Learn to tell the good bugs from the bad with OSU’s online guide

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Hoverfly. Pollinator and predator. (Photo by Lynn Ketchum.)
Last Updated: 
July 1, 2008

CORVALLIS, Ore. - You can teach yourself to identify beneficial predators in your garden with a hand lens and a new photo-illustrated guide to natural enemies.

A new guide has been published by the Oregon State University Extension Service and Oregon Tilth called “A Pocket Guide – Common Natural Enemies of Crop and Garden Pests in the Pacific Northwest” (EC 1613-E). The publication includes macroscopic photos of many types of natural predators in their various life stages, along with identification and observation tips.

Once you know the beneficial predators you want, plant the right plants. Research in OSU’s Department of Horticulture showed that some plants are better at attracting natural predators of pests in Oregon. Cilantro, yarrow, wild buckwheat, white sweet clover, tansy, sweet fennel, sweet alyssum, spearmint, Queen Anne’s lace, hairy vetch, flowering buckwheat, crimson clover, cowpeas, common knotweed, caraway and black locust have been proved to attract natural enemies of plant pests into an area.

Cilantro and sweet alyssum are particularly effective in attracting hoverflies, whose larvae are voracious aphid predators.

OSU’s Integrated Plant Protection Center (IPPC), has been working with Pacific Northwest growers to help them foster beneficial invertebrate predators, parasitoid insects and native pollinators on their farms. These tiny creatures can have a big impact controlling crop pests such as aphids, cutworms, earworms, slugs, leaf miners, spider mites and earwigs.

Bumblebees, and other natives pollinate many food crops. Enhancing their populations can significantly reduce the need for pesticides or dependence on honeybees.

Many of the same strategies to foster habitat for beneficial insects on farms can apply in home gardens, thereby reducing the need for pesticides in yards and gardens, explained Gwendolyn Ellen, coordinator of OSU’s Farmscaping for Beneficials Project.

Predators and parasitoids that control farm and garden pests include lady beetles, predator mites, hoverflies, the green lacewing, damsel bugs, stinkbugs, aphid-parasitic wasps and predacious ground beetles. The trick is to learn to tell the good bugs from the bad.

OSU’s Integrated Plant Protection Center and the Xerces Society of Invertebrate Conservation have been planting demonstration habitat for beneficial insects at the Natural Resource Conservation Service Plant Materials Center in Corvallis.

"Visiting the site is a good way to catch a glimpse of plants that work well to attract beneficial insects," said Ellen.

Online, there is an abundance of illustrated information about beneficial insects, natural pest control and integrated pest management from the OSU Extension Service, OSU IPPC, USDA and Xerces Society:

Author: Carol Savonen
Source: Gwendolyn Ellen