Natural Biological Control

- These bugs can be a big help to gardeners -

Summary: Gardeners should do all they can to encourage natural biological control of garden pests. These organisms can do much of your pest control for free. Both predatory insects and mites as well as parasitic insects are a gardener's best friend.

Jack DeAngelis, PhD

OSU Ext. Entomologist (ret.)

Insect and mite pests have many natural predators and parasites that normally keep pest numbers in check. Predators and parasites are sometimes called natural enemies or "beneficials". Predators kill live prey while parasites do not immediately kill their hosts. When predators or parasites suppress a pest population it is called biological control.

Parasites tend to weaken individuals and populations, and may make them more susceptible to other factors like disease. Predators, on the other hand, kill individual pests. When pest numbers increase a predator or parasite often responds to bring the numbers down. Predator numbers respond to an increase, or decrease, in the availability of prey and these interactions are the basis for the field of insect ecology.

common names and misnomers: ladybird beetles, lady bird beetles. ladybugs, hover flies

Pea aphid mummy. This aphid was parasitized by a tiny wasp whose larva developed inside the aphid. The wasp emerged through the hole cut in the aphid's back.

Natural enemies in your garden

There are thousands of predatory and parasitic insects and mites. For gardeners the most important ones are lady beetles, syrphid flies, lacewings, predator mites and certain wasps. The best sources of natural enemies for your garden are native plants in the area. Predators and parasites that migrate off native, natural areas into the garden are adapted to local conditions and will do the best job of pest control.

If possible, leave small areas of your landscape unmowed and not treated with pesticides, and allow a natural succession of plants to develop which may include some weedy species. These areas will serve as a natural enemy nursery for the rest of your landscape.

Also, avoid harsh insecticides that wipe out beneficial species along with pests. What frequently happens is that pests return faster than natural enemies and the pest populations explode. Natural Insecticides are easier on beneficial species and should be your first choice whenever possible.

Related Articles

Natural Enemies Guide - A brief introduction to predators and parasites.

Don't forget to bookmark us for next time - press ctrl-D in most browsers.

Home - Privacy Policy

Mission: To provide accurate, up-to-date and unbiased information for solving common insect and mite problems around your home, business and landscape using least-toxic methods.

Please see the Disclaimer statements as well.