Episode Details

In this Bee Science Short, Dr. Dewey Caron continues his series on integrated pest management (IPM) for Varroa mites, focusing on the critical step of selecting and applying the right tools at the right time.

Dewey emphasizes a simple but essential message: have a plan. Effective Varroa control begins with understanding pest levels, assessing risk, and determining when intervention is necessary based on economic injury levels (EIL). From there, beekeepers must choose appropriate management tools to keep mite populations below damaging thresholds.

The episode highlights the importance of early-season intervention. By reducing mite populations in late winter and early spring—particularly through oxalic acid treatments—beekeepers can lower the initial "inoculum" of mites and slow population growth throughout the season. This proactive approach helps flatten the mite population curve and reduces the likelihood of damaging fall peaks.

Dewey reviews a range of control options, including mechanical methods such as drone brood removal and brood interruption, as well as chemical treatments. These include amitraz-based products, organic acids like formic and oxalic acid, and essential oil treatments. He also discusses emerging research on resistance, including amitraz resistance mechanisms and ongoing work to improve treatment effectiveness.

Importantly, the episode underscores that Varroa damage is driven not just by mite numbers, but by their role in spreading viruses such as Deformed Wing Virus (DWV). This reinforces the need for consistent, integrated management throughout the season.

This episode provides a science-based framework for building a Varroa management plan that supports healthier colonies and more successful beekeeping outcomes.

Links and references mentioned in this episode:

• Caron Dewey and committee. 2026. Tools for Varroa Management, 9th edition. Honey Bee Health Coalition.
• Matías D., Maggi, et. al. (incl Diana Sammataro.) 2017. The susceptibility of Varroa destructor against oxalic acid: a study case. Bull. Insectology 70 (1): 39-44, ISSN 1721-8861
• Jernej Bubnič et.al 2024. Integrated Pest Management Strategies to Control Varroa Mites and Their Effect on Viral Loads in Honey Bee Colonies. Insects 5;15(2):115. doi: 10.3390/insects15020115
• Rinkevich, F. D., Moreno-Martí, S., Hernández‐Rodríguez, C. S. & González‐Cabrera, J.2023. Confirmation of the Y215H mutation in the β2 ‐octopamine receptor in Varroa destructor is associated with contemporary cases of amitraz resistance in the United States. Pest Manag. Sci. 79, https://scijournals.onlinelibrary.wiley.com/doi/abs/10.1002/ps.7461
• Rogan Tokach, Frank Rinkevich, et.a.. March 18, 2026. Evaluation of late-season Varroa destructor treatments and their impact on amitraz resistant mite populations. Scientific Reports., https://www.nature.com/articles/s41598-026-44796-8
• Bozkus, Mustafa, Carolyn Breece, Hannah Lucas, Nathalie A Steinhauer, and Ramesh R Sagili. 2025. Oxalic acid vaporization: effectiveness against Varroa destructor (Mesostigmata: Varroidae) and safety for Apis mellifera(Hymenoptera: Apidae). J.Ins. Sci. Vol 25, Issue 6, ieaf091,

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