Underwood Robyn M, Currie Robert W
Department of Entomology, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2.
J Econ Entomol. 2005 Dec;98(6):1802-9. doi: 10.1093/jee/98.6.1802.
The combination of the concentration of formic acid and the duration of fumigation (CT product) during indoor treatments of honey bee, Apis mellifera L., colonies to control the varroa mite, Varroa destructor Anderson & Trueman, determines the efficacy of the treatment. Because high concentrations can cause queen mortality, we hypothesized that a high CT product given as a low concentration over a long exposure time rather than as a high concentration over a short exposure time would allow effective control of varroa mites without the detrimental effects on queens. The objective of this study was to assess different combinations of formic acid concentration and exposure time with similar CT products in controlling varroa mites while minimizing the effect on worker and queen honey bees. Treated colonies were exposed to a low, medium, or high concentration of formic acid until a mean CT product of 471 ppm*d in room air was realized. The treatments consisted of a long-term low concentration of 19 ppm for 27 d, a medium-term medium concentration of 42 ppm for 10 d, a short-term high concentration of 53 ppm for 9 d, and an untreated control. Both short-term high-concentration and medium-term medium-concentration fumigation with formic acid killed varroa mites, with averages of 93 and 83% mortality, respectively, but both treatments also were associated with an increase in mortality of worker bees, queen bees, or both. Long-term low-concentration fumigation had lower efficacy (60% varroa mite mortality), but it did not increase worker or queen bee mortality. This trend differed slightly in colonies from two different beekeepers. Varroa mite mean abundance was significantly decreased in all three acid treatments relative to the control. Daily worker mortality was significantly increased by the short-term high concentration treatment, which was reflected by a decrease in the size of the worker population, but not an increase in colony mortality. Queen mortality was significantly greater under the medium-term medium concentration and the short-term high concentration treatments than in controls.
在室内对意大利蜜蜂（Apis mellifera L.）蜂群进行甲酸熏蒸处理以控制狄斯瓦螨（Varroa destructor Anderson & Trueman）时，甲酸浓度与熏蒸持续时间的乘积（CT值）决定了处理效果。由于高浓度会导致蜂王死亡，我们推测，长时间低浓度给予高CT值比短时间高浓度给予更能有效控制狄斯瓦螨，同时对蜂王无不利影响。本研究的目的是评估具有相似CT值的甲酸浓度和暴露时间的不同组合在控制狄斯瓦螨的同时，尽量减少对工蜂和蜂王的影响。处理过的蜂群暴露于低、中或高浓度的甲酸中，直至室内空气中的平均CT值达到471 ppm·d。处理包括长期低浓度19 ppm熏蒸27天、中期中等浓度42 ppm熏蒸10天、短期高浓度53 ppm熏蒸9天，以及一个未处理的对照。短期高浓度和中期中等浓度的甲酸熏蒸均能杀死狄斯瓦螨，平均死亡率分别为93%和83%，但这两种处理也都导致工蜂或蜂王或两者的死亡率增加。长期低浓度熏蒸效果较低（狄斯瓦螨死亡率为60%），但未增加工蜂或蜂王的死亡率。来自两位不同养蜂人的蜂群中，这种趋势略有不同。相对于对照，所有三种甲酸处理中狄斯瓦螨的平均数量均显著减少。短期高浓度处理显著增加了每日工蜂死亡率，这反映在工蜂数量的减少上，但并未增加蜂群死亡率。中期中等浓度和短期高浓度处理下的蜂王死亡率显著高于对照。
