Most encounters with yellowjackets occur when people are working around or inadvertently mowing over underground nests of the eastern yellowjacket or the common yellowjacket. The German yellowjacket is an exception; this species invades our space to build a nesting site. They typical paper nest is built in attics or wall voids. The first indication of their presence often occurs when large numbers (hundreds to thousands) of these yellow and black insects appear in living areas.
Fertile queens survive the winter in sheltered places and start new nests and colonies in spring. German yellowjackets occasionally reuse nests from previous years. While nests of our native yellowjackets contain several hundred individuals, colonies of German yellowjackets can number into the thousands. These aggressive wasps have a painful sting so they pose a significant problem.
Be suspicious of large numbers of yellowjackets indoors and have identification confirmed. So far, there have been few discoveries of the German yellowjacket in Kentucky, so it is important to keep up with its spread within the state.
Because of the large numbers of individuals in a colony and their fierce defensive reaction, it is best to leave the control to professional pest control operators.
By Lee Townsend, Extension Entomologist