Assessment of the levels of resistance of Tropilaelaps mercedesae to a variety of synthetic miticide.

The introduction of the western honey bee Apis mellifera to Asia has seen the parasitic mites Varroa destructor and Tropilaelaps spp. transfer from their native Asian honey bee hosts (Apis cerana and Apis dorsata respectively) to infest the brood of A. mellifera causing significant damage to colonies and colony losses. T. mercedesae was recently detected in Europe for the first time in A. mellifera colonies and is considered a more damaging parasite of A. mellifera than Varroa. Beekeepers rely heavily on the use of synthetic miticides and organic chemicals to control Varroa and Tropilaelaps which has resulted in Varroa developing resistance to many synthetic miticides and these treatments becoming less effective. Less is known about chemical resistance in Tropilaelaps as no study has been undertaken that specifically looks at this issue, but there is evidence to suggest that Tropilaelaps do have resistance to chemicals such as Amitraz, Coumaphos, Flumethrin and Fluvalinate. The use of synthetic miticides is widely recommended for surveillance and detection of Tropilaelaps and this recommendation forms a part of the contingency response of several government agencies. The study developed a novel chemical resistance test for Tropilaelaps and sought to test the efficacy of commercially available synthetic miticides and found that mites were resistant to all the synthetic chemical treatments tested apart from Amitraz which was shown to be 64% effective. Understanding and managing miticide resistance in this species is critical to prevent its further spread and colony losses.