Scientists Tested America’s Dying Honeybees — And Every Mite Had the Same Mutation

When USDA scientists began sampling collapsing honeybee colonies across California and the West in January 2025, they expected the usual suspects — instead, every one of the 39 Varroa mites they genotyped carried the same mutation, Y215H, the change that makes amitraz, the industry's last reliable mite treatment, useless. Just two years earlier the same mutation had been found in 66% of American mites. Now it was 100%, in colonies whose beekeepers had followed the label and hung the strips anyway. Even more startling, whole-colony tests showed nothing — weak hives and strong hives carried the same viral loads. The virus signal only appeared when researchers picked up individual dying bees, where deformed wing virus B turned up in 100% of cases, and a single bee's viral load, diluted to one part in ten million, killed every healthy bee it was injected into. The discovery means America's commercial beekeeping system — 2.8 million colonies, trucked every February to pollinate a $20 billion crop — has been running a twenty-year selection experiment on its own parasite, and the experiment is finished. The worst year on record cost 1.6 million colonies and about $600 million. This is the story of how a few dozen mites exposed the collapse of a chemical the entire industry depended on, and why the lab that found it may not survive the finding.