Source: Gyorgy Csoka, Hungary Forest Research Institute, Bugwood.org
Common Name: American Bollworm, Cotton Bollworm, Corn Earworm, Tomato Fruitworm
Latin Name: Helicoverpa armigera, Helicoverpa zea, Helicoverpa punctigera
Main Host(s): Field and row crops, e.g. cotton, corn, and fruiting vegetables such as tomato, lettuce, beans, pigeon pea, cowpea, sorghum, etc.
Helicoverpa zea is known by numerous different common names including Cotton Bollworm or Corn Earworm, and many others specific to the crop on which it can be found. This damaging pest is native to North America. In Europe, Asia, Africa, and Australia the species is Helicoverpa armigera. While Helicoverpa armigera is a problem in many parts of the (old) world, it is a particularly difficult pest in Australia and India, where it is the number-one pest of cotton, and in Southeast Asia, where it is the most significant pest on vegetables. Regardless, Helicoverpa species worldwide have numerous host plants.
Adult moths of Helicoverpa species are vigorous flyers moving into the colder regions in the summer. The number of generations can vary from 1-2 in the colder regions and up to 7 in warmer climates. They hone in on the best host plant (be it an agricultural crop or weedy plant, depending on the part of the season) for egg laying and larval feeding. Eggs are laid singly and hatch in 3-4 days.
Larvae of Helicoverpa species can have from 5-6 instars or up to 7-8 depending on environmental/host conditions. They have a tendency to feed and bore preferentially into a crop’s flowering or fruiting structures or into clusters of leaves (as in lettuce).
The larvae feeding behavior of boring into plant structures makes Helicoverpa pests very destructive. For example, one larvae in a corn ear render it unmarketable. Infestations of flower buds of cotton (squares) will also have a great impact on yield. This feeding behavior is also challenging for many insecticides to provide optimal control.
Pheromone traps are available for monitoring adult Helicoverpa pest populations in high value vegetable crops. Helicoverpa species have developed resistance to several insecticides, such as pyrethroids and insect growth regulators. For this reason, a program using DiPel® (and/or XenTari®) is an important means to control these destructive pests.