Testing the effect of different insecticides on Myzus persicae (Homoptera: Aphididae) in field mustard (Brassicae campestris L.) Czern for possible consideration in an IPM strategy

Efficacy of insecticides and biological control agents in an Integrated Pest Management (IPM) program requires a full understanding of both these factors and their interactions. With this in mind, a study was conducted to build an IPM strategy to control Myzus persicae (Homoptera: Aphididae) in field Mustard (Brassica compestris) crops using a combination of insecticides and biological control agents. Five different insecticides (methomyl, matrine, carbosulfan, thiamethoxam, and pymetrozine) were used to test the survival of Aphidius matricariae wasps under field and laboratory conditions. Under laboratory conditions five different concentrations (1%, 0.5%, 0.25%, 0.13% 0.06%) along with the control were made of each insecticide. Parasitoids exposed to Pymetrozine showed the highest percent emergence at 82.96%, 65.18%, 64.07%, 53.70% and 46.66% of from mummified aphids followed by thiamethoxam, carbosulfan, matrine and methomyl, whereas under field conditions none of these insecticides showed negative impacts on the emergence of A. matricariae wasps. In the presence of insecticides, no significant effect on emergence of A .matricariae wasps from mummified aphids was observed with pymetrozine showing 90.91% emergence of A. matricariae wasps, carbosulfan 81.25%, matrine 80.27%, thiamethoxam 77.29% and methomyl 75.49% emergence, respectively. In addition to observing the effect of insecticides on the emergence of A. matricariae, efficacy of these insecticides against populations of M. persicae was also studied. In order of efficacy, thiamethoxam > matrine > pymetrozine > carbosulfan > methomyl showing 91.37%, 89.61%, 72.46%, 56.6% and 54.35% reductions in aphid populations, respectively. The results of this study show that a biological control agent together with these insecticides can be used simultaneously as part of an IPM program to control M. persicae in field Mustard.