Effect of foliar applications of some insecticides on Bemisia tabaci, predators and parasitoids:: Implications in its management in Pakistan

Three experiments were carried out during three consecutive years to evaluate 19 insecticides and 12 tank mixtures of different groups of insecticides against the whitefly Bemisia tabaci and its predators and parasitoids under field conditions in cotton. In the first experiment, the whitefly population was lower in treatments with thiacloprid an(] higher in those with black warrant (a.i. alcohol) and cypermethrin; the number of predators was higher with Agri-50 and spinosad and lowest with cypermethrin, whereas percent parasitism was higher with thiacloprid and lower with methamidophos. In the second experiment, the whitefly population was lower in treatments with buprofezin, pyriproxyfen and diafenthiuron and higher in those with endosulfan, imidacloprid and thiamethoxam; the number of predators was higher with pyriproxyfen and lower with thiamethoxam, whereas percent parasitism was higher with pyriproxyfen and lower with thiamethoxam. In the third experiment, the whitefly Population was lower in a treatment mixture with buprofezin + fenpropathrin and higher in that with thiamethoxam + chlorpyrifos; the number of predators was higher with buprofezin + fienpropathrin and lower with deltamethrin + triazophos and deltamethrin + chlorpyrifos, whereas percent parasitism was higher with the mixture of pyriproxyfen + chlorpyrifos and lower in imidacloprid + chlorpyrifos, betacyfluthrin + triazophos, and deltamethrin + triazophos. Effective use of these insecticides to manage whitefly infestations and to save predators and parasitoids is discussed.