The Japanese beetle : how we fight it

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BRANCH

. . . HOW WE FIGHT IT

UNITED STATES DEPARTMENT OF AGRICULTURE'PA-375

. . . HOW WE FIGHT IT

The Japanese Beetle is a highly destructive plant pest.
The grub feeds on the roots of grasses and destroys turf.
The adult feeds on flowers, shrubs, trees, and fruit; and
on field crops, such as corn and soybeans.

A native of Japan, the beetle was discovered in the
United States in 1916 near Riverton, N.J. It has since
spread over much of the Eastern United States and is now
found from southern Maine southward into Alabama and
Georgia and westward into Michigan, Illinois, Missouri,
and Tennessee.

Grubs of the Japanese beetle feed on the roots and
underground stems of grasses and other plants. Often this
feeding goes unnoticed until the plants fail to grow prop-
erly, or until they die. When the grubs are numerous, they
can cause serious damage to turf.

Adult Japanese beetles feed on nearly 300 different
kinds of plants. The beetles often congregate and feed on
flowers, foliage, and fruit that are exposed to bright
sunlight.

J-722, BN-33300

Left, eggs of the Japanese beetle. About 7 times natural
size. Right, grub in three stages of growth: (A) Midsum-
mer; (B) early autumn; (C) late autumn and spring.
About natural size.

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When feeding on leaves the beetles usually chew out the
tissue between the veins and skeletonize the leaves. Some-
times they make many large, irregular holes in the leaves.

If a tree or shrub is heavily infested with Japanese
beetles it can lose most of its leaves in a short time.

The beetles often mass on ripening fruit and feed until
nothing edible is left. They seldom feed on unripe fruit.
They seriously damage corn by eating the silk as fast as it
develops. This prevents the kernels from forming.

The adult Japanese beetle is a little less than V2-mcn
long and has a shiny green body and bronze-colored outer
wings. It has six small tufts of white hairs along each side
of its body, under the edges of the wings. The male and
female beetles look similar, but the males usually are
slightly smaller than the females.

BN-33298, BN-5089

Pupa (left), about 3^ times natural size. Adult Japanese
beetle (right), about 2^4 times natural size.

_ PN-1911

Turf damaged by grubs.

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PN1912, BN-33302

Top, beetles feeding on soybean leaves. Bottom, beetles
feeding on peaches.

The Japanese beetle spends about 10 months of the year
in the ground as a white grub. The grub is similar to our
native white grub, but it is usually smaller, about 1 inch
long when fully grown. It lies in the soil in a curled
position.

The adult beetles first appear on their favorite food
plants in late spring or early summer, depending on the
area. They are very active for 4 to 6 weeks. Then they
gradually disappear.

The beetles fly only in the daytime. They are particu-
larly active on warm, sunny days and move quickly about
the plants.

From time to time, the female beetles leave the plants
on which they have been feeding, burrow about 3 inches
into the ground — usually where there is turf — and lay a
few eggs from which the grubs will later hatch. After the
eggs are laid, the females return to the plants and continue
to feed.

By midsummer the eggs hatch and the young grubs
begin to feed. In late autumn the grubs burrow 4 to 8
inches into the soil. They remain inactive all winter. In

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BN-7846X, BN-33299

Beetle damage to corn. Left, beetles feeding on cornsilks.
Right, resulting malformation of ears.

early spring they return to the turf, where they continue
to feed on roots until late spring. Then they change into
pupae. In about 2 weeks the pupae become adult beetles
and emerge from the ground.
The life cycle takes 1 year.

Your Federal and State governments are working to-
gether to control the Japanese beetle with surveys to find
it, quarantines to keep it from moving to new areas, treat-
ments with biological organisms and chemical pesticides
to suppress it, and research to find safer, more effective
ways to combat it.

SURVEYS

Plant protection workers use survey traps to find new
infestations. Aromatic baits are placed in the traps to
attract the beetles. The traps, usually green or yellow, are
the major detection device in the Federal-State program.

The workers also examine favored host plants to find
the beetles. Once the skeletonized leaves are discovered,
the adult beetles are usually found very quickly.

QUARANTINES

Beetle-infested areas are under Federal and State
quarantines. The Federal quarantine is designed to pre-
vent interstate spread of the pest; State quarantines serve
to halt its spread within State Borders. These quarantines
require articles that might harbor Japanese beetles to be
certified free of the pest before they may be moved from
the area.

Some of the articles that must be certified are: soil,
grass sod, plants, and soil-moving equipment that has been

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Applying milky disease powder.

used in the quarantined area. If adult beetles are numerous
in an area, certain farm produce may require certification
before it is moved to a non-infested area.

Homeowners in the infested areas who wish to swap
plants with out-of-town friends should first consult their
county agricultural agent or a Federal or State plant pro-
tection inspector to determine if quarantine regulations
affect the exchange of plants.

Homeowners and gardeners from noninfested areas
should remember that a certificate is required for some
plants that come from an area under quarantine.

Plant protection workers sometimes apply biological
organisms or chemical pesticides to soil and foliage to sup-
press new infestations before they become unmanageable.

If possible, biological controls are used. One of these is
milky disease, a bacterial disease that infects and kills the
grub without causing harm to other animal life.

Chemical pesticides are used only where they will not
adversely affect the environment or nontarget organisms.

RESEARCH

Entomologists, chemists, engineers, and other USDA
scientists are searching for new and safer ways to control
the Japanese beetle. Saturation trapping to replace pesti-
cides in control programs is being investigated. New baits
and trap distribution patterns are being developed to in-
crease the effectiveness of the survey.

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WHAT YOU CAN DO

Your help is needed to prevent the spread of the Jap-
anese beetle. You can help if you do these things :

• Organize a community-wide campaign to treat soil
with milky disease. Milky disease is a natural enemy of the
Japanese beetle grub. Dust mixtures that contain spores
of the organism causing this disease are available com-
mercially but the supply is limited. They are most effective
when applied throughout a community, but they may be
applied to individual properties. Usually, the disease works
slowly, and its effects may not be evident for several years.
It kills grubs in the soil, but it does not prevent beetles
from flying in from untreated areas. It is harmless to
plants and to humans and all other forms of animal life.

• Make your property unattractive to beetles. Remove
all ripening and rotten fruit as soon as possible. Clean out
weeds and other unwanted plants. Keep desirable plants
healthy. If possible, select plants that do not attract the
beetles. Do not set out susceptible plants until after the
height of the beetle season.

• Protect turf and other plants with chemical pesticides
or biological organisms such as milky disease. To obtain
these products, contact your local garden supply store.
Follow label directions explicitly.

• Report new infestations to your county agricultural
agent.

• Do not use beetle traps to protect plants. They may
attract more beetles to your property while catching only
a small percentage of them, thus increasing the likelihood
of damage. Traps are primarily for use by Federal and
State officials to obtain information about the distribution
and spread of the beetle.

• Check with your county agricultural agent or your
State or Federal plant protection inspector if you are
moving to another area, or if you intend to swap plants
with out-of-town friends. These officials can tell you what
quarantine restrictions you will need to observe. Insect
collectors should not exchange live insects. Do not mail
live insects.

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Prepared by
Plant Protection and Quarantine Programs
Animal and Pl\nt Health Inspection Service

Washington, D.C. Revised April 1972

U. S. GOVERNMENT PRINTING OFFICE : 1972 O - 452-2 44