New Threats to U.S. Beekeeping: Yellow-Legged Hornet and Tropilaelaps Mite

As beekeepers, we’ve learned to manage challenges like varroa mites, small hive beetles, and disease pressures. But two new threats demand our immediate attention and action: the yellow-legged hornet (Vespa velutina), already established in Georgia and South Carolina, and the Tropilaelaps mite, which has been detected in regions near Europe, raising concern about potential introduction to North America.

In a recent livestream discussion, respected beekeeping experts Kaymon Reynolds (Tennessee’s Bees and founder of the NAHBExpo), David Peck, Ph.D. (BetterBee), Randy Oliver (Scientific Beekeeping), and Charles Linder (BeeCAUSE Alliance) emphasized the urgency of these threats and the critical role that beekeepers and pollinator enthusiasts can play in early detection and response.

The Yellow-Legged Hornet: Already Here and Spreading

What We’re Facing

The yellow-legged hornet was first detected in the United States in August 2023 near Savannah, Georgia, and has since spread into South Carolina. By the end of 2024, over 50 nests had been found and destroyed across both states, with 16 nests located in South Carolina alone.

In December 2024, a nest was discovered in York County, South Carolina—the first outside the Lowcountry region. This marked a significant jump northward and showed how easily these hornets can hitchhike on vehicles, boats, and other human transportation.

The York County case highlights both the threat and the power of awareness. A local beekeeper spotted hornets “hawking”—hovering near hives to capture returning foragers—and immediately reported it to Clemson University’s Department of Plant Industry. Officials tracked and destroyed the nest before it could produce new queens, likely preventing hundreds of new colonies from forming in 2025.

This example shows how individual vigilance can make a statewide impact.

How Yellow-Legged Hornets Devastate Bee Colonies

Yellow-legged hornets wait outside hive entrances and catch bees mid-flight. As colonies grow, these attacks intensify, sometimes deterring bees from foraging and weakening hives through stress and reduced resources.

Mature nests can contain several thousand workers and produce hundreds of new queens each fall. Hornets prey on all pollinators—not just honey bees—as they seek protein to feed larvae.

Identifying Yellow-Legged Hornets

Workers

Size: 0.7 – 1 in (18–25 mm)
Distinctive yellow legs (especially the lower portions)
Black or dark-brown body with a wide yellow-orange band on the fourth abdominal segment
Dark thorax with minimal yellow markings

Queens

Larger, about 1.2 – 1.4 in (30–35 mm) long

Nest characteristics

Large, egg-shaped paper nests, often high in trees or on structures
Mature secondary nests may reach 20–40 in (0.5–1 m) in length—much larger than nests of native hornets or wasps in the U.S.

Don’t confuse yellow-legged hornets with native species such as European hornets, cicada killers, or bald-faced hornets. When in doubt, photograph and report any suspicious sightings to your state agricultural department.

The Tropilaelaps Mite: A Threat on the Horizon

Current Situation

While Tropilaelaps mites are not present in North America, they are spreading westward through parts of Asia and Eastern Europe.
In 2024, T. mercedesae was confirmed in Russia’s Krasnodar region near the Black Sea and in the country of Georgia—establishing populations close to Europe’s borders. The mites have also been detected in Uzbekistan and are suspected in Iran and Turkey.

In 2025, community reports described a swarm of Apis dorsata (Asian giant honey bees) found on a container ship near the U.S. East Coast with suspected Tropilaelaps mites. The colony was reportedly removed before the vessel reached port. Although this has not been formally confirmed by USDA APHIS, it demonstrates how easily exotic pests could cross oceans if not intercepted.

Why Tropilaelaps Requires Our Attention

Research shows that T. mercedesae reproduces faster than Varroa destructor and spends less time on adult bees (shorter phoretic phase), allowing populations to grow quickly when brood is available.

Key biological differences

Bee impact: Infestation can impair learning, flight, and homing ability, and transmits viruses such as deformed wing virus.
Reproduction speed: Eggs laid roughly every 24 hours (vs. ~30 hours for Varroa).
Higher reproductive efficiency: A greater percentage of females are fertile, producing more offspring per generation.
Feeding behavior: Tropilaelaps Mites feed only on developing brood and can survive just 2–3 days without it—yet cause severe damage to larvae and pupae during that time.

