Resistance Detection Of Diamondback Moth To Ten Insecticides And Resistant Risk Assessment Of Cyantraniliprole

Diamondback moth,Plutella xylostella,is an important pest of crucifers worldwide.The cost of controlling diamondback moth is extremely high due to its great harm.The annual cost of controlling diamondback moth is as high as 4 billion to 5 billion US dollars in the world.Diamondback moth larvae mainly feed on the leaves of cruciferous plants.In severe cases,the whole leaves are eaten into a net.Diamondback moth itself has the characteristics of short generation,large amount of occurrence,rapid development of resistance and more serious,so it causes greater difficulties in the actual control.In order to effectively control P.xylostella and reduce its damage to vegetable crops,the sensitivity of sensitive strains P.xylostella to ten commonly used pesticides was determined in this paper.Diamondback moth collecting from seven cruciferous vegetable production areas were tested,and the risk of resistance to cyantraniliprole was also determined in this study.The main results are as follows:1.Sensitivie baseline of diamondback moth to ten pesticidesThe susceptibility of releative sensitive strains P.xylostella to 10 commonly used pesticides was measured using the dipping method.The results showed that emamectin benzoate,chlorantraniliprole,and fipronil had higher toxicity against P.xylostella at 48h.The LC₅₀0 values??were 0.17,0.25 and 0.33 mg/L,respectively.Diafenthiuron and beta cypermethrin have relatively low toxicity against P.xylostella among 10 insecticides.The LC₅₀0 values??at 48 h were 24.85 mg/L and 36.72 mg/L,respectively.2.Resistance detection of P.xylostella to ten pesticides in different regionsThis test used the dipping method to determine ten insecticides to P.xylostella collected from seven regions.The result showed that the resistance of diamondback moth population to chlorantraniliprole was at high resistant level,especially the Zengcheng population,which was 6642.12 times resistance ratio.The resistance to cyantraniliprole was less than 5 times in7 regions.The resistance level of 7 regions to diafenthiuron was lower than 10 times?RR?10?.The resistance of Wuxi population to chlorfenapyr was 26.49 times,which was at the middle resistance level?10<RR<100?.Except 29.96 times of Tonghai population and 16.84times of Wuxi population,the resistance to tolfenpyrad was below the low level.In addition to 42.26 times of Tonghai population,26.75 times of Tai'an population and 17.64 times of Weifang population,the resistance to tebufenozide was less than 10 times.Except for 2.11times of Taian population and 3.76 times of Laiwu population,the population of other areas was more than 10 times to emamectin benzoate,and Tonghai population was 95.82 times.In addition to the populations of Zengcheng and Baiyun,the resistance of the populations to indoxacarb in other areas was more than 10 times,and the resistance of Wuxi population was67.57 times.The resistance to fipronil was less than 10 times in Zengcheng,Baiyun and Laiwu,and the resistance to fipronil was moderate in other areas.The three populations of Laiwu,Weifang and Wuxi had moderate resistance to cypermethrin,while the others had low resistance.3.Cyantraniliprole resistance and Resistance Risk AssessmentAfter using cyantraniliprole selecting for 15 generations,the resistance of P.xylostella to cyantraniliprole was 35.89 times.The resistance development from X₀ to X₈ is slow,and the resistance development gradually accelerates after X₉,it has developed to moderate resistance in X₁₅.The threshold trait analysis method was used to study the actual heritability of resistance in P.xylostella,and the development of resistance at different lethal rates was predicted.The results showed that the actual heritability of resistance during the 15 generation selection was 0.209.Assume that the lethality of flubendiamide to P.xylostella is 50%,60%,70%,80%,90%,and the number of generations required to increase its resistance by 10 times has been predicted.At the actual heritability h²=0.209,when 50%to 90%of the individuals in the population are lethal,it takes about 4 to 10 generations to obtain 10 resistant times;When the heritability h²=0.137,it takes about 7-18 generations to obtain 10 resistant times.