Department of Entomology, College of Agriculture, Orissa University of Agriculture & Technology, Bhubaneswar-751 003, Orissa, (India).
1Department of Entomology and Agricultural Zoology, Banaras Hindu University, Varanasi-221 005, Uttar Pradesh, (India).
Pyrethroid resistance in the larvae of Heliothis armigera (Hübner) at Varanasi showed two peaks during 1995–97. Higher resistance peaks were recorded in early season collections during October followed by a decline in the successive winter months with a second but small peak during March. Resistance status towards pyrethroids in this non-insecticide use as also non-cotton growing region is somehow comparable with that of focal insecticide used cotton growing regions of the country like Guntur (Andhra Pradesh) and Hisar (Haryana). Involvement of multiple resistance mechanisms was suspected in these populations which varied in different seasons of the year. A kdr and super kdr type of mechanism was suspected as pyrethroid resistance mechanism in populations collected during February and March from Hisar and Varanasi, respectively, was evident in vitro esterase studies as well as with some esterase and mfo inhibitors.
