University of Vermont Extension
Department of Plant and Soil Science

Flea Beetles                                          EL 71

by G.R. Nielsen, Former Extension Entomologist, Plant and Soil Science Department

Many species of flea beetles* attack the leaves and other parts of vegetables, fruits, and flowers, as well as weeds.
Adult flea beetles seem to prefer young transplants. A leaf injured by this insect looks as though it has been shot full of
holes. Flea beetles are usually dark or black in color and about 1/16 inch long. When disturbed, they jump about like
fleas, hence the name "flea beetle."

Injury: Adult flea beetles feed on the leaves of cabbage, radish, corn, horseradish, tomato, kale, cucumber, melon,
grape, spinach, potato, eggplant, and related vegetable crops. They also feed on strawberries and chrysanthemums.
Some species such as the elm flea beetle even attack trees. Slow-growing transplants and seedlings may be heavily
damaged by the flea beetle and even die.

Flea beetle larvae feed on the roots and tubers of the whole plant. The tuber flea beetle scars the surface of potato
tubers or bores into them causing discoloration. Most species attack only closely related plants. Others, such as the
red-necked flea beetle, breed on weeds such as smartweed, and then move to unrelated plants such as corn,
strawberries, and other plants.

Some flea beetles are known to be vectors of disease organisms. For example, the potato flea beetle spreads the
causal organism of spindle tuber blight, brown rot, and potato scab, and the corn flea beetle is involved in the spread
of Stewart's bacterial wilt of corn.

Life History: The life cycles of the several species of flea beetle vary somewhat, but follow a general pattern. Usually
the adult beetles pass the winter hibernating under leaves, grass, or debris around the margins of fields, or woods, in
ditches or on streambanks. As they emerge from hibernation in the early spring, many of the species feed on weeds
and foliage of trees until vegetable plants are available in the garden. They can be frequent and serious pests in
seedbeds and on newly transplanted vegetables. In late spring the female beetle lays her eggs at the base of garden
plants, which hatch in 5 to 8 days. The larvae feed on the roots for 2 to 3 weeks and then enter the pupal stage for 2
weeks. The larvae of most flea beetles are whitish, slender, worms 1/8- to 1/3-inch long when full grown, with tiny legs
and brownish heads. Adults emerge from the pupal stage in midsummer and the cycle is repeated.

There are one or two generations per year. Some flea beetles common in Vermont whose life cycle varies from this
pattern are the spinach flea beetle, which lays its eggs on spinach leaves and whose larvae feed on the under surface of
the leaf, and the horseradish and sinuate-striped flea beetles, which also lay their eggs on the foliage.

Controls: Depending upon the flea beetle species involved and the crop, there may be some cultural home remedies
or chemical treatments that you can apply to control these pests.

A. Cultural Control

1.Control weeds in and around the garden or vegetable area.
2.Eliminate, as much as possible, trash in which the beetles can overwinter.
3.Because flea beetles are sun-loving, plant tolerant crops in the shade.
4.Screen seedbeds with gauze or screening mesh (25 mesh per inch) to shield the pests from the delicate, young,
developing plants.
5.Make a sticky shield or box coated with tree tanglefoot and pass it over the infested plants to trap flea beetles
leaping from disturbed foliage.
6.Plant seeds thickly, and thin after the early flea beetle season has passed.
7.Interplant potatoes and other susceptible vegetables with or near shade-producing crops.

B. Home Remedies: Flea beetle home remedies reported include the following:

1.A repellent foliage spray made with whole crushed garlic cloves.
2.Wood ashes sprinkled around plants, especially on potatoes.

C. Chemical Control: Insecticide treatments for flea beetle control vary with the species and the crop. Anticipate flea
beetle infestation of transplants and new seedings and be ready to begin treatments as soon as the flea beetles appear.
Most flea beetle treatments are applied as foliar sprays to protect the foliage against the feeding of the adult beetle. To
prevent adults from laying eggs for a larger second generation of infestation the next year, be sure that treatment starts
early and controls the flea beetles. Because the larvae of flea beetles feed on the tubers in the soil, apply insecticide in
the soil around potatoes.

Insecticides for the control of flea beetle are available in dust (D), wettable powder (WP), flowable liquid (F), and
emulsifiable concentrate (EC). Products must be used in accordance with the label directions. These products may
have varying restrictions on intervals between treatment and harvest.

*Species of flea beetles include Altica, Chaetocnemy, Disonycha, Epitrix, Phyllotreta, Systena spp. and others
(Coleoptera: Chrysomelidae).

Before using any pesticide, read the label and follow all precautions!

Edited in January 1997, based on material developed in 1984.

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