CSIRO Agriculture and Food, St. Lucia, Brisbane, Queensland, Australia.
Elanco Australasia Pty Ltd, Kemps Creek, New South Wales, Australia.
Pest Manag Sci. 2022 Oct;78(10):4195-4206. doi: 10.1002/ps.7037. Epub 2022 Jul 2.
The sheep blowfly, Lucila cuprina, is a myiasis-causing parasite responsible for significant production losses and welfare issues for the Australian sheep industry. Control relies largely on the use of insecticides. The pyrimidine compound, dicyclanil, is the predominant control chemical, although other insecticides also are used, including imidacloprid, ivermectin, cyromazine and spinosad. We investigated in vitro resistance patterns and mechanisms in field-collected blowfly strains.
The Walgett 2019 strain showed significant levels of resistance to both dicyclanil and imidacloprid, with resistance factors at the IC of 26- and 17-fold, respectively, in in vitro bioassays. Co-treatment with the cytochrome P450 inhibitor, aminobenzotriazole, resulted in significant levels of synergism for dicyclanil and imidacloprid (synergism ratios of 7.2- and 6.1-fold, respectively), implicating cytochrome P450 in resistance to both insecticides. Cyp12d1 transcription levels were increased up to 40-fold throughout the larval life stages in the resistant strain compared to a reference susceptible strain, whereas transcription levels of some other cyp genes (6g1, 4d1, 28d1) did not differ between the strains. Similar resistance levels also were observed in flies collected from the same property in two subsequent years.
This study indicates that in vitro resistance to both dicyclanil and imidacloprid in this field-collected blowfly strain is likely mediated by cytochrome P450, with Cyp12d1 implicated as the enzyme responsible; however, it remains possible that another P450 also may be involved. A common resistance mechanism for the two drugs has important implications for drug rotation strategies designed to prolong the useful life of flystrike control chemicals. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
绵羊狂蝇，Lucila cuprina，是一种引起蝇蛆病的寄生虫，给澳大利亚养羊业造成了重大的生产损失和福利问题。控制主要依赖于杀虫剂的使用。嘧啶化合物双环酰亚胺是主要的控制化学品，尽管也使用其他杀虫剂，包括吡虫啉、伊维菌素、环丙氨嗪和多杀菌素。我们研究了田间收集的狂蝇菌株的体外抗药性模式和机制。
沃格特 2019 株对双环酰亚胺和吡虫啉均表现出显著的抗药性，在体外生物测定中，抗性系数分别为 26 倍和 17 倍。用细胞色素 P450 抑制剂氨基苯并三唑共同处理，双环酰亚胺和吡虫啉的协同作用水平显著（协同比分别为 7.2 倍和 6.1 倍），表明细胞色素 P450 参与了这两种杀虫剂的抗性。与参考敏感株相比，抗性株在整个幼虫期 Cyp12d1 的转录水平增加了 40 倍，而其他一些 Cyp 基因（6g1、4d1、28d1）的转录水平在两个菌株之间没有差异。在随后的两年里，从同一地区收集的苍蝇中也观察到了类似的耐药水平。
本研究表明，在田间采集的狂蝇株中，对双环酰亚胺和吡虫啉的体外抗药性可能是由细胞色素 P450 介导的，Cyp12d1 被认为是负责的酶；然而，另一种 P450 也可能参与其中。这两种药物的共同耐药机制对旨在延长蝇蛆病防治化学品有效寿命的药物轮换策略具有重要意义。© 2022 作者。害虫管理科学由约翰威立父子公司代表化学工业协会出版。
