Effect of some Insecticides on the Parasitoids and Predators of the Cotton Whitefly, Bemisia tabaci Genn.

In an evaluation of the effects of different insecticides against the natural enemies of whitefly, Bemisia tabaci Genn., cotton crop treated with synthetic pyrethroids recorded 9.7 per cent parasitism due to aphelinid and it was on par with endosulfan. Pyrethroids were highly detrimental to the predators, recording the lowest number of 2 to 4.3 of early and 0.3 to 1.2 late occurring predators per 10 leaves. The insecticides of natural origin showed 15.8 to 18.1 per cent parasitoid activity and maintained 3.4 to 7.9 predators/l0 leaves. Triazophos and deltaphos recorded the lowest parasitism and predation levels, whereas fenpropethrin recorded a higher level (14.8 per cent) of parasitism.