Mixture of Imidacloprid and Cypermethrin:Its Joint Action and Field Efficacy

Laboratory bioassay and field experiments were conducted to examine the joint action of the mixture of imidacloprid and cypermethrin, two insecticides with different mode of action and spectrum, and to evaluate its efficacy to aphids and small cabbage white on cruciferous vegetables. In bioassay, synergistic action was found with a mixture of the two insecticides to Aphis craccivora, but just additve action to small cabbage white, Pieris rapae. The mixture, applied at 18.75~37.5g a.i./ha, provided good to excellent control of both aphids and small cabbage white in plot trials, which conducted at two separate sites. In contrast, imidacloprid (15g a.i./ha) and cypermethrin (30g a.i./ha) could only control one of the two pest insects.