EFFECT OF HOST PLANTS ON THE SUSECPTIBILITY OF THE GREEN PEACH APHID Myzus persicae(Sulzer)TO INSECTICIDES

The green peach aphid Myzus persicae(Sulzer)is a major pest on vegetables,crops and peach in China.The nymphs of the aphid were reared for two successivegenerations on five different hosts viz. lettuce(Lactuca sativa),crowndaisy chrysnathemum(Chrysanthemum coronarium),tobacco(Nicotiana tabacum,Linn.),mustard(Brassicaalboglabra Bail.)and radish(Raphanus sativus L.)to study the effects of hostplants on the suseeptibility to insecticides.Results of laboratory experiments showedthat when sprayed with 0.39 % of rotenone(isolated from Derris root),the aphidsfeeding on radish were the most tolerant to this botanical insecticide,while thosefeeding on lettuce were the most susceptible to this insecticide. Treatment withdimethoate showed similar results.Possible mechanism for the responses to the twoinsecticides,induced by food plants and their sigificances to field application ratesin relation to IPM program were discussed.