Detection and Practical Guidance

Tropilaelaps mites are smaller, faster, and paler than Varroa, making them harder to spot. Alcohol washes and sugar shakes are unreliable for detection. Brood-uncapping and sticky-board monitoring are more effective.

Important Note: If you observe irregular brood patterns, deformed bees, or rapidly declining colonies despite varroa treatment, first ensure your varroa management was successful before considering other causes. Proper varroa monitoring and treatment remains your first priority. Understanding varroa biology and control is essential before worrying about threats that aren’t yet on our shores.

What Every Beekeeper and Pollinator Advocate Can Do

1. Set Monitoring Traps

Even if yellow-legged hornets aren’t yet in your area, setting traps provides early warning.
Make a simple DIY trap filled with “Georgia Juice”:

To make a basic hornet trap:

Cut the top third off a 2-liter bottle
Invert the top section and insert it into the bottom, creating a funnel
Mix 2 parts grape juice with 1 part dark brown sugar
Pour mixture into the bottle to about the halfway point
Hang near apiaries or in areas where you’ve seen large flying insects

For video instructions on trap making, visit Clemson University’s Hornet Herald Updates.

The goal is detection, not eradication—report catches to your state bee inspector or agriculture department.

2. Learn to Identify and Report

Yellow-Legged Hornets:

Georgia residents: Use the Georgia Department of Agriculture reporting form
South Carolina residents: Use Clemson University’s reporting tool
Other states: Contact your state apiary inspector or agricultural extension office

Tropilaelaps Mites: If you suspect Tropilaelaps infestation and have ruled out varroa-related issues, immediately contact your state apiary inspector and USDA APHIS.

3. Monitor Your Colonies

Watch for warning signs:

Hornets hovering near hive entrances (hawking behavior)
Bees reluctant to leave hives during good weather
Unusual activity of large flying insects around your apiary

4. Spread Awareness

Many early detections have come from new backyard beekeepers who trusted their observations and took action. Share information through your local clubs, garden groups, and social media. The more eyes watching, the greater our collective defense.

Why This Matters Beyond Beekeeping

These threats affect everyone, not just beekeepers. Honeybees and native pollinators are essential for:

Agricultural crop production (about one-third of food crops depend on pollinators)
Biodiversity and ecosystem health
Food security and agricultural economies

Yellow-legged hornets prey on all pollinators, not just honeybees, threatening the broader pollinator community that supports natural ecosystems and crop production.

Moving Forward with Knowledge and Action

This article aims to inform and empower, not alarm.
We’ve faced—and adapted to—varroa mites, small hive beetles, and other challenges through education and community coordination. Each has made us stronger beekeepers.

With yellow-legged hornets, early detection is our best tool. The success stories from York County and beyond prove that alert beekeepers can stop the spread.

With Tropilaelaps, we have advance warning. Knowing its biology and global movement helps us prepare surveillance systems long before it arrives—giving us a head start that earlier generations of beekeepers didn’t have.

What we need from you:

Stay informed about these threats.
Set and check monitoring traps.
Learn identification features.
Report suspicious sightings quickly.
Share this knowledge with others.

Experts emphasize that these invasive species are “great travelers,” capable of moving long distances through human activity. A single queen can hitchhike in cargo and establish a colony hundreds of miles away—but vigilant beekeepers can stop her before that happens.

Knowledge is power. The new beekeepers who spotted hawking behavior and acted made all the difference. You can too.

Take Action: Help Protect Our Bees from Invasive Threats

Preventing the spread of the yellow-legged hornet and keeping Tropilaelaps mites out of North America requires more than individual vigilance—it takes national awareness, research funding, and coordinated management.

Support initiatives like the BeeCAUSE Alliance petition urging stronger federal and state action against invasive pollinator pests.
Every signature shows that beekeepers, gardeners, farmers, and advocates stand united for pollinator health.

Together, we can raise awareness, strengthen prevention efforts, and safeguard the future of our bees.

Additional Resources

Stay vigilant. Stay informed. Together, we can protect our pollinators.