Beneficial Garden Insects
Posted: July 18, 2011
Thomas E. Walker
Director, Penn State Learning Center, Lewistown
County Extension Director, Juniata and Mifflin Counties
Most questions concerning insects and the home that come into the Extension Office are from homeowners very upset about an invasion of unwanted insects. However, for the gardener there are many insects that are your friend.
Beneficial insects can prevent or limit pest problems in your garden and lawn. These friends of the gardener can be categorized broadly as either insect predators or parasites. Predators include lady beetles, lacewings and spiders, yes spiders are a gardener’s friend. Common parasites are the tachinid flies and the braconid and ichneumonid wasps. When you must use an insecticide be very limited in its use and make sure it is one that is less likely to harm insect predators and parasites. There are several organic products along with insecticidal soaps that can be used that do not harm the beneficial insects in and around your garden.
Beneficial insects are most likely to remain in your garden if there is a ready supply of food. Most of these beneficial insects can be bought and introduced into your garden but it is probably cheaper and more effective if you can encourage the native ones to establish in and around your garden sites. You should plan your garden to feed the beneficial insects by choosing varieties of plants that will bloom throughout the growing season.
Plants that help attract beneficial insects to your garden include angelica, bee balm, buckwheat, calendula, candytuft, ceanothus, chervil, cilantro, clover, daisy, dill, erigeron, evening primrose, fennel, goldenrod, gypsophila, lovage, parsley, Queen Anne’s lace, rue, snowberry, sunflower, sweet alyssum, sweet cicely, thyme, valerian and yarrow.
Birds are also a big source of controlling problem insects in the yard and garden. Make sure you place trees, shrubs with berries, birdhouses and water features in and around your property to encourage birds to visit. Birds eat thousands of insects daily and can help control insect pests.
