Cotton Insect Pests
Although bollworm and tobacco budworm are two distinct species, the larvae can be difficult to distinguish. Both are robust, variously colored caterpillars that feed on cotton fruit. One of the best ways to distinguish between these two species of caterpillars is to check for the presence of an extra tooth on the inner surface of the mandible, a character that is present in tobacco budworm but absent in bollworm. However, this method is difficult to use with small caterpillars. The moths, on the other hand, are easy to distinguish. The tobacco budworm moth has three distinct diagnoal strips on each wing, while the bollworm moth is larger, buff tan in color, and usually has a distinct dark spot in the center of each front wing. Both species deposit their eggs individually. Eggs are most commonly deposited on the upper surface of developing leaves, but eggs are lain on many other locations on the plant as well. Small larvae of both species are most commonly found feeding in terminals or squares, while larger larvae are most often found feeding in bolls. Both species form their pupae in the soil, which is also the stage and site in which overwintering occurs.