Evaluation of efficacy of formic acid and thermal remediation for management of Tropilaelaps and Varroa mites in central Thailand

The western honey bee, Apis mellifera, faces a new threat from the spread of parasitic Tropilaelaps (Tropi) mites, specifically T. mercedesae, which adds additional complexity to an apicultural landscape heavily impacted by Varroa destructor. In this study conducted in central Thailand, we investigated the efficacy of two methods of applying formic acid and a thermal remediation technique in controlling Tropi mites and Varroa, focusing our attention on the reproductive stage of the mites which is restricted to capped brood cells. Results revealed that both formic acid treatments (Formic Pro and liquid formic acid) demonstrated an immediate and substantial reduction in live Tropi and Varroa populations, maintaining near-zero levels for the 3- week duration of the study. In contrast, thermal remediation, employing heating pads, exhibited a more gradual decline, achieving an 85.42% reduction in Tropi mites and a 92.33% reduction in Varroa mites by week three. Notably, heat-treated colonies experienced an unexpected resurgence in mite populations during week two. The findings contribute valuable insights into potential strategies for mitigating the threat of Tropi mites and highlight the urgency of further research to safeguard global honey bee populations.