Plant Protection Today: USDA Supports States’ Yellow-Legged Hornet Hunters and Pollinator Health

Robust Surveys and Public Reports Underpin Eradication Efforts

By Sharon Lucik

Last August, a Savannah, GA, beekeeper discovered an unusual-looking hornet outside of his apiary, and reported it to the Georgia Department of Agriculture (GDA). As it turned out, it was an invasive yellow-legged hornet and the first confirmed detection in the United States. Three months later, South Carolina officials captured their first hornet. So where are we now? Have there been other detections? Are these hornets a threat to pollinators and agriculture? USDA’s National Policy Manager Anne LeBrun answered these questions and others, and provided a snapshot from this developing situation.

“Here’s the latest,” said LeBrun. “GDA found and eradicated 11 nests since their initial detection. This year they’ve set about 1000 survey traps in six counties—most are in Chatham County, GA. As of June 21, they’ve caught more than 40 hornets. It’s a different situation across the Savannah River in Jasper and Beaufort Counties SC. There, South Carolina’s plant industry staff have trapped four hornets, but they haven’t found any nests yet. A Bluffton, SC, resident however found and removed a nest on their house. That nest was sent to USDA’s Pest Identification Technology Laboratory, where it was confirmed as a yellow-legged hornet’s nest.”

The yellow-legged hornet is a social wasp native to Southeast Asia. Its nests look like paper cones with a single entrance, and they hang in trees and on structures such as barns, garages and sheds. This species feed on insects, including honey bees. If they become established in the United States, they could threaten our domestic and feral honey bees, and other native pollinators. Their presence could also disrupt the pollination of many crops.

USDA has provided the States with money through rapid response funding for survey and eradication activities, and public outreach. USDA’s National Identification Services staff is also testing DNA from yellow-legged specimens to determine where they came from. So far, the testing has not identified a country of origin but likely ruled out ancestry with invasive yellow-legged hornet populations in Europe. Additionally, local staff continue to assist with weekly trap checks.

“These hornets aren’t more aggressive towards people than any of our native hornets; however, they are an apex predator in the insect world. That means they are at the top of a food chain without natural predators, and honey bees are at risk,” LeBrun explained. “Yellow-legged hornets display stalking behaviors around honey bees. They hover outside a honey bee’s hive waiting for foraging bees to return. That’s when they attack and carry off the bees to their own colony to feed their developing brood. This behavior is sometimes called ‘hawking’.”

There’s no telling what lies ahead. However, these next several months will certainly help us find a path forward. In the meantime, here’s hoping the story of the yellow-legged hornet is a short one.

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