunk

guards can be extremely successful

in limiting damage from small mammals and birds. Numerous traps are

also available to catch or kill some

animals. Caution: In many states it is

illegal to move wildlife, including

squirrels.Traps may also catch animals other than the ones targeted.

Check local regulations before trapping.

Diatomaceous earth, a powder-like

dust made of tiny marine organisms

called diatoms, can be used to

reduce damage from soft-bodied

insects and slugs. Spread this material on the soil--it is sharp and cuts or

BACKYARD Pest Management

3
BACKYARD Pest Management

4

irritates these soft organisms. It is

harmless to other organisms. Shallow

dishes of beer can be used to trap

slugs.

Biological controls

Biological controls are nature's way

of regulating populations. Biological

controls rely on predators and parasites to keep organisms under control. Many of our present pest problems result from the loss of predator

species.

Other biological controls include

birds and bats that eat insects.A single bat can eat up to 600 mosquitoes

an hour. Many bird species eat insect

pests on trees and in the garden.

Bacillus thuringiensis (Bt) is a bacteria that specifically attacks larvae of

some insect pests including white

grubs in the lawn and Japanese beetles.This bacteria is harmless to

desirable species.

Chemical controls

When using biological controls, be

very careful with pesticides. Most

common pesticides are broad spectrum in that they kill a wide variety

of organisms. Spray applications of

insecticides are likely to kill numerous beneficial insects as well as the

pests. Herbicides applied to weed

species may drift in the wind or

vaporize in the heat of the day and

injure non-targeted plants. Runoff of

pesticides can pollute water. Many

pesticides are toxic to humans as

well as pets and small animals that

may enter your yard.

Some common, non-toxic household

substances are as effective as many

more toxic compounds.A few drops

of dishwashing detergent mixed

with water and sprayed on plants is

extremely effective in controlling

many soft-bodied insects such as

aphids and whiteflies. Crushed garlic

mixed with water may control certain insects.A baking soda solution

has been shown to help control

some fungal diseases on roses.

When using pesticides, follow label

directions carefully.Altering the rate

of application or increasing the frequency of application can injure

desirable plant and animal species.

Spot applications of the pesticide to

the targeted pest can reduce the

amount used and help reduce the

risk of injury to non-targeted

species. Do not apply on windy days.

Read the label for information on

other environmental conditions such

as temperature and rain that may

influence the pesticide’s effectiveness. Be aware that many so-called

"organic" pesticides may be just as

toxic as the synthetic or chemical

products.

On the farm 

Proper pest management on the

farm involves a variety of practices,

such as rotating crops to reduce disease and insect problems, and establishing tall grass hedges to provide

habitat for beneficial insects. Many

farmers now monitor their fields regularly--a practice called scouting--to

keep track of insect and weed populations. Only when populations reach

a level where an unacceptable

amount of damage is likely are direct

control measures initiated.When

pesticides are necessary, farmers fill

and clean tanks away from water

sources, mix only necessary

amounts, and apply only to land

where problems exist.

Many farmers are using IPM techniques for effective and economic

control of pests. Based on monitoring of specific pests, farmers apply

only those pesticides needed for adequate control.

Lacewing

Ladybug

Praying 

mantis

Ground

beetle

Trichogramma

wasp

Some 

beneficial

insects

Controls

aphids, mealy bugs, thrips, spider mites

aphids, Colorado potato beetle

almost any insect

caterpillars that attack trees and shrubs

grubs, beetles, cutworms, army worms

corn borer, cabbage looper, other worms

weeds

Beneficial Insect

Green lacewings

Ladybugs

Praying mantis

Ground beetles

Parasitic nematodes

Trichogramma wasp

Seedhead weevils

Printed by the National Association of Conservation Districts 1-800-825-5547