![]() |
| Yellowjacket photo by Whitney Cranshaw |
Whitney Cranshaw, Entomology Professor and Extension Specialist from CSU tells us that the western yellowjacket (V. pensylvanica) is, by far, the most important stinging insect in Colorado. Late in the season, when colonies may include up to 200 individuals, they become serious nuisance pests around outdoor sources of food or garbage. The western yellowjacket is estimated to cause at least 90 percent of the “bee stings” in the state. Yellowjackets (Vespula spp.) are banded yellow or orange and black and are commonly mistaken for honey bees, but they lack the hairy body and are more intensely colored. Yellowjackets typically nest underground using existing hollows. Occasionally nests can be found in dark, enclosed areas of a building, such as crawl spaces or wall voids.
Yellow jackets are social wasps, living in a community rather than alone. But every spring these communities have to be redeveloped because all the wasps except fertile queens died over the winter. In the spring queens emerge and begin searching for suitable nesting sites.There has been some success using baits and traps for control of yellowjackets. The western yellowjacket is attracted to the chemical heptyl butyrate, which is included as a lure in many wasp traps. Such traps can be helpful when used early in the season, when the number of yellowjackets is small and the colonies are struggling to become established.
So put out those traps! Get a head start on controlling Vespula pensylvanica! Here’s a fact sheet about all the nuisance wasps and bees.






