Development and Evaluation of a New Effective Tool and Method for Assessing Varroa destructor (Acari: Varroidae) Mite Populations in Honey Bee Colonies

SIMPLE SUMMARY: To avoid losses of honey bee colonies, beekeepers should monitor the populations of the harmful ectoparasitic mite, Varroa destructor (Anderson–Truman). Here, we describe a novel device and method for monitoring mite populations. The Varroa Shaker Device (VSD) is constructed of sections of polyvinyl chloride (PVC) pipe that utilizes screens of two mesh sizes that separate the bees from the mites and captures the mites for easy counting. The VSD can be used by shaking bees with only water as the wash solution but may also be used with alcohol wash solutions; the VSD accurately assessed mite loads using fewer than 250 bees and shaken with 250 mL of water for one minute. The recovery of mites using the VSD is >90%, which is such as that recorded for using the commonly used sugar roll method but is easier to use in both laboratory and field settings. Additionally, tests demonstrated that for the VSD to assure accurate mite counts are achieved, honey bees should be taken from frames with an open and/or capped brood where the mites are more likely located. ABSTRACT: A new device for assessing Varroa destructor (Anderson–Truman) mite infestations in honey bee colonies was designed, tested, and evaluated against the sugar roll method, a widely used method by beekeepers. The Varroa Shaker Device (VSD) is constructed of polyvinyl chloride (PVC) pipe that separates into three parts. Inside the shaker there are two mesh sizes; the larger mesh separates the bees from the mites, and the smaller mesh captures the mites. The VSD can be used by shaking bees with only water as the wash solution. The recovery of mites using the VSD is >90%, which is such as that recorded for using the sugar roll method. Our tests demonstrated that the VSD accurately assessed mite loads when fewer than 250 bees were sampled and shaken with 250 mL of water for one minute. To assure accurate mite counts are achieved with any sampling device, honey bees should be taken from frames with an open and/or capped brood where the mites are more likely located. The VSD can be used in both laboratory and field settings to accurately assess honey bee colonies for levels of mite infestation or for collecting live mites for research purposes.