Acharya Ranga N.G.Ranga Agricultural University, Regional Agricultural Research Station, Lam, Guntur-522034, Andhra Pradesh.
Bioassay studies conducted during 1988–89 season to determine the insecticide resistance in Helicoverpa armigera of Guntur strain compared to Srikakulam strain showed that Guntur strain has developed 18.2 fold to monocroptophos, 10.82 fold to cypermethrin, 10.56 fold to endosulfan, 9.36 fold to carbaryl, 1.78 fold to quinalphos and 1.09 fold to chlorpyriphos. The results clearly indicated the need for the development of insecticide resistance management strategy for Helicoverpa in Andhra Pradesh.
