Comparative status of insecticide resistance in theHelicoverpaandHeliothisspecies (Lepidoptera: Noctuidae) of south India

Abstract

AbstractHelicoverpa armigera(Hübner),H. assultaGuenée andHeliothis peltigera(Denis & Schiffermüller) were collected as mixed populations from safflower and the wild hostDatura metel, from Patancheru, Andhra Pradesh, India, in 1992 and 1993, and their toxicological responses to insecticides determined. BothHelicoverpa armigerastrains were highly resistant to cypermethrin, fenvalerate, endosulfan and quinalphos insecticides, based on resistance ratios relative to laboratory reared susceptible strains. There was no evidence of resistance development inH. assultaandHeliothis peltigerato the same chemicals. Light trap data collected from 1974 to 1987 showed thatHelicoverpa armigerawas at least 100 × more abundant than the other two species over most of the cropping season. Peak catches ofH. assultaandHeliothis peltigerawere confined to defined times in the season, corresponding with the flowering and fruiting periods of their respective host plants; August-October forHelicoverpa assultaand November-December forHeliothis peltigera. Helicoverpa armigeraon the other hand, because of its high polyphagy on commercial and wild hosts, was abundant between August and April. Resistance has not developed inH. assultaandHeliothis peltigerain southern India, probably because of their restricted host range, limiting exposure to insecticides.