Sublethal Effects Of Three Of Nicotine Insecticides On Microplitis Mediator

Nicotine insecticide is the most widely used insecticide in the world.The environmental compatibility of nicotine insecticides with parasitic natural enemies has been controversial,and has been widely concerned by all walks of life.Therefore,this study comprehensively evaluated the toxicity of the new generation of nicotinic insecticides nitenpyram、sulfoxaflor、flupyrfuranone to the M.mediator.In this study,the acute toxicity and safety evaluation of three new generation of nicotine insecticides to the adult M.mediator were determined by glass tube film method under indoor conditions;the emergence rate,parasitism rate,male female ratio,adult longevity,weight,weight of the three insecticides treated with different sublethal concentrations(LC₁₀,LC₁₅,LC₂₀)were determined by cocoon impregnation method and glass tube film method.The effects of sublethal concentrations of three insecticides on the activities of superoxide dismutase（SOD）catalase（CAT）and phenol oxidase（PO）in adult M.mediator were determined by glass tube film method.In order to better coordinate the relationship between chemical control and biological control,in order to provide a theoretical basis for the protection of natural enemy insects,scientific and effective guidance for the scientific and rational use of chemical pesticides in the field.The results show that:1.The acute toxicity of three insecticides to adult M.mediator.At 24 h,the LC₅₀values of nitenpyram,sulfoxaflor and flupyrfuranone were 0.04,0.03,0.97μg/m L,respectively;at 48 h,the LC₅₀values of nitenpyram,sulfoxaflor and flupyrfuranone were 0.03,0.01,0.19μg/m L,respectively.The toxicity of three kinds of nicotine insecticides to the adult M.mediator was as follows:sulfoxaflor>nitenpyram>flupyrfuranone.From 24 h to 48 h,the safety factor of flupirofuranone was 0.500,0.045,the safety decreased from general to very low;the safety factor of nitenpyram was 0.020,0.015,tthe safety was still very low;the safety factor of flupirfenapyr was 0.018,0.006,the safety was still very low.2.The sublethal effects of three kinds of nicotine insecticides on M.mediator were studied.Compared with the control group,the adult longevity,emergence rate and parasitism rate of the three insecticides treated with sublethal concentrations were significantly reduced.The effects on adult longevity were as follows:sulfoxaflor>nitenpyram>flupyrfuranone.The effects on Emergence rate were as follows:nitenpyram>sulfoxaflor>flupyrfuranone.The results showed that:Compared with the control group,the LC₁₀of nitenpyram decreased by 33.34%,the parasitic rate was nitenpyram>sulfoxaflor>flupyrfuranone,the LC₁₀of nitenpyram decreased by 19.00%compared with the control group,There was no difference in sex ratio between all treatment groups and control group,The effects on adult weight were as follows:flupirone>sulfoxaflor>nitenpyram,and the effects on adult body length were as follows:sulfoxaflor>flupyrfuranone>nitenpyram.3.The effects of adults M.mediator on the activities of three enzymes in sublethal concentration of three kinds of nicotine insecticides.With the increase of sublethal concentration of the three insecticides,the activities of three enzymes were inhibited and showed an increasing trend by sulfoxaflor and flupirofuranone,while the activities of three enzymes were activated first and then inhibited by nitenpyram.Compared with the control group（1544.20 U/g）,nitenpyram LC₁₀and LC₁₅activated 1.80%and 8.80%SOD activities,respectively,while cat and PO activities in LC₁₀treatment group were 0.50%and 11.37%respectively.The effects of sublethal concentrations of three nicotine insecticides on antioxidant enzymes in adult M.mediator were as follows:flupirofuranone>sulfoxaflor>nitenpyram,and the effects on phenoloxidase were as follows:sulfoxaflor>flupirofuranone>nitenpyram.In this paper,the effects of nicotinic insecticides such as nitenpyram,fipronil and flupyrfuranone on the M.mediator were studied,It was found that the three insecticides had high toxicity to the M.mediator,and had certain effects on the emergence rate,parasitism rate,sex ratio and enzyme activity of the M.mediator.Therefore,in agricultural production,we should pay attention to the effect of insecticides on the parasitoid,use the dosage of insecticides reasonably,protect the natural enemies in the field better,combine biological control and chemical control more effectively,and optimize the control effect.