Life History and Damage

Figure 42. Frass at the stem base of a bell pepper indicates tunneling by a European corn borer larva.

Figure 43. Larva of European corn borer in bell pepper that has premature reddening of fruit (C. E. Mason).

The life history of the European corn borer on peppers usually involves the midsummer and late generations. Occasionally, early- summer larvae are found on transplants that were infested in seed beds. Normally, European corn borer does not prefer peppers as a host. Infestations in peppers usually occur when corn becomes relatively unattractive to egg-laying moths due to plants reaching maturity. Consequently, females lay eggs on pepper plants as an alternative. They are capable of infesting any of the many cultivars of peppers, including those that are hot. Egg masses usually are deposited on leaves. The eggs hatch in 3 to 7 days, and the larvae disperse over the plant. First instars enter the upper part of the fruit by crawling under the calyx (cap) and boring into it (Figure 42) or into the fruit wall. First and second instars feed on the calyx, flesh around the calyx, or in the placenta. Third instars may continue feeding on the pepper fruit, or may leave the fruit. Those leaving the fruit commonly bore into uninfested fruit or into stems. Larvae continue to develop and may pupate in fruit or stems. Or, if late enough in the season, larvae may go into diapause and overwinter in stems and fruit peduncles.

Fruits infested early usually rot and drop off the plant. Fruit infested late in development may appear healthy or show premature reddening (Figure 43) but are rejected upon marketing or processing because of contamination by European corn borer. Damage from feeding around the calyx also may reduce the size and quality of fruit that escape internal infestation.