Table_2_Seasonal differences in Varroa destructor population growth in western honey bee (Apis mellifera) colonies.pdf

Varroa destructor is a major threat for apiculture worldwide. A successful approach to control this parasite must include the application of effective treatments at the correct time. To understand the effect that treatment timing has on Varroa populations at different seasons, we conducted an experiment using a dataset comprising two separate field trials over multiple years, both trials containing four apiary sites composed of 20 honey bee colonies across an area representative of north central Florida environments. Before the start of the season, colonies were treated with two acaricides simultaneously to bring the Varroa populations to ∼0.25 mites/100 bees. Following treatment, we monitored the mite populations monthly via alcohol washes. Our results show that the temporal efficacy of Varroa treatments varies across seasons. We observed that it takes about 4–5 months after treatment in winter and spring for mite populations to return to the standard economical threshold (3 mites/100 bees). Nevertheless, there is a steeper increase in mite populations (<3 months to exceed the economic threshold) after treating colonies in summer and fall. The level of infestation that leads to colony collapse and the rate of colony decline also varied by season. To our knowledge, this is the first study evaluating seasonal effects on Varroa population growth and the first model of Varroa population growth in Florida, USA. Our results serve as a foundation for Varroa treatment models, aiding beekeepers in the future as a part of a holistic approach to control this devastating honey bee parasite.

瓦螨（Varroa destructor）是全球养蜂业面临的主要威胁。对该寄生虫的有效防控，必须在恰当时机施用针对性防治手段。为明确施药时机对不同季节瓦螨种群的影响，我们开展了一项实验，其所用数据集包含两项独立的多年田间试验：两项试验均设置4个养蜂场点位，每个点位包含20群蜜蜂蜂群，试验区域的环境特征与佛罗里达州中北部地区相符。试验季开始前，研究人员同时施用两种杀螨剂，将瓦螨种群密度降至约0.25只/100只蜜蜂。施药后，我们每月通过酒精冲洗法监测螨类种群数量。我们的研究结果表明，瓦螨防治措施的时效防控效果随季节发生显著变化。观察显示，冬、春两季施药后，螨类种群需约4-5个月才能回升至经济阈值标准（3只/100只蜜蜂）。不过，夏、秋两季施药后，螨类种群增长速度更快，仅需不足3个月即可突破经济阈值。引发蜂群崩溃的螨类侵染水平以及蜂群衰退速率，同样存在季节差异。据我们所知，本研究是首个评估季节因素对瓦螨种群增长影响的实验，同时也是美国佛罗里达州首个瓦螨种群增长模型。本研究结果可为瓦螨防治模型提供理论基础，助力养蜂从业者后续开展综合防控工作，以应对这种极具破坏性的蜜蜂寄生虫。