| Spodoptera frugiperda(Lepidoptera: Noctuidae)is native to tropical and subtropical areas of the Americas,invaded Yunnan Province from December 2018 to January 2019,invaded Huangshan City in May 2019,and hazards have been detected in Anhui Province.S.frugiperda has the characteristics of the wide host range,strong reproductive capacity,long-distance dispersal and migration,and high levels of resistance,It has been found that S.frugiperda has developed a high level of resistance to a variety and currently used of insecticides,including chlorantraniliprole,indoxacarb,spinetoram and emamectin benzoate.It is very urgent and important to strengthen the monitoring of resistance of the S.frugiperda to commonly used insecticides and screen out rotational agents which can effectively control S.frugiperda.Therefore,this thesis studies the monitoring of drug resistance and the screening of control agents for S.frugiperda in Anhui Province,which is expected to provide guidance for the scientific prevention and control of S.frugiperda.The specific research conclusions were as follows:1.Changes in the sensitivity of S.frugiperda to indoxacarb and spinetoram in different regions of Anhui Province.In order to clarity the incidence of resistance of S.frugiperda in Anhui Province,this study used insecticide artificial diet incorporation assay method for two consecutive years in 2020 and 2021 to determine the resistance level of indoxacarb and spinetoram in six regions of Anhui Province.The results of the study found that the population of S.frugiperda in six regions of Anhui Province was sensitive to indoxacarb and spinetoram.The resistance to indoxacarb is between 0.81 and 3.55 times,and the resistance to spinetoram is between 1.11 and 2.25 times.The result from 2021 and 2020 showed a slight increase in resistance levels in most regions of indoxacarb and spinetoram,but no significant differences.Therefore,indoxacarb and spinetoram can continue to be used to control S.frugiperda in Anhui Province.2.Indoxacarb and spinetoram targets mutations of the S.frugiperda in different parts of Anhui Province.Used by molecular biology detection technology to mutation detection of Voltage-gated sodium channel(VGSC)and Nicotinic acetylcholine receptors(n ACh Rs)genes in 2020and 2021 in six regions of Anhui Province.The study found that in 120 individuals in 6 populations of S.frugiperda in 2020 and 2021,VGSC was not detected at the F1845 and V1848 sites,and n ACh Rs were not detected at the G275 amino acid site for two consecutive years.The results showed that the S.frugiperda,which invaded six regions of Anhui Province,did not carry mutations of related to resistance to indoxacarb and spinetoram.3.Determination of the virulence of metaflumizone in combination with indoxacarb and chlorantraniliprole respectively on S.frugiperda.In this study,the toxicity of the 3rd instar larvae of S.frugiperda by insecticide artificial diet incorporation assay method,and the joint virulence of metaflumizone in combination with indoxacarb and chlorantraniliprole respectively by co-toxicity coefficient method.The screening found that the synergistic effect was strongest when the equivalence ratio of metaflumizone and indoxacarb was 1:9,the co-toxicity coefficient(CTC)was 161.17;and the equivalent ratio of metaflumizone and chlorantraniliprole was 3:7,the synergistic effect was strongest and the CTC was 335.62.The results showed that the compounding of metaflumizone with indoxacarb and chlorantraniliprole respectively had a synergistic effect.4.The field effectiveness of mixture of metaflumizone with indoxacarb and chlorantraniliprole respectively of S.frugiperda.According to the laboratory joint virulence screening results,carried out the field control efficacy of the metaflumizone with indoxacarb and chlorantraniliprole respectively was verified.The 22% metaflumizone suspension agent and the 150 g/L indoxacarb suspension agent were mixed with a 50% reduction,which field control efficacy of S.frugiperda for 1d,3d and 7d reached 77.73%,86.01%,93.16% respectively.The 22% metaflumizone suspension agent and the 200 g/L chlorantraniliprole suspension agent were mixed with a 50% reduction,which field control efficacy of S.frugiperda for 1d,3d and 7d reached 84.54%,92.98%,94.65% respectively,which higher than the control single agent of 22% metaflumizone suspension agent,150 g/L indoxacarb suspension agent,200 g/L chlorantraniliprole suspension agent.The results show that the compounding of metaflumizone with indoxacarb and chlorantraniliprole respectively have a reducing and increasing effect in the control S.frugiperda. |
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