A test program was initiated during the 1992 cotton season for evaluation of DiPel ES applied alone and in combination with chemical insecticides for control of bollworms (Helicoverpa zea) and the tobacco budworm (Heliothis virescens). Full-season use of DiPel ES is an expansion of the original concept of using a Bt (Bacillus thuringiensis) product mainly during the early-season period.

Major reasons for this change are (1) for preservation of beneficial arthropods thereby reducing the potential for flaring secondary pests such as aphids and mites and (2) the need for lowering selection pressure on the synthetic pyrethroids. Results of the 1992 field trials with DiPel ES demonstated that effective worm control can be achieved in comparison against standard chemical insecticide programs.