Earlier this year, commercial beekeepers across the U.S. faced unprecedented winter colony losses, with some reporting over 60% of hives perishing — more than double the typical overwintering loss rates.
Hobbyists and sideliners — those who keep bees as a secondary source of income — also saw catastrophic declines, with total economic impacts to beekeepers estimated at over $600 million.
Now, scientists are linking the losses to high viral loads and mite resistance as they work to develop solutions to protect the industry moving forward.
“This is the worst overwintering loss we’ve seen in years,” said Lewis Bartlett, University of Georgia assistant professor with a joint appointment in the Department of Entomology at the College of Agricultural and Environmental Sciences and the Odum School of Ecology. “We started getting signals back in January, and now major organizations like the Honey Bee Health Coalition, USDA-ARS and Project Apis m. are mobilizing funding and resources to respond.”
Weather, queens and disease under scrutiny
Experts point to a range of contributing culprits behind the collapse: erratic weather patterns tied to a La Nina year that disrupted plant flowering times and bee flight schedules; a potential bottleneck in the supply of high-quality honey bee queens, which are mostly produced in Georgia, California, Texas and Hawaii; and spikes in existing or emerging bee diseases.
New research findings from the U.S. Department of Agriculture’s Agricultural Research Service (USDA-ARS) have revealed that high levels of viral infections, vectored by Varroa destructor (Varroa) mites, are the key driver of the collapse.
“Our honey bees have been struggling for decades as the Varroa mite acts like a ‘bee tick’, injuring the bees by feeding on them, but more importantly, spreading diseases — including damaging viruses,” Bartlett said. “Beekeepers have fewer and fewer options to control Varroa mites as the parasite has evolved to become resistant to most of the chemicals we once used.”
Varroa mites spread through the U.S. in the 1980s and 90s, except for Hawaii, which saw the pest arrive much later.
The 2024-25 losses were a regional case of overwinter and springtime loss of honey bee colonies, but the loss was extreme in locations where it was witnessed, according to Bartlett.
“From what we now know, disasters like this could pop up in different places year to year, based on whether beekeepers in that location are (over) reliant on Amitraz — a pesticide primarily used to kill mites— for Varroa control, whether there was a difficult spring or summer in the previous year limiting nutrition, and whether there were other crop pest outbreaks in that region that meant pesticide use on-farms were unusually high,” he said. “That combination creates a perfect storm for viral epidemics in bees, which seems to be the case here.”
New research aims to combat honey bee disease and strengthen colony resilience
Bartlett, a key researcher in nationwide honey bee health and current program lead of the UGA Bee Program, is part of a major research collaboration working on solutions, including efforts to control Varroa mites — a persistent and deadly threat to bee populations.
“It is impossible to prevent disease spread with dwindling genetic diversity, well-populated hives and bee movement in apiaries and between farms,” Bartlett said. “By deepening our understanding of these challenges, we’re hopeful that ongoing research will lead to improvements in honey bee breeding, new products and better management strategies, and agricultural policy recommendations that can be widely used to support healthier colonies.”
The Honey Bee Health Coalition will release an updated version of its “Tools for Varroa Management” guide later this year. The guide is a key resource for beekeepers, providing science-based strategies for monitoring and controlling Varroa populations.
Learn more about UGA honey bee research and visit resources for beekeepers at bees.caes.uga.edu.
