Master (M.S.) Program for Plant Medicine, National Taiwan University, Taipei City 10617, Taiwan.
Department of Entomology, National Chung Hsing University, No. 145 Xingda Rd., South Dist., Taichung City 40227, Taiwan.
Pestic Biochem Physiol. 2024 Aug;203:106001. doi: 10.1016/j.pestbp.2024.106001. Epub 2024 Jun 27.
Diamondback moth (DBM, Plutella xylostella) is the most significant pest of cruciferous vegetables as they rapidly develop high-level resistance to many insecticides. Monitoring DBM susceptibility and target-site mutation frequency is essential for pest control. In this study, 10 insecticides were tested on 11 field populations. Frequencies of target-site mutations (including para, ace1, Rdl1, RyR1, and nAChRα6 genes) were estimated by pyrosequencing. Insecticides registered after 2007 for DBM control in Taiwan, i.e., spinetoram, chlorantraniliprole, chlorfenapyr, metaflumizone, and flubendiamide, showed >80% mortality toward several populations; Bacillus thurigiensis, emamectin benzoate, and chlorfluazuron showed medium to low efficacy in all populations; and tolfenpyrad and mevinphos were highly ineffective. Susceptibility to insecticides varied substantially among populations: eight out of nine populations were highly susceptible to spinetoram, but only one was susceptible to flubendiamide. Target-site mutations related to organophosphates, pyrethroids, fipronil, and diamides were detected in all populations, but there were few spinosad and spinetoram mutations. Our three-year field study demonstrated rapid efficacy loss for all insecticides tested, particularly for more toxic insecticides. Skipped-generation selection of a field DBM strain to emamectin benzoate, metaflumizone, chlorantraniliprole, and flubendiamide revealed that mortality rates dropped from 60 to 80% to <10% after 6 generations. Next-generation sequencing was performed to identify possible target gene mutations. A resistance management program that considers the instability of resistance to some chemicals and pertinent data on resistance mechanisms should be established. Identifying compounds to overcome high-frequency field DBM point mutations could be beneficial for pest control.
小菜蛾（DBM，Plutella xylostella）是十字花科蔬菜最重要的害虫，因为它们会迅速对许多杀虫剂产生高水平的抗性。监测 DBM 的敏感性和靶标突变频率对于害虫防治至关重要。在这项研究中，对 11 个田间种群进行了 10 种杀虫剂的测试。通过焦磷酸测序估计了靶标突变（包括 para、ace1、Rdl1、RyR1 和 nAChRα6 基因）的频率。2007 年后在台湾登记用于防治 DBM 的杀虫剂，如 Spinetoram、氯虫苯甲酰胺、氯氟氰菊酯、甲氧虫酰肼和氟苯虫酰胺，对几种种群表现出>80%的死亡率；苏云金芽孢杆菌、甲氨基阿维菌素苯甲酸盐和氯氟脲对所有种群表现出中等到低的功效；而涕灭威和乐果则非常无效。杀虫剂对种群的敏感性差异很大：9 个种群中有 8 个对 Spinetoram 高度敏感，但只有 1 个对氟苯虫酰胺敏感。所有种群都检测到与有机磷、拟除虫菊酯、氟虫腈和二酰胺类杀虫剂相关的靶标突变，但很少有与 Spinosad 和 Spinetoram 相关的突变。我们为期三年的田间研究表明，所有测试的杀虫剂都迅速失去了功效，尤其是对毒性更强的杀虫剂。对田间小菜蛾对甲氨基阿维菌素苯甲酸盐、甲氧虫酰肼、氯虫苯甲酰胺和氟苯虫酰胺进行的 6 代连续选育，发现死亡率从 60%至 80%降至<10%。进行了下一代测序以鉴定可能的靶标基因突变。应建立一个考虑到一些化学品的抗性不稳定性和抗性机制相关数据的抗性管理计划。确定克服高频率田间小菜蛾点突变的化合物可能对害虫防治有益。
