关键词: 草地贪夜蛾, 抗药性, 氨基甲酸酯, 拟除虫菊酯, 双酰胺, 靶标基因, 突变频率

Abstract:

【Background】The fall armyworm (Spodoptera frugiperda) is a major migratory agricultural pest in the tropical and subtropical areas of America, it has rapidly expanded to more than 100 countries around the world since 2016, and has now invaded 27 provinces (Autonomous Region, Municipality) in China, posing a great threat to food security. Resistance may become an increasingly serious problem in many regions with the heavy reliance on insecticides for several years and lead to low control efficiency. S. frugiperda had spread to the north of the Great Wall rapidly. However, there are few studies on insecticide resistance and annual variation in China, especially the Great Wall protection zone in 2020 and 2021.【Objective】The objective of this study is to clarify the susceptibility and differences of S. frugiperda populations to insecticides in the Great Wall protection zone and other areas of China, and to provide guidance for scientific insecticide use for the prevention and control of S. frugiperda.【Method】Samples of S. frugiperda were collected from maize fields in 13 provinces (Autonomous Region, Municipality) in China, and the genomic DNA was extracted. The mutations of target genes of carbamate, pyrethroid and diamide insecticides in 362 individuals collected from 47 cities (districts) of 13 provinces (Autonomous Region, Municipality) in 2020 and 2021 were analyzed through direct sequencing of the PCR products individually.【Result】There were 6 genotypes of mutations in ace-1 to carbamate insecticides in all the samples. A201S and F290V mutations were detected in ace-1. The frequency of A201S heterozygous mutation was 8.4%, and the frequency of F290V homozygous and heterozygous mutations was 14.9% and 25.7%, respectively. No G227A mutation was detected. The mutation frequency at F290V in the key prevention region was higher than that in the migratory transition region and annual breeding region, while the mutation frequency at A201S was lower than that in the above two regions. The average frequency of ace-1 mutation was high in the Great Wall protection zone, Huang-Huai-Hai interception zone, Yangtze River Basin and Southwest and South China protection zone. There was no significant difference in the frequency of ace-1 mutation between the populations in 2021 and 2020. No mutations were detected in pyrethroid vgsc and diamide ryr.【Conclusion】A201S and F290V mutations with high frequency in ace-1 is one of the mechanisms conferring carbamate resistance in many populations in China. The use of carbamates should be restricted in the control of S. frugiperda. No mutations had been detected in the vgsc and ryr, suggesting susceptibility to pyrethroids and diamides for rational rotation, however, the low frequency of mutation in S. frugiperda and common mutation in Spodoptera exigua (relatives of S. frugiperda) to pyrethroids and diamides have been detected. In the future, the effect of high insecticide selection stress in the lab and field populations fed by different hosts on the target gene mutation should be evaluated, and the research of rapid diagnostics methods and products of insecticide resistance should be accelerated.

Key words: Spodoptera frugiperda, insecticide resistance, carbamate, pyrethroid, diamide, target gene, mutation frequency