Study On The Response Of Aphis Gossypii Glover To Flonicamid Stress

The Aphis gossypii Glover is one of the main pests to pepper.The nymphs and adults harm the tender branches,young leaves,flowers and young fruits of pepper trees.When it occurs in large numbers,the tree strength decreases seriously,affecting the photosynthesis of leaves,thus reducing the fruit setting rate of pepper trees,and seriously affecting the yield and quality of pepper.At present,the control of Aphis gossypii Glover mainly depends on chemical agents.However,the Aphis gossypii Glover developed different degrees of resistance to chemical agents due to unreasonable use of chemical agents for a long time.As the latest generation of insecticides against aphids,flonicamid showed good control effect in the field.However,at present,there are no relevant reports on the development of resistance to flonicamid and the detoxification and metabolism mechanism of P450.Therefore,taking Aphis gossypii Glover as the research object,this paper explored the population dynamics of Aphis gossypii Glover on pepper and the effects of different insecticides on the virulence of Aphis gossypii Glover.Taking 13 generations of Aphis gossypii Glover treated with flonicamid as the material,the dynamic changes of related detoxifying enzyme activity and relative expression of P450 gene were monitored after chemical treatment,to clarify the expression and change law of flonicamid on P450 related genes of Aphis gossypii Glover,To provide a theoretical basis for the scientific control of Zanthoxylum bungeanum aphid and the rational use of flonicamid.The main results are as follows:1.The results showed that the occurrence dynamics of Aphis gossypii Glover showed a double peak pattern,the first growth peak was in the middle of May,and the second growth peak was in early July.The natural enemies followed the population growth of Aphis gossypii Glover and inhibited the growth of Aphis gossypii Glover to some extent.2.The toxicity of different insecticides to Aphis gossypii Glover was measured by dipping method,among which avermectin had the highest toxicity to Aphis gossypii Glover with LC₅₀value of 0.31 mg/L.Meanwhile,it was also found that treatment with avermectin could lead to wing type differentiation in the offspring of Aphis gossypii Glover.The toxicity of beta-cyhalothrin to Aphis gossypii Glover was the lowest with LC₅₀of 364.22 mg/L.Fludinamide(LC₅₀value 25.55 mg/L)showed good insecticidal activity in the effective insecticide.3.The main detoxifying enzyme activities of F13 generation and sensitive strains were studied.The results showed that the enhancement of carboxylesterase and cytochrome P450monooxygenase activities was an important mechanism for Aphis gossypii Glover to deal with fluridamide stress.4.RT-q PCR was used to detect the expression differences of 8 P450 genes in Aphis gos sypii Glover.sensitive lines treated with fluridamide at different time periods.The results sho wed that the expression levels of CYP6CY7 and CYP4CJ1 were significantly higher than tho se of the control group at 48 h and 72 h after fluridamide treatment,and there was no signific ant difference between the control group and the other time periods.CYP6UN1 gene showed a downward trend.The expression level of CYP4CH1 gene was not significantly different fro m that of the control group at different time nodes after treatment with fludinamide.5.The expression of 6 related detoxification P450 genes of F₁₃generation and susceptib le strains was analyzed.The results showed that the expression levels of CYP380C6 and CY P6DA1 were significantly increased after 12 h and 24 h treatment,which were 53 times,6.25times,23 times,29 times as those of the control group,respectively.CYP6CY12 and CYP6D B1 gene treatment for 48 h and 72 h were（15.99 and 4.12 times）and（1.52 and 2.58 times）h igher than those of the control group,respectively,showing significant differences.CYP4CJ1gene expression at 1 h,24 h and 72 h was significantly lower than that in the control group.CYP6CY7 gene treatment for 6 h,12 h,24 h and 72 h were 2.68 times,17 times,10.77 times and 1.38 times of the control group,respectively,which were significantly increased.Combined with the above results,the occurrence dynamics of Aphis gossypii Glover sh owed a bimodal pattern,and flonicamid showed good insecticidal activity in the effective ins ecticide.Flonicamid treatment could affect the changes of related detoxification enzyme acti vity and the relative expression levels of different P450 genes of Aphis gossypii Glover.In or der to reveal the response of Aphis gossypii Glover to flonicamid stress,flonicamid treatment showed good insecticidal activity.The scientific control of Aphis gossypii Glover of Zantho xylum and rational use of flonicamid provided theoretical basis.