Yellowjackets

Yellowjackets are yellow and black, 1/2-inch long wasps. Their nests are usually located in the soil, where they commonly occupy an abandoned, rodent burrow or within the walls of buildings that they enter through a crack or other opening. These nests start in the spring from an overwintered queen and by fall grow to colonies that contain 4 to 10 thousand wasps.

These wasps feed themselves on flower nectar and also collect meat to feed to the developing larvae in the nest. This meat is usually in the form of killed insects, such as flies and caterpillars, but may also include hamburger and other meat from garbage cans, as well as dead mice, birds and other animals. Their habit of scavenging garbage cans for food brings them into contact with people, making stings with this wasp more likely than with other species. In the fall, their search for food becomes very intense once cooler temperatures remove most natural food sources such as nectar in flowers and other insects, making them even more numerous around humans.

As winter approaches, the nests die out; young overwintering queens that left the nests earlier in the fall are the only yellowjackets that survive the winter. Unfortunately, before the nest dies in the fall, wasps in nests that are located in wall voids will commonly be attracted to the warmth inside houses and will enter the living area of the house. In the late fall, reports of about 200 of these wasps entering the living area of the house during the day for about a week are not unusual.

Control: Yellowjacket nests in the soil can be controlled by soaking the nest with diazinon in the evening when the wasps are less active. Covering the nest opening with a shovelful of soil after applying the diazinon makes the application more effective. Nests in wall voids can be eliminated by treating the outside opening and the area around it with carbaryl (Sevin) dust. Do not plug the hole with the Sevin dust since this treatment relies on the wasps carrying the dust into the nest. The nest will usually be dead within a week after treatment and can be left inside the wall because it contains no honey to attract mice or other insects. Since the nest is made of several layers of paper, it actually adds insulation to that section of the wall.

Late Summer 1998
Asian Longhorned Beetle Found in Chicago | White Grub Update | Management Practices for Late Summer/Early Fall | Yellow Jackets | Bug Bites: Flower Chewers | Lawn Care Calendar | Cybergarden Sites | Hort Shorts | Hort Tips | Health Update: The Heat Is On! | Locally Grown: Blueberries | At the Farmers' Market: Cut Flowers | Health & Household Tips | Did You Know?

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