The cotton bollworm, also known as the corn earworm or tomato fruitworm, and the tobacco budworm, a different species, combine to form the greatest insect complex attacking crops in S.C.
The larvae of the cotton bollworm and the tobacco budworm cannot be distinguished in the field when found on cotton. Microscopic examinations of mouth parts and tubercles must be made for positive identification.
The brown moth of the cotton bollworm has a wingspan of 1 1/2 inches. The tobacco budworm moth is about the same size but is greenish-brown with three lighter diagonal stripes on the fore wings. Both species lay single white eggs on the top of leaves and fruiting bracts. Eggs turn brown in 3 days as hatching begins.
The brown-headed larvae may feed on terminal growth before moving to squares, blooms, or bolls. Damaged squares will flare and bolls may rot. After feeding for 2 to 3 weeks, the larvae enter the soil and pupate. Twelve days later the moths emerge, feed, mate, and lay eggs. Life cycle varies from 33 to 46 days. Bollworms overwinter as pupae in the soil.
The more important host plants of cotton bollworms are corn, cotton, tobacco, tomatoes, vetch, grain sorghum, and soybeans. The tobacco budworm has a more restricted host range, the most important being tobacco, cotton, crimson clover, and tomatoes.
