Level of resistance of diamondback moth (Lepidoptera: Plutellidae) to certain commonly used insecticides in Marathwada region of Maharashtra

Larvae and pupae of diamondback moth, Plutella xylostella L. collected from the intensive crucifer growing areas of Aurangabad, Jalna and Parbhani districts of Marathwada region were reared in the laboratory of the Department of Entomology, Marathwada Agricultural University, Parbhani during 1998–99 to study the toxicity of endosulfan, monocrotophos and cypermethrin to F₁ and F₂ generations. The resistance ratio (RR) varied from 2.92 to 4.25, 1.89 to 2.27 and 1.89 to 3.11 for endosulfan, monocrotophos and cypermethrin, respectively among the districts surveyed.