Toxicity Of Insecticides To Black Cutworm Agrotis Ypsilon(Rottemberg) And Safety Evaluation To Soil Organisms

In order to screen for pesticides which is efficient to black cutworm and low-toxic toenvironment, the laboratory toxicity to17insecticides in the2-instars,3-instars and4-instarsBlack Cutworm （Agrotis ypsilon） was determined by leaf-dip method; the synergism of PBO、TPP、SV1、DEM to insecticides on the black cutworm were studied;evaluate insectdevelopment after treatment of chlorpyrifos was studied, meanwhile,we studied the efficienceto black cutworm and low-toxic to earthworms and soil microorganism and the effect of mainpesticides in greenhouse. The results were as follow.1.the virulence of Fipronil, Ethiprole, Indoxacarb, Emamectin benzoate and Chlorfenapyr wassignificantly higher than that of Chlorpyrifos, phoxim, pleocidin, cyhalothrin and so on. Thetoxicity of Fiproni was the highest, who’s LC₅₀was0.27. Different instars of black cutwormto the pesticides resistance significantly different. With increasing age, the insect resistanceincrease apparently.2.The experiment of interaction of enzyme inhibitors with insecticides indicated that fourdifferent enzyme inhibitors showed obvious restraint to indoxacarb （synergism ratiobetween0.25and0.96）. And four different enzyme inhibitors showed synergism to methomyl,chlorfenapyr,emamectin benzoate and tebufenozide on S. exigua, synergism ratio between1.3and16.23.3.In order to correctly evaluate insect development after treatment of chlorpyrifos, we fedlarvae with artificial diets treated with low concentrations of CPF. The results showed thatlow concentrations of CPF could stinulate the growth of insect significantly and increasepupal weight. For larvae treated with CPF at10μg/kg, larvae weight on the3rdday andpupal weight increased by86.4%and28.6%respectively. Low concentrations of CPFimproved the growth rate and shortened larval periods of Agrotis ypsilon compared with thecontrol larval periods was reduced by about2.0±0.07d in larvae fed with diet containing10μg/kg CPF. 4. Leaf-dip method, artificial soil method and direct absorption method were conducted todetermine the laboratory toxicity of six insecticides to the Black Cutworm （Agrotis ypsilon）,the acute response to the earthworm （Eisenia foelida） and the effects on respiration of soilmicroorganism, respectively. Results showed that the toxicity of Fipronil, indoxacarb andemamectin benzoate was significantly higher than that of chlorpyrifos, phoxim andlambadacyhalothrin. The acute response to the earthworm results showed that the LC₅₀ofFipronil, indoxacarb and emamectin benzoate was1320.80,1153.42and167.91mg/kg, whichbelonged to the inferior toxic category. The selective toxicity of Fipronil was the highestamong6insecticides tested, and its selective toxicity ratio reached7115.23. Results alsoshowed that these pesticides all belong to the lower poisonous pesticide category on soilmicrobe.5. The greenhouse experiment results showed that4days later, the Control Efficacy ofFipronil by spray, seed dressing applicator control efficiency of88.88%,50%and77.78%，control efficiency of the spray was significantly higher than seed dressing anti-efficiency, andcontrol efficiency higher than80%.The control efficiency Indoxacarb by three kinds Methodswas83.33%,38.88%and61.12; control efficiency of the spray was also significantly higherthan the other two spraying methods. Emamectin benzoate’s spray control efficiency as highas96.11%, significantly higher than the two other spraying methods, while the control effectof seed dressing and applicator was no significant difference. Phoxim as the effect of thegranule applicator is higher than the other two spraying; chlorpyrifos applicator effect wassignificantly higher than the spray and seed dressing. Three of the beta-cypermethrin waysto control black cutworm larvae effects are poor, but the spray is better for72.22%.