Use caution with defensive yellowjacket colonies

Dr. Eric Paysen, Technical Services Manager, Syngenta Professional Pest Management

Large colonies of yellowjackets (Vespidae) can pose huge risks to people and pets in the vicinity. In most of North America, the entire colony, except the queen, dies in the fall. Each spring, the worker caste must be rebuilt from eggs laid by the overwintering queen.

However, in temperature-controlled environments like wall voids, heated outbuildings, attics or garages, the colony can survive the winter. These colonies can grow to epic proportions, with more than 100,000 workers.

Because of this, watch out for yellowjacket workers flying out from cracks and crevices on your customers’ properties. Large colonies are notoriously defensive, so always use extreme caution.