Virus spreading mite blamed for 60% loss of bee colonies needed to pollinate food crops

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2 days ago

A catastrophic loss of bee colonies over the winter has been blamed on a mite that injects a virus into the bees and spreads the deadly pathogen throughout their colonies.
Between 60% to 70% of the bees used to pollinate crops, including almonds in California, apples in New York and blueberries and watermelons in Central Florida have been lost, according to Robbie Bell, a beekeeper who runs an apiary at the Honey Bell Bee Co. in Fort Meade.
'We kind of figured it was a virus,' he said of a recent USDA confirmation of the cause. 'This year was a bad year' compared to the usual 30% to 40% casualty rate among the pollinators.
The U.S. Agricultural Department issued a news release on June 3 saying its research has linked 'early 2025 honeybee losses to high viral loads and mite resistance.'
'The findings point to alarmingly high levels of viral infections — vectored by Varroa destructor (Varroa) mites with resistant genes to a common treatment — as key drivers of colony collapse,' the USDA said.
It turns out the trips across the United States for bees to pollenate the crops can be very hazardous for bees. They encounter agricultural fungicides, pesticides and often drink water from farm ponds laden with runoff from the application of such chemicals.
'That's another layer to the puzzle,' said Bell of several potential factors weakening the pollinators.
The USDA echoed such factors in its release. Factors such as pesticide exposure, poor nutrition and environmental conditions may have exacerbated the losses, the USDA said.
Bell estimates that about 80% of agricultural crops in the United States are pollenated by bees, as butterflies, bumblebees and other pollinator insects that once occurred naturally have declined in population in the past 10 to 20 years.
Regarding almonds, Bell said 100% of the crop is pollinated by bees. The demand for bees to pollinate has Bell's bees booked up years in advance.
But smaller beekeepers may have fared much better, according to Jan Betters at Pat's Apiaries, which has some hives in the Wahneta and other areas of Polk County. The Auburndale-based operation takes about 100 hives to an Alturas blueberry farm every year and sells honey locally at farmers markets.
'We are very careful to take out bees to farms that only spray when bees are in the hives,' she said. The practice keeps their bees away from potential environmental hazards but in large scale agricultural setting in miles long groves, such practices are more difficult to coordinate.
Their die off rate is about 10% to 20% per year, a loss much less than the rates at commercial beekeepers.
According to the USDA, after reports from beekeepers about the die off, a study analyzed samples from six major commercial beekeeping operations affected by the losses. The samples provided 'the most detailed evidence to date of the biological factors behind the widespread die-offs.'
'Collectively, these operations managed nearly 184,000 colonies — roughly 7% of all U.S. hives — and reported losses averaging over 60%, just as bees were being staged for California's almond pollination season," the USDA said.
'The beekeeping and bee health community appreciates the work of the USDA-ARS bee research laboratories. They quickly took samples of lost colonies and now that they've released the analysis, beekeepers can better understand what happened and take action,' said Matt Mulica, senior project director at Keystone Policy Center, which facilitates the Honey Bee Health Coalition.
'We understand more analysis is occurring and we look forward to learning more about the other potential causes of these significant colony losses,' he said in the release.
Researchers found high levels of Deformed Wing Virus (DWV-A and DWV-B) and Acute Bee Paralysis Virus in both pooled colony samples and individual bees showing shaking and other signs of morbidity, the USDA said. Experimental inoculation further confirmed these viruses as the likely cause of mortality in collapsing colonies.
Crucially, all Varroa mites collected from affected colonies tested positive for a genetic marker linked to resistance to amitraz, the most commonly used miticide in commercial beekeeping, the USDA said. This finding underscores the need for new tools and pest management strategies.
'This is a critical moment for honey bee health,' said Patty Sundberg, president of the American Beekeeping Federation. 'We can't continue relying on a single line of defense against Varroa. These mites are evolving quickly, and our management tools must evolve just as fast. We also need to find treatments for these viruses and we await the release of how pesticide exposure and poor nutrition amplify the impacts from these viruses.'
Steven Coy, president of the American Honey Producers Association, added, 'The findings released today are a crucial first step in providing beekeepers actionable information. It highlights the necessity for additional miticides and methods of controlling varroa and the associated viruses.
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We urge the USDA to provide the results of the impacts of nutritional, chemical and environmental stress as soon as possible. Beekeepers need a complete picture of what happened in order to make sound decisions regarding the health of our colonies.'
In 2021, the Honey Bee Health Coalition published "Guide to Varroa Mite Controls for Commercial Beekeeping Operations," which laid out a vision that addresses the risks of amitraz resistance created by off-label use.
The continuous use of off-label amitraz, with increasing dosages (as it becomes less effective), is likely to cause amitraz to lose its effectiveness, just as other products like coumaphos and tau-fluvalinate have become largely ineffective for controlling Varroa mites.
The Honey Bee Health Coalition continues to support innovation in honey bee health, including research, tool development and education aimed at helping beekeepers and farmers manage evolving threats.
The 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.
According to Noah Wilson-Rich, founder and chief scientific officer at the Urban Bee Lab, for the first time, commercial beehive losses have surpassed those of hobbyist and backyard beekeepers.'
The Boston-based lab found that two of every three beehives used for crop pollination have been lost.
'Last year marked the first time the U.S. surpassed the 50% threshold of beehive deaths, and this year is the first in which commercial beehive losses outpaced residential ones.
In 2014, the U.S. government set a loss threshold of 15%. 'We have well surpassed that, with losses now exceeding 60%, and a jump of around 10% in just the last year alone,' Wilson-Rich said.
In response, beekeepers have been rapidly replacing dead beehives by splitting one beehive into two or more, he said. Yet, these losses only take into account honeybees and ignore the 4,000 other species of native bees in North America, with populations going unmonitored without intervention.
His lab confirmed the mite responsible for the commercial bee die offs. Meanwhile, he said, 'My research team and collaborators around the world focus on AI sensors and blockchain technology to cure bees of diseases caused by mites, as well as to recover from pesticide exposure, as a next-generation approach to improving bee health.'
This article originally appeared on The Ledger: Mite blamed for 60% loss of bee colonies that pollinate food crops