Effects Of Sulfoxaflor Stress On Reproductive Characteristics And Population Parameters Of A.gifuensis

The green peach aphid（Myzuspersicae）is one of the most destructive pests in the world.At present,the control of green peach aphid is mainly based on chemical control.However,due to the extensive use of pesticides,the green peach aphid has developed resistance to many insecticides.Prevention is becoming more and more difficult.A.gifuensisas the dominant parasitic natural enemy of M.persicae,and plays an important role in pest control.However,during the process of chemical control of M.persicae,the A.gifuensis in the same habitat is subject to the recommended dosage and residue of pesticides in the field.The virulence of the drug is inevitable.The degree of virulence of insecticides on natural enemies is the prerequisite for chemical control and biological control.Therefore,in this study,the new insecticide sulfoxaflor was used as the test agent,and the toxicity and safety evaluation of the agent to M.persicae and A.gifuensis were carried out,and the recommended dosage of sulfoxaflor to control aphids in the field was used as the test.The effect of insecticides on the reproduction and population development of A.gifuensiswas measured under laboratory conditions,and the effects of insecticidesplantresidues on the parasitic ability of natural enemies was measured at the same time,which provided scientific basis and technical reference for the coordination of chemical control and biological control in the comprehensive management of M.persicae.The main results were as follows:1.The relative virulence of sulfoxaflor against M.persicaeand A.gifuensiswas measured by the leaf impregnation method and acute toxicity method respectively.The results show that The LC50 of sulfoxaflor to M.persicaeand A.gifuensiswas0.19ug/m L and 35.41ug/m L respectively.The toxicity of pesticides to the two insects was remarkablely different,the safety evaluation results indicated that safety factor of sulfoxaflor against A.gifuensiswas 1.18-1.77,which was low toxicity,and the toxicity ratio was 186.37,which was strong safety.2.The adult A.gifuensis was treated for 24h with the recommended dosage of sulfoxaflor for aphid control as the concentration.The results showed that the treatment of sulfoxaflor had an adverse effect on the longevity and reproduction of the surviving individuals.The treatment of insecticide longevity of female and male was13.84d and 6.95d respectively,which was significantly lower than 17.33d and 9.67d of the control group;The treatment of sulfoxaflor total single female eggs and oviposition days were 407.26 grain/head and 12.42d,which were notably lower than449.58 grain/head and 13.90d of the control group;The adverse effects of pesticideson A.gifuensis were mainly concentrated on the first three days after the insecticides treatment;The emergence of sulfoxaflor treatment was 87.8.%,significantly lower than 94.45%of the control group.3.Using sulfoxaflor to A.gifuensis for two consecutive generation and compiled the life-table of the second generation contamination individuals.The results showed that A.gifuensis population dynamics was obviously inhibited by sulfoxaflor treated for two consecutive generation.The treatment of insecticides adult lifespan and total lifespan were 14.80d and 23.80 d respectively,which were evidently lower than that18.95d and 27.68d of the control group;The intrinsic growth rate、weekly growth rate and net reproductive of pesticides treatment were 0.44 d^-1、1.56 d^-1and 316.10grains/female respectively,which were markedly lower than 0.47 d^-1、1.60 d^-1 and406.75 grains/female control group.4.The effects of the plant residue of sulfoxaflor on the leaves to A.gifuensiswere tested under laboratory condition.The residue of pesticides on the leaves will have an adverse effect on reproduction and longevity of the A.gifuensis,which gradually disappears with the extension of the residual period.Among which the first three days the female lifetime、total single female eggs、oviposition days and emergence rate were all lower than those of the control group,From the 5th day the longevity、fecundity and emergence rate of A.gifuensis increased with the prolongation of residue,but there was no notably difference compared with the control group.In conclusion,Sulfoxaflor is safer with a low toxic to A.gifuensis;The sulfoxaflor applied in the field will have certain lethality to A.gifuensisin thehabitat,and the fecundity and lifespan of surviving individuals will be significantly descreased,but the population can still be reproduced for generations;The adverse effects gradually disappeared with the prolongation of pesticides residue on the plant.