Comparison of Two Diagnostic Techniques for the Apis mellifera Varroatosis: Strengths, Weaknesses and Impact on the Honeybee Health

SIMPLE SUMMARY: Varroa destructor is the main parasite affecting the health of adult honey bees and their larval forms. This mite negatively influences beekeeping income, as it can cause a decrease in yields and the loss of entire colonies of an apiary. To control this parasite, it is essential to establish the level of infestation through a precise diagnosis. In this work, two techniques used for the diagnosis of V. destructor on a bee sample were compared: the sugar roll test and CO(2) injection. Both techniques were evaluated with the Varroa EasyCheck tool. This device is particularly versatile because it allows you to choose between different diagnostic techniques. The results of a comparison show that the sugar roll technique is cheaper and results in greater diagnostic accuracy. Both methods do not have a major impact on the health and welfare of bees compared to the alcohol washing method, which results in the death of the test sample. This study is of particular practical value, as it guides beekeepers in choosing the technique to use in a crucial practice for breeding, which is diagnosis. ABSTRACT: Varroa destructor is the most dangerous pest that poses a threat to honey bee survival. In recent years, increasingly worrying phenomena of drug resistance have occurred to various active ingredients of pharmaceutical formulations used to control this parasitosis. Determining the level of infestation is essential to preventing the inappropriate use and abuse of veterinary medicines, and to choose the most appropriate time for treatment. This comparative study investigates the sensitivity and diagnostic accuracy of two field techniques for diagnosing V. destructor infestations in hives. The EasyCheck device (Véto-pharma) was used in two of its application modes, namely, the sugar roll test and carbon dioxide (CO(2)) injection. The experiments were conducted on 15 samples of 300 bees each taken from the same frame and checked for the presence of mites using standard and modified field techniques in both uncaged and caged queen hive conditions. The results demonstrate that the sugar roll technique is significantly more effective and safer than CO(2) injection, allowing for a higher accuracy in diagnosing a V. destructor infestation. Furthermore, the evaluation of mites present on bees in brood block conditions has proven to be particularly reliable. Considering the number of mites on the filter of the device as an additional step helps to implement the diagnostic accuracy of the CO(2) injection technique, however, not achieving the efficacy results of the sugar roll.