Yellowjackets have a well-deserved reputation for being aggressive since they often sting when defending their nests or when they encounter people while out scavenging for food.
This time of year, yellowjacket colony populations are increasing, and people may encounter them more frequently. Some yellowjacket species live in underground nests and can be a problem to people mowing the lawn or to children playing on it. Other kinds of yellowjackets may live in between voids in walls and ceilings of houses, coming into contact with people who pass by.
Sometimes paper wasps are mistaken for yellowjackets, but these insects are much less aggressive and more easily dealt with.
If you have a wasp problem and need management tips, consult the Pest Notes: Yellowjackets and Other Social Wasps. Although yellowjackets can be a nuisance, some species do kill large numbers of plant feeding insects and nuisance flies and are considered beneficial predators.