Effect of Insecticides on the Population of Aphids, Natural Enemies and Yield Components of Wheat

Field experiment was conducted at Agricultural Research Institute-Tarnab Peshawar, KPK to determine the effect of different insecticides on the population of wheat aphids, its natural enemies and yield, yield components of wheat. Two wheat varieties, one susceptible and one "partially resistant" against aphids, were sown in a randomized complete block design in split plot arrangement, in three replicates. Varieties were kept in the main plots, while subplots received four insecticides, Thiamethoxam 25 GW at the rate of 24 g acre,(-1) Imidaclopride 20% EC at the rate of 70 ml acre,1 Acetamiprid 20 SP at the rate of 150 g acre,(-1) Orange peel extract at the rate of 2500 ml acre In main plot one plot was kept as control. In the sprayed plots the aphids infestation was reduced compared to control. The synthetic insecticides had sharply decreased aphids population, compared to orange peel extract plots where less aphid reduction was noticed. Wheat grain yield and yield parameters like thousand grain weight and number of grains per spike were improved in Imidaclopride treated plots compared to other treatments. If a cultivar is "partially resistant" the damage suffered by aphids should be lower than the damage suffered by a "susceptible". However, when both were treated with selective insecticides; Saleem-2000, suffered less damage compared to Pirsabak-2004. Host plant defense and natural enemies should be a good IPM package against wheat aphids. But in case of aphids population build up and to avoid economic losses selective insecticides should be applied to control wheat aphids.