Effects of Sublethal Doses of Two Insect Growth Regulators on Helicoverpa zea (Lepidoptera: Noctuidae) Reproduction2

Abstract

The effects of sublethal doses of two insect growth regulators on Helicoverpa zea (Boddie) reproduction were investigated. Adults which developed from larvae that fed on a pinto bean diet containing diflubenzuron (Dimilin) or an ecdysone agonist (RH 5992) were inbred and outcrossed with adults which developed from larvae that were fed on a normal pinto bean diet. Data were collected on fecundity, fertility, and sperm transfer. Sublethal doses of both compounds administered to H. zea larvae caused reduced fertility in surviving male imagos but had no effect on fecundity or fertility of the female imagos. Reduced fertility in treated males was largely caused by a lower incidence of sperm transfer. Implications of our results for H. zea population management are discussed.