Yellowjacket wasps, like the hornets and paper wasps, live in colonies that increase in size throughout the summer. Finding and eliminating wasp nests around the house and in the landscape now prevents potentially bigger problems in the fall. Yellowjacket stings are quite painful, but the wasps are usually not aggressive except when disturbed at the nest.
Yellowjackets are honey bee size (about 1/2 inch long) and shiny with black and bright yellow markings. (Honey bees are golden or brown.) Yellowjackets build paper nests similar to hornets but either in the ground, a log or landscape timber or building wall or attic. Yellowjackets are commonly observed hovering back and forth at the small nest opening or around garbage cans and other areas where they forage for food. Nests may contain up to 5,000 workers, most of which never travel more than a few hundred yards from the nest while looking for food.
A yellowjacket wasp colony lasts only 1 year. A new nest is built from scratch each year and the previous years nest in not reused. The only wasps to overwinter are the fertilized queens. All the workers from a colony die with the first frosts.
Yellowjackets and other wasps are beneficial insects. They attack caterpillars and other insects to feed to their young. If a nest is located where it is out of the way and not likely to be disturbed, it should be left alone. If, however, a nest is located in a high traffic area such as along walks or near doorways, control is justified to reduce the threat of being stung.
Nests in walls or in the ground can be destroyed by placing an insecticide dust (e.g., Sevin or rotenone garden dust) in and around the nest entrance during the night. Do not plug a nest opening in a house wall until you are sure all activity within the nest has stopped. Control may take several days and retreatment in 2 or 3 days may be necessary.
This article originally appeared in the July 29, 1994 issue, p. 122.