AUBURN, Alabama — Yellow jackets have their second peak of activity in the fall. Many people encounter and experience painful stings from these wasps during outdoor activities such as tailgating, picnics and parties.
Dr. Xing Ping Hu, an entomologist with the Alabama Cooperative Extension System, said most yellow jacket species build nests in the ground. However, some construct nests in buildings, tree cavities and structural voids.
Yellow jackets begin new colonies by mated overwintered females who become foundress queens. Queens usually build new nests in May and contain about a dozen developmental cells. By fall, nests typically contain 300 to 120,000 developmental cells, depending on the species and environmental conditions.
In some places in the South, large perennial colonies, ruled by multiple queens and tended by thousands of workers, have been maintained. They can contain millions of cells, added Dr. Hu.
Tools for Managing
“Dust applicators are the most useful tools for managing yellow jackets,” Hu said. Hand dusters and air dusters are common applicators. Dusters should be operated by a pest control professional wearing protective garments.
Using a dust formulation can carry air deep into cavities and voids of wasp nests. Dust particles remain on the concealed surfaces awaiting contact with foraging yellow jackets, which, in turn, contaminate other nest mates.
Surface-treating yellow jacket nests with wettable powder insecticides accelerates the colony-elimination process. This permits same day nest removal, said Hu.
“If using aerosol and mist insecticides, such as pyrethirins and other botanical extracts to kill yellow jackets, apply directly to their bodies. Additionally, treat nests after dark when yellow jackets are contained within the treatment zone,” said Hu.
Although it is necessary to close off multiple entry points of wasps from structural voids to the living and work species, homeowners should never caulk close an exterior entrance to an active yellow jacket nest in a structure. This action only alarms the trapped wasps and causes them to seek out alternative escape routes to the outdoors.
Remember all female and worker wasps and bees can sting repeatedly, except for honeybees, said Hu. With occasional stings comes the likelihood of increased sensitivity to venom. Use caution around small areas of bare ground. They could house nests of yellow jackets. Exercise care and wear protective clothing when treating wasps.