The cotton bollworm is native to North and South America and is commonly found throughout the United States. The cotton bollworm feeds on a wide range of crops including corn, cotton, alfalfa, bean, grain sorghum, lettuce, peanuts, pecan, pepper, tobacco and tomatoes. Cotton bollworm also feeds on a wide range of non-cultivated crops depending on geography. Because of its wide host range, it is known by several common names including corn earworm and tomato fruitworm.

The cotton bollworm is an important pest of cotton and the larvae can be easily confused with tobacco budworm. Cotton bollworm tend to be more prevalent in the eastern cotton growing states on an annual basis, but can be found throughout the cotton growing areas in large numbers during some years. Cotton bollworm has become more important in areas where tobacco budworm was the main concern due to the introduction of Bacillus thuringiensis (Bt) cotton. Early Bt cotton varieties have not offered good control of cotton bollworm. More recent versions of Bt cotton, including WideStrike™ Insect Protection, offer improved bollworm control.

Biology
Cotton bollworm overwinters as pupae in the soil with adults emerging in March when temperatures warm up. Two generations may occur before cotton bollworm move into cotton. Early hosts range from common weed species to geranium, sweet corn and tomato. Once in cotton, large populations can develop. Females will lay up to 1,500 eggs over a 3 to 12 day period in cotton. The eggs are initially white in color and are frequently found on the upper third of the plant. Usually eggs are laid on smaller leaves or in terminals. If hot dry conditions exist however, moths may lay further down in the plant canopy. Eggs darken as they mature and hatch in 3 to 5 days depending on the temperature. Larvae normally double in size every day for the first four days. Larvae will feed for 16 to 17 days before pupating in the soil. A complete life cycle may take 27 to 35 days during the hot summer months, but will be longer during cooler months.

Multiple generations can occur. The number of generations depends on climate. In the southern United States, 6 to 10 generations may occur. In these areas, generations frequently overlap.