Each fall, the colony produces males and females that mate and the females become next year’s queens. Only the over the wintering queens survive in protected sites such as under loose bark, in tree cavities, and in-wall voids of buildings. All other colony members produced in the current year will perish.

In the spring, the emerging queens establish new nests in aerial cavities, deposit eggs in cells they have constructed, and feed the first batch of larvae. The larvae mature, pupate in their cells, and then emerge sterile female workers.

These workers take over the responsibility of foraging for food to feed the young larvae, collect cellulose to expand the nest, and protect the nest from external threats. Typical food for the young include crickets, grasshoppers, large flies, caterpillars, and the workers of other yellow jacket species.

European hornet colonies often contain 300 or more workers by September or October (maximum of 800–1,000 workers). It is not unusual for workers to bounce off of external lights or house window panes during summer nights. Although the workers will sting if handled, they are not normally aggressive unless the colony is threatened.

In addition to the hazard created by their stings, the hornets will also damage various trees and shrubs by girdling the branches and twigs to gather bark for nest building and to obtain nourishment from the sap.

For the treatment of European hornets in wall voids of buildings. Be certain NOT to plug the hornets’ entrance because they may chew through interior wall coverings in an attempt to escape and enter the living area.

 You can call our emergency number after hours for help with this pest. The picture taken was at 10 pm. in the home with a horrified family. Do not attempt to swat or spray these insects they will turn aggressive. Avoid hive as the distance may be assumed as aggression.