Gardening Principles | Home & Garden
Wasps are a large family of insects that includes hornets and yellow jacket wasps. All are ferocious predators of many common garden pests. Some family members, unfortunately, also damage the fruits and cause painful bites.
Yellow jackets and other wasps feed on fly larvae, beetle larvae, ants and caterpillars. If you think their benefits to your garden outweigh the risk of getting stung, do not destroy their paper nests unless they are near an outdoor living space or a family member be allergic to insect bites. Yellow jacket wasps nest in the ground and can make mowing dangerous. Spray an aerosol pesticide that kills wasps in the nest at night when the wasps are resting.
Many beneficial wasps are so small (usually less than ¼ inch long) that you may not be able to see them. But you can sometimes find their work. All beneficial wasps are parasitoids, which means that they lay their eggs on an insect host, usually eggs or larvae. The developing wasps then form cocoons on the host. If you see a larva or caterpillar with small, rice-like pouches, you have beneficial braconid wasps in your garden.
You can buy beneficial wasp eggs from mail order insectaries and garden catalogs. Follow the instructions for releasing them – some wasps need to be released over a period of several weeks. Don’t bother buying them unless you’re sure the pests they use as nurseries are in your garden.
Encourage beneficial wasps to stay by growing adults’ favorite nectar sources, which include many flowers, such as goldenrod, clover, coreopsis, daisy, sunflower, yarrow, cilantro, parsley and tansy.
To avoid bites, do not use scented products when working in the garden, especially perfume, scented sunscreen or hairspray. Also avoid light blue or yellow clothing and work outside in the evening when wasps are less active.
To keep wasps away from fruit, cover ripening fruit with muslin or pantyhose tied at both ends, directly on the tree.
To get rid of yellow jackets that appear from unknown places, try this. Cut the top off a plastic bottle and invert it inside its base to make a funnel, securing the edges with tape if necessary. Pour sugar water into the bottle and hang it in a tree or simply place it where yellow jacket wasps are active. The wasps will climb to reach the liquid and either drown or be unable to get out.