Oxalic acid (OA) is a natural compound that has been used to control the honey bee (Apis mellifera) pest Varroa destructor. One method of OA application gaining popularity among beekeepers in the US involves vaporizing OA crystals with heat inside a closed hive. Herein, we tested different doses of OA applied via vaporization to determine the most effective amount of OA needed to reduce V. destructor populations below that of the negative controls. Forty experimental colonies were assigned to one of four treatment groups, with ten colonies composing each group. The four treatments were: (1) 1 g OA, (2) 2 g OA, (3) 4 g OA and (4) no OA (negative control). The OA was applied via vaporization once per week for three weeks. V. destructor infestation rate and colony strength assessments were estimated before, during, and after treatment applications. Colonies in the 4 g OA treatment group had significantly lower infestation rates than did those in the untreated control and 1 g OA treatment groups, but not those in the 2 g OA treatment group. The infestation rate of colonies treated three times with 1 g OA, which is the current legal limit for OA vaporization in the US, was not significantly different from that of colonies in the negative control or 2 g OA treatment groups. Colonies receiving the highest dose of OA were generally healthier than those treated at lower OA doses. Our results may lead to improved efficacy of OA vaporization, thus aiding beekeepers in their efforts to control V. destructor.

草酸（OA）是一种天然化合物，已被用于控制蜜蜂（Apis mellifera）害虫Varroa破坏物。OA应用在美国养蜂人中越来越受欢迎的一种方法是在封闭的蜂巢内加热使OA晶体汽化。在本文中，我们测试了通过汽化施加的不同剂量的OA，以确定将V. destructor种群减少到阴性对照以下所需的最有效OA量。40个实验菌落被分配到四个治疗组之一，每组十个菌落。四种处理方法是：（1）1 g OA，（2）2 g OA，（3）4 g OA和（4）无OA（阴性对照）。每周一次通过蒸发应用OA，持续三周。五，析构函数在治疗前，治疗中和治疗后评估感染率和菌落强度评估。4 g OA处理组的菌落侵染率明显低于未处理的对照组和1 g OA处理组，但2 g OA处理组则没有。用1 g OA处理过3次的菌落侵染率是美国目前对OA气化的法定极限，与阴性对照组或2 g OA治疗组的菌落侵染率没有显着差异。接受最高OA剂量的菌落通常比使用较低OA剂量的菌落更健康。我们的结果可能会提高OA蒸发的功效，从而帮助养蜂人努力控制灭弧菌。