Vespula spp.; Dolichovespula spp.
Adult workers about 3/8″ to 5/8″ (10 – 16 mm) long depending on the species with their respective queens about 25% longer. Abdomen usually banded with yellow and black, several species with white and black, and 2 northern species also marked with red. Wings folded longitudinally at rest. The yellow jacket picture shows the most common coloring.
Places Most Commonly Found:
The overwintering queen will usually select either a subterranean or aerial nesting site. Most of the pest species are ground nesting. However, the German yellowjacket usually nests in buildings in the United States, the western yellowjacket usually nests in buildings and the aerial yellowjacket commonly attaches its nests to shrubs, bushes, houses, garages, sheds, etc. Those nesting in the ground typically select areas bare of vegetation or else clear an area around the entrance. There are nest entrance guards to protect the colony. Overwintering queens will often enter the living space of buildings seeking warmth, or in the spring when they are looking for a nest site or just trying to get back outside. Every yellow jacket stings.
Most Active Period:
Only inseminated queens overwinter and do so in sheltered places. The adults are represented by workers which are sterile females, queens and males and usually appear in late summer. Nest size will usually contain 1,000 to 4,000 workers at its peak. Reproductive cells will be formed late in the summer and early fall and the nest enters a declining phase. The newly emerged queens and males leave the nest and mate. The founding queen and all of the workers die in late fall to early winter. When active the yellowjacket bites.
Difficulty of Control:
Easy to control if the nest is located and can be treated with pesticide during the evening, night or early morning.