Instituto de Ecología y Evolución, Universidad Austral de Chile, Casilla 567, Valdivia, Chile.
J Econ Entomol. 2011 Feb;104(1):258-65. doi: 10.1603/ec10188.
The horn fly, Haematobia irritans (L.) (Diptera: Muscidae), was introduced to Chile in the beginning of the 1990s. Since its introduction, farmers have controlled this pest almost exclusively with insecticides. To understand the consequences of different control strategies on the development of insecticide resistance and their persistence, a field survey was conducted at eight farms in the south of Chile to characterize insecticide resistance in field populations and resistance mechanisms. Horn fly samples were assayed to determine levels of resistance to pyrethroids and diazinon, genotyped for kdr and HialphaE7 mutations, and tested for general esterase activity. All field populations, including ones that were not treated with insecticides for the past 5 yr, showed high levels of cypermethrin resistance and high frequencies of the kdr mutation. None of the fly populations demonstrated resistance to diazinon and the HialphaE7 mutation was not detected in any of the fly samples. Esterase activities in all populations were comparable to those found in the susceptible reference strain. The findings of high frequencies of homozygous resistant and heterozygous individuals both in insecticide treated horn fly populations and in the untreated fly populations suggests complex interactions among field populations of the horn fly in Chile.
角蝇，Haematobia irritans（L.）（双翅目：蝇科），于 20 世纪 90 年代初被引入智利。自引入以来，农民几乎完全依靠杀虫剂来控制这种害虫。为了了解不同控制策略对杀虫剂抗性发展及其持久性的影响，在智利南部的八个农场进行了田间调查，以确定田间种群的杀虫剂抗性特征和抗性机制。对角蝇样本进行了抗药性测试，以确定对拟除虫菊酯和二嗪农的抗性水平、基因型为 kdr 和 HialphaE7 突变，并测试了普通酯酶活性。所有田间种群，包括过去 5 年未用杀虫剂处理的种群，均表现出高水平的氯氰菊酯抗性和 kdr 突变的高频率。没有一个蝇种群对二嗪农表现出抗性，也没有在任何蝇样本中检测到 HialphaE7 突变。所有种群的酯酶活性与敏感参考株相似。在经杀虫剂处理的角蝇种群和未经处理的角蝇种群中，均发现高比例的纯合抗性和杂合抗性个体，这表明智利角蝇田间种群之间存在复杂的相互作用。
