INSECTICIDE RESISTANCE IN HELD POPULATION OF AMERICAN BOLLWORMS, Helicoverpa armigera HUB. (LEPIDOPTERA: NOCTUEDAE)

摘要

Insecticide resistance studies on Helicoverpa armigera (Hubner) have been carried out at Insecticide Resistance Management Laboratory of Department of Entomology, Marathwada Agricultural University, Parbhani, Maharashtra (India) to monitor the resistant frequencies in H. armigera during peak cotton growth periods to different groups of insecticides and resistance development during 2005-06 crop season. The resistance monitoring was carried out against cypermenthrin, chlorpyriphos, quinalphos, endosulf an, methomyl and spinosad. Among these, synthetic pyrethroid i.e. cypermethrin have shown high resistance frequencies (84-88%). Moderate resistance frequencies have shown against chlorpyriphos, quinalphos and methomyl. Low resistance frequencies was recorded against endosulfan (25-30%). The population was near about susceptible to spinosad. The LD_(50) values of cypermethrin, chlorpyriphos quinalphos, profenophos, endosulfan, methomyl and spinosad were 1.399, 0.729, 0.680, 0.320, 3.359, 1.515 and 0.0641 mu g/larva, respectively. H. armigera has developed more resistance i.e. 279.80 folds resistance against cypermethrin followed by chlorpyriphos (36.45) and methomyl (11.65). Whereas, only 6.01, 6.09 and 6.27 folds resistance was observed against quinalphos, endosulfan and profenophos, respectively.