Effect of continuous exposure of insecticides on the developmental biology of diamondback moth Plutella xylostella L. (Lepidoptera: Yponomeutidae)

The effect of selection pressure of endosulfan, deltamethrin and cypermethrin was studied on the duration and morphometrics of diamondback moth, Plutella xylostella (L.). The selection pressure of test insecticides adversely affected the dimensions of different developmental stages of P. xylostella. Similarly the size of the adults of selected strains was significantly less than that of parent generation and the non-selected strain. The longevity of male and female adults reared under control was found to be higher than individuals reared under selection pressure for eight generations. The incubation period of the cypermethrin-selected strain was shorter (3.80 days) than the parent generation (4.10 days) and those individuals reared under no selection pressure (4.60 days).