Yellowjackets hunt caterpillars, many of which are crop and forest pests, making yellowjackets distinctly beneficial to human interests.
If yellowjackets are a problem for you, yellowjacket traps can offer some relief. Sealing garbage well helps, also. Individual yellowjackets — in a car, or on the lip of a soda can — can be gently nudged away with a piece of paper. Never swat a yellowjacket on your body — it could prompt a sting.
Although these wasps do much that benefits humans, their capacity for colonial, defensive stinging makes them a major pest when they nest near people, especially since some people are allergic to bee and wasp venom. Signs of a severe allergic reaction may include swelling of the face, lips, or throat; breathing difficulties; hives or itching in areas not near the sting; sudden drop in blood pressure; dizziness or lightheadedness; nausea; or loss of consciousness. Also, if a nonallergic person is stung many times at once, it may be enough to produce a severe allergic reaction. If you think you are having a severe allergic reaction to a wasp sting, seek immediate medical help, including calling 911 or other emergency services, as you may not be able to drive yourself to a medical provider. If a doctor has prescribed an emergency epinephrine autoinjector for you, use it right away, as prescribed.
Many people encounter yellowjacket nests when they are mowing a lawn and fail to notice the wasps flying in and out of the hole in the ground that is the entrance to their nest burrow. Before mowing, it's always a good idea to walk the area to look for rocks, sticks, trash, and the nests of animals (including yellowjackets).
If you want to eliminate a yellowjacket nest, we recommend consulting a licensed exterminator.
Yellowjackets' love of sweets causes them to be attracted to soda cans. Sometimes people are stung on the lips when they sip soda out of a can that a yellowjacket is visiting.
If yellowjackets seem unreasonably "mean," remember that they are defending their home and family from what their brains perceive as potential destruction. Many of us are prepared to do basically the same thing, on a personal and even a national level.
People rightly fear yellowjackets and other social wasps that are capable of stinging en masse. But as with many animals that can powerfully affect humans, these wasps have earned a place of respect in our culture. Note, for instance, the many sports teams that are named "yellowjackets," "hornets," and so forth.
A closely related genus of wasps, Vespa, occurs in Eurasia, with one species, the European hornet (V. crabro) introduced to North America (including Missouri). Vespa means "wasp" in Italian, and it also happens to be the name of one of the world's most iconic makes of motor scooters, the Vespa by Piaggio.
Folklorist Vance Randolph recorded an oldtime Ozark charm for protecting yourself from yellowjackets: "Jasper whisper jacket! / You caint no more sting me / Than the Devil can count sixpence!"