Amitraz-resistant varroa mites leave beekeepers with no reliable fall treatment

Commercial and sideliner beekeepers who relied on amitraz-based miticides (Apivar strips) as their primary fall varroa treatment are discovering the treatment no longer works. Varroa destructor mites in their colonies have developed widespread resistance to amitraz, the most-used synthetic miticide in US beekeeping. The 2024-2025 season saw 55.6% colony losses nationally -- the worst since surveys began in 2010 -- and USDA sampling found amitraz resistance in virtually all varroa collected from collapsed colonies. The problem cascades: without effective fall knockdown, mite-vectored viruses (deformed wing virus, acute bee paralysis virus) explode through the colony over winter, killing it by February. Beekeepers must then spend $200-250 per replacement package to rebuild in spring, often too late for almond pollination contracts. The reason this persists structurally is that amitraz was the only synthetic miticide that could be applied during honey supers and worked reliably for 20+ years, so beekeepers never built rotation protocols into their standard practice. Alternative treatments like oxalic acid and formic acid are temperature-sensitive, harder to apply at scale, and less effective when brood is present -- meaning there is no drop-in replacement for what amitraz used to do.