Every January, Charles Linder travels from Illinois to Idaho to retrieve thousands of bee hives from a temperature-controlled storage facility.

He loads boxes of hives onto a semi truck headed west for almond season, the first of many stops his bees will make on a cross-country pollination tour.

But two winters ago, Linder opened those boxes and discovered that around 90% of his bees were dead.

“It was gut-wrenching,” he said. “There’s an emotional loss from that. There’s a frustration that you didn’t do your job right. And then the economics hit.”

His experience was not unique. The western honeybee, Apis mellifera, is the workhorse of American agriculture, pollinating more than 130 types of nuts, fruits and vegetables — some $15 billion worth of the nation’s crops — every year. But as the commercial beekeeping industry in the United States has grown, so too have its losses. Nearly 56% of managed honeybee colonies died off in the past year, according to preliminary results released in June by the U.S. Beekeeping Survey. That is the highest rate recorded since annual reporting began in 2011.

“Beekeepers, especially commercial ones, experienced a particularly bad year,” Geoff Williams, an entomologist at Auburn University who coordinated the survey, wrote in an email. The results, he said, highlight “the tremendous strain honeybees and beekeepers are facing to safeguard our food supply.”

Honeybee health has been negatively affected by a combination of factors: unpredictable weather, habitat loss, pesticides and disease. But one of the

biggest threats is a parasite known as varroa destructor, a Southeast Asian mite that arrived in the United States in the late 1980s. In June, the U.S. Department of Agriculture announced that viruses spread by varroa were a leading cause of the past year’s colony collapses, with an estimated financial impact of $600 million for beekeeping businesses.

While American beekeepers search for solutions, another, potentially worse threat looms: Tropilaelaps mites, which also hail from Southeast Asia and have been making their way across Asia and into Europe. Should they arrive in North America, experts fear, the mites would wreak havoc on honeybees and ravage a large part of the nation’s food supply.

“The beekeeping industry in the United States, as we know it, would completely collapse,” said Patty Sundberg, president of the American Beekeeping Federation.

In recent years, as concern about Tropilaelaps has grown, scientists have ramped up research on the mite. The federal government and honeybee nonprofits have funded much of that work, as well as trainings to educate beekeepers, some of whom are now pushing for the United States to have better protection against the mites.

Despite these efforts, stakeholders fear that American honeybees cannot survive another parasite. “We already have a perfect storm of problematic issues for our bees,” said Sammy Ramsey, an entomologist at the University of Colorado Boulder who has spent years sounding the alarm about Tropilaelaps mites.

Mass firings and funding cuts by the Trump administration may have further undermined the nation’s readiness. Beekeepers worry about what that could mean for commercial pollination and the nation’s produce supply.

“From the blueberries of Maine to the avocados of San Diego County, we always show up,” said John Miller, a fourth-generation beekeeper in North Dakota who owns about 18,000 colonies. “I don’t know what’s going to happen the year we don’t.”

BUSY BEES

Although there are multiple species of honeybee, Apis mellifera, which now lives on every continent except Antarctica, became a beekeeper favorite because it is relatively docile, adaptable and productive. But such benefits come with a tradeoff: a reduced ability to deal with parasites and disease.

And in the mid-20th century, the varroa mite jumped from its original host, the eastern honeybee, to the western honeybee, with devastating consequences.

The tiny mites, which resemble amber sesame seeds, feed on the fat of both developing and adult bees, leaving them more vulnerable to pesticides, malnutrition and viruses, including those carried by the mites.

Yet the threat brewing on the other side of the Pacific might make varroa seem almost quaint.

Two species of Tropilaelaps mites have jumped from their original hosts to western honeybees. These mites are smaller than varroa but even more fearsome, with a faster reproductive rate and mouthparts that tear multiple wounds into bees’ bodies.

They had one notable limitation, a tiny Achilles’ heel that made American beekeepers feel safe. Unlike varroa, Tropilaelaps did not seem to feed on adult bees, and dined solely on a colony’s developing young, known as the brood. In tropical Southeast Asia, queen bees often lay eggs year-round, providing the mites with a steady source of food. But in more temperate regions, egg-laying tapers off during the coldest winter months. Without bee brood to feed on, the mites simply would not be able to survive the winters in cooler climates, scientists assumed.

“We always felt it would be a Southeast Asian problem,” said Jeff Pettis, a former USDA entomologist who is now the president of Apimondia, an international beekeeping federation.

They were wrong. In recent years, the mites have been marching north and west. Climate change could be a contributing factor, allowing some queens to extend their brood-rearing seasons. But the mites have also turned up in places with colder climates, including South Korea, China, western Russia and the country of Georgia.

Most experts now agree that it’s only a matter of time before Tropilaelaps migrates to North America. According to Denis Anderson, an Australian bee scientist who has studied the mites, “it’s something that will eventually get into bees worldwide.”

HIVE MINDS

Since 2009, the Animal and Plant Health Inspection Service at the USDA has conducted an annual bee survey to document diseases, parasites and pests in the United States. So far, there has been no evidence of Tropilaelaps.

But in the past few years, scientists have intensified efforts to prepare for its possible arrival. “The best possible time for you to have an emergency response plan is before the emergency occurs,” said Ramsey, who is developing a swab test, analogous to those used for COVID-19, so beekeepers can check their hives for the mite. Williams leads a brood monitoring program to help track where Tropilaelaps may have access to a food supply to last the winter.

Tropilaelaps mites can’t feed on adult bees, but they can survive on them long enough to cross a border.

The United States strictly regulates honeybee imports, allowing entry solely to adult bees from Canada and New Zealand, both of which seem to be Tropilaelaps-free. But it is unclear how long that will last.

In 2024, the Canadian government closed its border to bees from Ukraine after officials failed to confirm that Tropilaelaps was not present in the country. But Canada still allows bee imports from Italy, which is in the path of the mite’s expansion west.

Beyond sanctioned imports, the mites could arrive via bees that are smuggled into the country or happen to stow away on ships.

Many believe the mite’s presence in North America is only a matter of time.

“It could be years from now, it could be days from now,” Ramsey said. “It could be that they’re here right now. And because we don’t have a diagnostic monitoring system, we’d never notice.”

Key questions about Tropilaelaps remain, including how it travels, how it is surviving cold winters and how best to mitigate its spread.

But changes across the federal government are posing new challenges. Firings at the U.S. Department of Agriculture have included scientists who specialize in honeybee health.