Yellow jacket wasps feed their young liquefied insects, with caterpillars, flies and spiders comprising the largest food groups during most of the summer. The effect: Adios, garden pests!
This article is part of our Organic Pest Control Series, which includes articles on attracting beneficial insects, controlling specific garden pests, and using organic pesticides.
Yellow jacket wasps make irritating company at summer picnics, but they are extremely welcome visitors in the garden. These bright yellow-and-black striped wasps are slick and slender compared with honeybees, and are more likely to be found hunting among foliage than visiting flowers during the first half of summer. The food demands of growing yellow jacket colonies are so great that it has been estimated that more than 2 pounds of insects may be removed from a 2,000-square-foot garden by yellow jackets.
The benefits of yellow jackets come at a cost, because yellow jackets become dangerously aggressive when their nest is threatened. Nests are easiest to locate on warm summer mornings or evenings by carefully scanning the landscape for insects shooting up out of the ground. After you have located yellow jacket nests, decide whether they will stay or go. To neutralize a nest without using pesticides, cover the entry hole with a large translucent bowl or other cover, held in place with a brick. Be sure to approach yellow jacket nests at night, when the yellow jackets are at rest. Use flags or other markers to mark the locations of nests in acceptable places. Yellow jackets typically build new nests each year. Sometimes new yellow jacket nests appear in midsummer after old ones are damaged by foxes or other predators.
Yellow jackets wasps feed their young liquefied insects, with caterpillars, flies and spiders comprising the largest food groups in the yellow jacket diet during most of the summer. In late summer, yellow jackets start looking for flower nectar and other sources of sugar, which are necessary nutrients for the next season’s queens. Meanwhile, fewer young are being raised in the nests, which leaves many individuals with little to do. At this point yellow jackets become an obnoxious presence outdoors, whether they are trying to steal your sandwich or swarming over apple cores in your compost.
Simply allowing selected nests to remain in place is all you must do to receive free pest control service from yellow jackets. Coexisting peacefully with yellow jackets is another issue, especially if you grow tree fruits. Yellow jackets eagerly feed on fallen apples, pears and other fruits, so wear a light glove when cleaning up the orchard. Bury fruit waste beneath 2 inches of soil, or establish a fruit waste compost pile far from your house, where the yellow jackets can eat their fill.
You can use passive traps made from soda bottles to trap yellow jackets lurking on your deck or patio starting in early fall, should they be a problem. Most of these individuals will die of natural causes before the beginning of winter, so you have little to lose by trapping them.