The Selection Of Resistant Strains Of Wheat Aphids To Imidacloprid And Research Of Biochemical Mechanisms Of Resistance

As one important class of pests to economic plants of agriculture and forestry，aphids can cause multiple violations to host plants，which makes the aphids one ofhighly threatened species to agroforestry production.There has no words to say theachievements of pesticides，as one part of the pest control project.but the long-termwidespread use of pesticides has led to resistance developing to the insecticides ofinsects. Resistance of pests makes chemical control work facing big challeng-es.Research of mechanism of resistance of pests becomes important at thistime.Predecessors have made arduous explorations to clarify the mechanism of re-sistance.This experiment tried to elaborate the biochemical mechanisms of re-sistance of Schizaphis graminum to imidacloprid and effects of imidacloprid toecological parameters of S.graminum focusing development of resistance ofS.graminum to imidacloprid and the selective effect of imidacloprid to S.graminumand tracking the dynamic changes of related enzymes of S.graminum.we get resistant S.graminum whose LC50is7.21fold of the sensitive and ac-tivities of acetylcholinesterase and glutathione transferase of the resistant are1.881.31fold of the sensitive respectively. It shows that the resistance of S.graminum toimidacloprid develops slowly by continuous selection of imidacloprid.It also showsthat the activities of acetylcholinesterase and glutathione transferase change withthe LC50，which indicates that resistance of S.graminum to imidacloprid may beassociated with the enhancement of acetylcholinesterase and glutathione transfer-ase.The LC50and activities of acetylcholinesterase and glutathione transferase ofthe first generation was elevated after exposing to the sublethal-dose imidaclopridof S.graminum parents，and returned to pre-treatment levels with the continuationof generations respectively.It shows that the sublethal-dose imidacloprid has in-ducing effect on activities of acetylcholinesterase and glutathione transferase.It al- so shows that the sublethal-dose imidacloprid has inhibition on the average lifespan，daliy amount of nymphs，rm，R0and λ of the parents after exposing to the suble-thal-dose imidacloprid of sensitive S.graminum parents，which will be graduallyreduced with the continuation of generations.