Sublethal Effects Of Five Biopesticides On The Predator Aphidoletes Aphidimyza(Rondani)

As an important predative enemy,Aphidoletes Aphidimyza?Diptera:Cecidomyiidae?is prey on aphids It has strong reproductive capacity,is prey on aphids It has strong reproductivecapacity,short generation cycle,and is suitable for large-scale.At present,the pesticide control of Myzus persicae?Sulzer?is mainly spray,which has a great side effect on natural enemies.In order to grasp the toxicity and sublethal effects of commonly used biological pesticides in tobacco fields on aphid gall midge,this study determined five biopesticides matrine,rotenone,spinosad,Bacillus thuringiensis,Emamectin benzoate With regard to the toxicity and safety evaluation of five biological pesticides on A aphidimyza.The sublethal effects of 5 biological pesticides on A aphidimyza,were studied in order to provide technical guidance for the joint control of M persicae.,The main results are as follows.1.Safety evaluation and toxicity determination of 5 biopesticides to Myzus persicae?Sulzer?and Aphidoletes aphidimyza?Rondani?To screen safety biopesticides to Aphidoletes aphidimyza?Rondani?in tobacco fields,the toxicities of 5 kinds of biopesticides on wingless of Myzus persicae and three instars of Aphidoletes aphidimyza?Spray method?,adults of Aphidoletes aphidimyza?The residual film method?,and the safety to the Aphidoletes aphidimyza,was also evaluated.The results showed that the highest toxicity on M.persicae was emamectin benzoate and matrine both at 24 h and 48 h,with LC₅₀ being 2.166 mg/L and 3.695mg/L?24 h?,1.567 and 2.874 mg/L?48 h?,the highest toxicity on larva of Aphidoletes aphidimyza was rotenone,with LC₅₀ being 18.137 mg/L?24 h?and13.771 mg/L?48 h?,the highest toxicity on adults of Aphidoletes aphidimyza was spinosad,with LC₅₀ being 7.249 mg/L?24 h?,4.125 mg/L?48 h?.According to the safety coefficient,rotenone and spinosad are medium-risk and high-risk pesticides against A aphidimyza,;matrine and Bacillus thuringiensis are between medium-risk and low-risk,and Emamectin benzoate is low-risk biopesticides.2.Effects of Sublethal of biopesticides on Predation of Aphidoletes aphidimyza?Rondani?We utilized sublethal doses of 5 bioinsecticides,rotenone,spinosad,matrine,emamectin benzoate and bacillus thuringgiensis,and studied the changes of predatory capacities,functional response predator-prey model,and searching efficiency on A aphidimyza,by the two models of stomach poisoning and contacting toxicity.The results showed that,the functional response models of preying on A aphidimyza were still conformed to Holling's type?curve in spite of pretreated with sublethal doses of 5 biopesticides;while the parameters of models had some changes.The discovery the maximal predatory capacities reduced,handling time prolonged,rates and searching efficiency decreased.And it is related to the way and concentration of the A aphidimyza,at low concentrations,the theoretical predation of the emamectin benzoate?Eb₁-LC₅?in the contact group and the Bacillus thuringiensis?Bt₂-LC₅?,spinosad?S₂-LC₅?and emamectin benzoate?Eb₂-LC₅?in the poisoning group is slightly higher In the control group,increased by 2.72%,4.19%,2.82%and 0.55%respectively.In the contact group,the maximum attack rate of spinosad?S₁-LC₅?was0.5163,and the minimum attack rate of rotenone(R₁-LC₂₅)was 0.4499,which was a corresponding decrease of 12.4%and 23.67%relative to the attack rate of CK of0.5894.After treatment at higher concentration,the time to process prey is longer than CK,rotenone(R₁-LC₂₅,R₂-LC₂₅),matrine(M₁-LC₂₅,M₂-LC₂₅),spinosad(S₂-LC₂₅,S₁-LC₂₅)were extended by 25.59%,38.03%;19.65%,20.56%%;13.25%,15.45%.3.Effects of sublethal concentrations of five biopesticides on life table of experimental populations of Aphidoletes aphidimyza?Rondani?In order to investigate the sublethal effects of five biopesticides on the A aphidimyza.this article uses spraying method to the A aphidimyza.and uses the bisexual life table to study the impact of biopesticides on the growth and reproduction of F1 generations.The results showed that the five biopesticides had no significant effect on the developmental period of the larvae of A aphidimyza.The results showed that:the eggs,1st,2nd,3rd,and pupal developmental period of 5 biological pesticides and 3 sublethal concentrations of the aphid gall midge were not significantly different from those of CK.With the increase of the concentration of the same biological pesticide,the developmental duration of the larvae is prolonged;the developmental duration of the pupae is prolonged under the three concentrations of rotenone,matrine and emamectin,but there is no significant difference from the control;The life span of the female and male adults is shortened,the egg laying period and the number of eggs of the female adults decrease and show significant differences,and the pre-oviposition and total pre-oviposition are prolonged.Under the five biological pesticide treatments,the intrinsic growth rate?r?and weekly growth rate???of the F1 generation were lower than the control treatment,and the difference was not significant;the average generation period?T?between the treatments was close to that of the control group.For the same biological pesticide,as the concentration increases,the corresponding intrinsic growth rate?r?,weekly growth rate???and net value-added rate?R0?gradually decrease.Compared with the control group,only the net value-added rate?R0?)Is a significant difference.