Genetic Improvement ofHelicoverpa zeaNuclear Polyhedrosis Virus as a Biopesticide

Helicoverpa zeanuclear polyhedrosis virus, which was previously registered and commercially produced as a pesticide (Elcar), was genetically improved to control the cotton bollworm,H. zea.A significant reduction in the time required for this virus to killH. zealarvae was achieved by inserting a mite gene encoding a potent insect-selective neurotoxin gene,tox34,into the viral gene encoding ecdysteroid UDP-glucosyltransferase. Under the control of an early viral promoter, expression oftox34during infection resulted in 50% mortality or paralysis within 40 h after virus treatment. The ability to genetically improve the properties of this virus as a pesticide provides the opportunity to develop a commercially viable product to control this pest species.