河北地区番茄潜叶蛾田间种群对五种杀虫剂的抗性监测OA

[Aim]To clarify the resistance status of Tuta absoluta to five insecticides(lambda-cyhalothrin,indoxacarb,spinetoram,broflanilide and cyproflanilide)in Hebei Region,North China.[Methods]Leaf-dipping method was used to determine the median lethal concentration(LC50)values of the above five insecticides against the 2nd instar larvae of the field-collected populations of T.absoluta during 2023-2025.These populations were sampled from tomato plants in greenhouses or open fields across Hebei Province,including Economic Development Zone of Zhangjiakou,Chongli District of Zhangjiakou City,Fengning Manchu Autonomous County of Chengde City,Pingquan City of Chengde City,Qinglong Manchu Autonomous County of Qinhuangdao,Luanzhou City of Tangshan City,Xianghe County of Langfang City,Gu'an County of Langfang City,Rongcheng County of Baoding City,Raoyang County of Hengshui City and Feixiang District of Handan City.The resistance levels of the 11 field populations to the five insecticides were evaluated based on the LC50 values.Point mutations(M918T,T929I and L1014F)in the sodium channel knock-down resistance(kdr)gene in T.absoluta larvae of the susceptible strain were detected using the PCR amplification followed by gene sequencing.[Results]T.absoluta populations from 11 regions in Hebei Province showed high susceptibility to lambda-cyhalothrin,spinetoram,broflanilide and cyproflanilide,but exhibited varying degrees of resistance to indoxacarb.Notably,the populations collected from Economic Development Zone of Zhangjiakou City and Qinglong Manchu Autonomous County of Qinhuangdao City in 2023 showed the highest resistance to indoxacarb,reaching high-resistance levels with the resistance ratios of 60.9 and 56.3,respectively.Although the resistance ratios of the 11 field populations to lambda-cyhalothrin remained low(only 0.4-2.3),the LC50values of lambda-cyhalothrin against the 2nd instar larvae of all populations(including the relatively susceptible strain)in 48 h were notably high,ranging from 178.141 to 953.106 mg/L.Moreover,the mutation frequencies of the M918T,T929I and L1014F sites in kdr of the relatively susceptible strain were 20.0％,25.0％and 100.0％,respectively.[Conclusion]Spinetoram,broflanilide and cyproflanilide are recommended for controlling T.absoluta in Hebei Region.To delay the development of resistance,these insecticides should be rotated with other insecticides exhibiting different modes of action or integrated with other control measures.