Afful E, Elliott Brent, Nayak Manoj K, Phillips Thomas W
Department of Entomology, Kansas State University, Manhattan, KS.
Infestation Control and Sanitation, Canadian Grain Commission, Winnipeg, Manitoba, Canada.
J Econ Entomol. 2018 Feb 9;111(1):463-469. doi: 10.1093/jee/tox284.
Phosphine is the most widely used fumigant for stored grain insect pests, and resistance to phosphine has evolved in several species worldwide. This study was designed to determine the presence of phosphine resistance in 34 populations of Rhyzopertha dominica (F.) collected from the United States and Canada. Adult R. dominica were sampled and subjected to a discriminatory dose toxicity assay of exposure to 20 ppm of phosphine for 20 h of exposure to distinguish a susceptible R. dominica adult by death from a resistant beetle that survives the treatment. All but two of the 34 geographic populations surveyed had some beetles that were resistant to phosphine, and the frequency of resistance varied from 97% in a population from Parlier, California to 0% in beetles from both Carnduff, Saskatchewan and Starbuck, Manitoba. Probit analyses of dose-mortality bioassays with beetles from a laboratory-susceptible strain and those from five of the populations sampled were used to calculate resistance ratio factors (RRs) based on the ratio of LC50 (estimate for the concentration to kill 50% of a test group) in the sampled population to the LC50 for the susceptible strain. The highest RR for the five resistant populations was nearly 596-fold in beetles from Belle Glade, Florida, whereas the lowest RR in that group was 9-fold in Wamego, Kansas. This study revealed that phosphine resistance in R. dominica is common across North America and some populations have levels of resistance that may pose challenges for continued use of phosphine for their management.
磷化氢是用于防治储粮害虫的最广泛使用的熏蒸剂，全球已有多个物种对磷化氢产生了抗性。本研究旨在确定从美国和加拿大采集的34个谷蠹种群中是否存在对磷化氢的抗性。对谷蠹成虫进行采样，并使其接受20 ppm磷化氢、暴露20小时的鉴别剂量毒性试验，以通过死亡区分敏感的谷蠹成虫和经处理后存活的抗性甲虫。在调查的34个地理种群中，除两个种群外，其他种群均有一些甲虫对磷化氢具有抗性，抗性频率从加利福尼亚州帕利耶尔种群的97%到萨斯喀彻温省卡恩达夫和马尼托巴省斯塔巴克的甲虫的0%不等。对来自实验室敏感品系的甲虫以及所采样的五个种群的甲虫进行剂量-死亡率生物测定的概率分析，以基于采样种群中LC50（杀死测试组50%个体的估计浓度）与敏感品系LC50的比值计算抗性比率因子（RRs）。五个抗性种群中，佛罗里达州贝勒格莱德的甲虫的最高RR接近596倍，而该组中堪萨斯州韦莫戈的最低RR为9倍。本研究表明，谷蠹对磷化氢的抗性在北美很普遍，一些种群的抗性水平可能会给继续使用磷化氢进行防治带来挑战。
