Department of Entomology, Comstock Hall, Cornell University, Ithaca, New York, USA.
Bayer Animal Health, 12707 Shawnee Mission Parkway, Shawnee, Kansas 66216, USA.
Pestic Biochem Physiol. 2019 Jul;158:61-68. doi: 10.1016/j.pestbp.2019.04.006. Epub 2019 Apr 20.
Insecticide resistance in house fly populations is a major problem faced by livestock producers worldwide. A survey of insecticide resistance levels and pyrethroid resistance allele frequencies in the United States was conducted in 2008-09, but little is known about how resistance levels have changed over the last 10 years. In addition, new target-site pyrethroid resistance alleles that confer high levels of resistance have been recently identified in the voltage-sensitive sodium channel, and their frequencies in field populations are unknown. Our aim in this study was to reassess the resistance status of house flies from select locations in the United States by examining resistance levels against commonly used insecticides and frequencies of known resistance alleles. House flies were collected from animal production facilities in five different states between 2016 and 2018. Resistance levels to three insecticides (permethrin, tetrachlorvinphos, and methomyl), representing three classes of insecticides (pyrethroids, organophosphates and carbamates) varied geographically and were lowest in the population collected from New Mexico, intermediate in the population collected from Utah, and greatest in the population from Kansas. The recently identified 1B pyrethroid resistance allele increased dramatically in frequency compared to previous reports, most notably in populations from Kansas and Maryland, indicating that it may already be widespread around the United States. Based on comparison with historical data, the population collected from Kansas represents one of the most highly permethrin resistant populations ever sampled. If the alleles responsible for this level of resistance spread, pyrethroids may be of limited use for house fly control in the United States in the near future.
家蝇种群对杀虫剂的抗药性是全球畜牧业生产者面临的主要问题。2008-2009 年对美国的杀虫剂抗性水平和拟除虫菊酯抗性等位基因频率进行了调查，但对于过去 10 年抗性水平的变化知之甚少。此外，最近在电压敏感钠通道中发现了新的、能赋予高水平抗性的靶标位点拟除虫菊酯抗性等位基因，但其在田间种群中的频率尚不清楚。本研究的目的是通过检查对常用杀虫剂的抗性水平和已知抗性等位基因的频率，重新评估美国选定地点家蝇的抗性状况。2016 年至 2018 年间，从五个不同州的动物生产设施中采集了家蝇。对三种杀虫剂（氯菊酯、四氯虫酰胺和灭多威）的抗性水平（代表三种杀虫剂类别：拟除虫菊酯类、有机磷类和氨基甲酸酯类）存在地理差异，在新墨西哥州采集的种群中最低，在犹他州采集的种群中居中，在堪萨斯州采集的种群中最高。最近发现的 1B 型拟除虫菊酯抗性等位基因的频率与以往报告相比显著增加，尤其是在堪萨斯州和马里兰州的种群中，表明它可能已经在美国各地广泛传播。与历史数据相比，堪萨斯州采集的种群代表了迄今为止采样的最具氯菊酯抗性的种群之一。如果导致这种抗性水平的等位基因传播，拟除虫菊酯类药剂在不久的将来可能对美国的家蝇控制作用有限。
