Indoxacarb resistance-associated mutation of Liriomyza trifolii in Hainan, China

Liriomyza trifolii, which has been recently prevalent in China, harms more than 300 plant species, especially cowpea in Hainan. This pest also affects the quality and production of vegetables in winter. Indoxacarb is the first commercial oxadiazine pesticide, which is a new efficient insecticide used to control pests of Diptera, including L. trifolii. The unique mechanism of indoxacarb is that indenyl is transformed into N-demethoxycarbonyl metabolite (DCJW) in insects and acts on inactivated sodium channel; DCJW could then destroy the conduction of nerve impulses, which leads to movement disorders, feeding stoppage, paralysis, and eventually the death of pests. The field population of L. trifolii developed resistance by 769 times higher than the sensitive population in Sanya, Hainan. Results revealed the existence of a mutation (i.e., V1848I) in the sixth transmembrane segment of Domain IV of the sodium channel in the field population. The homozygous resistant genotype frequency for the V1848I mutation was 10-15% among the three field-collected populations. This paper reports for the first time the presence of the kdr mutation V1848I in resistant populations of L. trifolii to indoxacarb. The present study will contribute to the understanding of the evolution of indoxacarb resistance and contribute to the development of resistance management practices for winter vegetables in Hainan.

Automated summary

Liriomyza trifolii, a pest recently prevalent in China, has caused harm to over 300 plant species, particularly cowpea in Hainan. The field population of L. trifolii has developed high resistance to the insecticide indoxacarb, with a mutation in the sodium channel being responsible for this resistance. This study is significant for understanding the evolution of resistance and developing resistance management practices.