Insect Note #27 (Revised)

Prepared by:
Kenneth A. Sorensen, Extension Entomologist

Dated 2/94
Placed on the Web 4/95 by the Department of Entomology, NCSU

Flea Beetles on Vegetables

Coleoptera: Chrysomelidae At least six species of flea beetles attack vegetables in North Carolina. Potato, tobacco and corn flea beetles are most common and have wide host ranges. The striped flea beetle is limited to plants of the cabbage family, the eggplant flea beetle to eggplant, and the sweetpotato flea beetle to sweetpotatoes, corn, and plants of the morning glory family. Adults attack the foliage and chew small, round holes giving a 'shot-hole' appearance. Larvae feed on the roots of host plants.

Biology

Adults generally overwinter and trash around fields of host plants, and move to weeds and plant beds in early spring and later to transplanted vegetables and garden plants. They are most destructive to young plants. They lay eggs scattered on the soil beneath host plants. Eggs hatch in about 10 days, and the slender, white larvae feed on and tunnel in underground stems, roots and/or tubers for 3 to 4 weeks. There are usually 3 instars. Pupae usually remain in the soil for 7 to 10 days until adults emerge and the cycle is completed. There are 3 or more generations per year.

Description

Adult - The potato and eggplant flea beetles are about 1/10 inch long and nearly uniform black. The equally small tobacco flea beetle is yellowish-brown with a dark band across the wings. The sweetpotato and corn flea beetles, about the same size, have a bronzy reflection. The striped flea beetle is about 1/2 inch long with a crooked, yellowish strip on each wing cover. All have thickened hind legs which enable them to jump, and hence, their common name.

Larva - Larvae are mostly whitish, slender, delicate, cylindrical worms from 1/8 to 1/3 inch long when fully grown with minute legs and brownish heads.

Host Plants

Some flea beetles are general feeders, but most attack only closely related plants. The potato and tobacco flea beetles attack potato, tobacco, tomato, pepper, horsenettle and related weeds. The eggplant flea beetle, striped flea beetle (cabbage family only), and the sweetpotato flea beetle are fairly specific. The corn flea beetle is a general feeder.

Damage

Adult flea beetles chew very small, rounded holes in leaves, causing a short-hole appearance. These holes provide an entrance for plant diseases. The potato flea beetle spreads early blight. The corn flea beetle vectors bacterial wilt of corn. Larvae feed on roots, and with the sweetpotato and potato flea beetles, heavy losses to edible roots or tubers may result.

Distribution

Flea beetles are worldwide in distribution. All species are common in the eastern United States.

Control

Keeping fields free of weeds is important. Late planting also favors growth of host plants over establishment of flea beetles. Destroy plant residues and piles of cull potatoes to prevent beetle buildup. Trash around plant beds where beetles hibernate should be destroyed and beds covered.

A number of insecticides (granular and foliar) are available to control adult flea beetles. Planting resistance sweetpotato varieties is the only effective control measure for the sweetpotato flea beetle.

The use of brand names and any mention or listing of commercial products or services in this publication does not imply endorsements by the North Carolina Cooperative Extension Service nor discrimination against similar products or services not mentioned. All pesticide recommendations provided in this publication apply to pest control in North Carolina. Individuals who use chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain information about product usage in your locale and examine a current product label before applying any chemical. The information presented on pest biology is based on conditions in North Carolina and may not be applicable to your locale. For further information, we recommend that you contact the Cooperative Extension Service office in your county.