Mullens Bradley A, Watson D Wes, Gerry Alec C, Sandelin Broc A, Soto Diane, Rawls Diana, Denning Steve, Guisewite Lena, Cammack Jonathan
Department of Entomology, University of California, Riverside, CA 92521, USA.
Department of Entomology, North Carolina State University, Raleigh, NC 27695, USA.
Vet Parasitol. 2017 Oct 15;245:14-28. doi: 10.1016/j.vetpar.2017.08.005. Epub 2017 Aug 12.
Adult horn fly populations were tracked on cattle for 2-week periods before, during and after multiple treatments (every 3-4days) with two repellents in a mineral oil carrier. Cattle were sprayed four times in a two-week period either with 2% geraniol (125ml/cow) or a 15% mixture of short chain fatty acids (C8-C9-C10)(250ml/cow), and there were untreated control cattle. Trials were conducted in California and North Carolina for 3 summers. Short-term fly counts (same day) on treated cattle were reduced by 61-99%, depending on material and trial, and the fatty acid mixture provided better control than geraniol. Horn fly counts were suppressed for 1-3 d and rebounded somewhat after both treatments. Consecutive treatments showed evidence of persistent impact in California where herds were more isolated. Rebounds to pre-treatment levels 3-4 d after treatment occurred more often in North Carolina, where other infested cattle were closer to treated herds. By 3-4 d post-treatment, horn flies were reduced by 29-61% in California and 0-83% in North Carolina, relative to pre-treatment. Background behavior frequencies were assessed from hundreds of counts on untreated, infested California cattle, where horn flies were the only abundant biting fly. Behavior averages were 16.5 tail flicks, 7.6 skin twitches, 1.2 head throws, or 0.2 leg stamps per 2min observation period. At horn fly densities from about 200 to more than 1000 flies per animal (moderate to high numbers), fly defensive behaviors on control cattle were poorly related (or unrelated) to fly numbers. Immediately after repellent application, however, flies were almost absent and behavior frequencies dropped distinctly. Cattle fly defensive behaviors therefore seem to be quite sensitive to low (less than 100 flies/animal) horn fly densities, and behaviors would be a poor quantitative tool to track fly stress at moderate densities and above. Both geraniol and the fatty acids show promise for horn fly control, especially in organic agriculture. Treatments at 1-2 d intervals probably would keep infestations below the economic threshold (200 flies/cow).
在使用两种以矿物油为载体的驱虫剂对成年角蝇种群进行多次处理（每3 - 4天一次）之前、期间和之后，对牛群中的角蝇进行了为期2周的跟踪。在两周内，牛群被喷洒了4次，分别是2%香叶醇（125毫升/头）或15%短链脂肪酸（C8 - C9 - C10）混合物（250毫升/头），同时设有未处理的对照牛群。试验在加利福尼亚州和北卡罗来纳州进行了3个夏天。根据材料和试验的不同，处理后牛群当天的短期蝇数减少了61% - 99%，且脂肪酸混合物的防治效果优于香叶醇。两种处理对角蝇数量的抑制作用持续1 - 3天，之后数量会有所反弹。在加利福尼亚州，连续处理显示出持续影响的迹象，那里的牛群更为隔离。在北卡罗来纳州，处理后3 - 4天数量反弹至处理前水平的情况更为常见，因为那里其他受感染的牛群距离处理过的牛群更近。相对于处理前，处理后3 - 4天，加利福尼亚州的角蝇数量减少了29% - 61%，北卡罗来纳州减少了0 - 83%。通过对未处理的、受角蝇侵扰的加利福尼亚牛群进行数百次计数，评估了背景行为频率，在这些牛群中角蝇是唯一数量众多的叮咬蝇。行为平均值为每2分钟观察期内16.5次甩尾、7.6次皮肤抽搐、1.2次甩头或0.2次跺脚。在每头牛有大约200至超过1000只角蝇（中等至高数量）的密度下，对照牛群的防蝇行为与蝇数量的相关性较差（或无相关性）。然而，在施用驱虫剂后，角蝇几乎消失，行为频率明显下降。因此，牛的防蝇行为似乎对低密度（每头牛少于100只角蝇）的角蝇密度非常敏感，而在中等密度及以上时，这些行为作为跟踪蝇类应激的定量工具效果不佳。香叶醇和脂肪酸在控制角蝇方面都有前景，尤其是在有机农业中。每隔1 - 2天进行处理可能会使侵扰保持在经济阈值（每头牛200只蝇）以下。
