Coleoptera Chrysomelidae

Natural History

Distribution. Eggplant flea beetle is widely distributed in the United States. It is found from the east coast to the west coast except in northern areas. It is found only as far north as New Jersey, Illinois,

Nebraska, and Utah. This native species is not known as a pest in Canada.

Host Plants. Eggplant flea beetle feeds on solanac-eous plants such as eggplant and potato. The host range of eggplant flea beetle is poorly known, but likely is equivalent to that of potato flea beetle, Epitrix cucumeris (Harris). Jewett (1929) reported eggplant flea beetle to be more abundant on potato in Kentucky than potato flea beetle.

Natural Enemies. The natural enemies of eggplant flea beetle are poorly studied, but should be equivalent or identical to those of potato flea beetle.

Life Cycle and Description. There are two generations annually in Kentucky, with overwintering occurring in the adult stage. Overwintering occurs in the soil. A complete generation, egg to adult, is estimated to require 30-45 days.

Adults emerge in the spring, usually April in Indiana and early May in Kentucky, and soon begin egg production.

  1. The eggs are deposited in the soil beneath host plants, usually at a depth of 1-2 cm. They are laid singly, but sometimes small clusters are produced. The egg is elliptical in shape and whitish. The egg measures 0.40-0.45 mm in long and 0.21-0.23 mm wide. Eggs hatch in 6-8 days.
  2. Upon hatching, the larva measures about

1 mm long, but eventually attains a length of 3.54.5 mm. The larva is whitish with a brown head and brownish anal plate. The larva bears anal prolegs. The larvae feed on roots and rootlets, but also burrow into the tissues, creating surface scars and tunnels. Their development time varies considerably, depending on the weather, but generally averages about 20 days (range 17-25 days). There are three instars, with development times of about 4, 9.5, and 7.1 days, respectively.

  1. During the last 1-4 days of the larval stage, the larva shortens, thickens, and forms a pupal cell in the soil. Pupation occurs at depths ranging from less than 1.0 cm to 7.5 cm. Initially, the pupa, which resembles the adult in form, is white. It darkens considerably, however, before emergence. Duration of pupation averages about 6 days (range 4-8 days). The adult may remain in the pupal cell for 2-3 days before escaping.
  2. The adult is rather oval and measures about

2 mm long. The body is black and densely covered with short hairs. The antennae and legs are reddish-yellow, except for the black femora. The hind femora

Adult eggplant flea beetle.

are enlarged. The pronotum is densely marked with large, deep punctures, and the elytra with rows of fine punctures. This beetle is quite similar to potato flea beetle, but eggplant flea beetle can be distinguished using the following characters: the elytra of eggplant flea beetle are more densely hairy, the transverse depression at the posterior of the pronotum is not pronounced, and the femora of the front and middle legs are completely black. Overwintering and summer adults can live for more than two months. Feeding commences soon after emergence from the soil, and egg production begins two weeks later. In Kentucky, overwintering beetles produced eggs from mid-May to mid-June, whereas first brood adults produced eggs from mid-July to mid-August. Second brood beetles do not produce eggs. As the weather becomes cold, beetles aggregate under organic litter and eventually dig into the soil and enter diapause until spring.

The biology of eggplant flea beetle was given by Jewett (1929).

Damage

The adults chew small holes in the leaves. They feed on either the upper- or lower-leaf surface, but the latter is preferred. Adjacent tissue, while not eaten, often dies. The leaves acquire a rusty or burned appearance when heavily damaged. When attacked early in the growth of the plant, stunting results.

The larvae feed belowground on rootlets, roots, and tubers. Severe root pruning may occur. Damage to potato tubers, which is typically in the form of pitting or roughening, resembles damage by potato flea beetle and tuber flea beetle.

Management

Management of eggplant flea beetle, which has not been well studied, should be equivalent to potato flea beetle.

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