Conservation. Leaving natural plant communities undisturbed on field borders and other noncrop areas can help maintain existing populations of beneficial mites, spiders, insects, etc.
Nectar and pollen sources. Alternate food sources provided throughout the cropping season can extend the life span of beneficials, allowing them to produce more eggs and to parasitize more pests.
Alternate hosts and prey. When crop pests are not present, other plants and the insects they host can maintain populations of beneficials. Cover crops, hedgerows, windbreaks, and fieldside weeds are good reservoirs for alternate prey such as aphids and thrips.
Habitat shelter. A plant's architecture can influence its suitability as an overwintering site and can affect microclimate, since windbreaks and shade can modify temperature and moisture conditions. Also, flower shape and size can attract beneficials. For example, many predators and parasites such as ladybugs and wasps have short chewing mouth parts and need shallow flowers to access nectar. In contrast, butterflies have long mouth parts that can extend into deep tubular flowers.
Flowering time. Species that bloom at different times are combined to provide season-long shelter and food for beneficials. Food source. A plant's potential for providing nectar, pollen, alternate prey, and honey dew from aphids is considered.
Survivability. The plant's ability to withstand machinery traffic, grass competition, and low maintenance conditions is important. Hardy per-ennials and self-seeding annuals are prime candidates for good survival.
Few pests. Plants are screened for their potential to harbor many beneficials but few crop pests.
White sensation cosmos, (Comp-ositae, Cosmos bipinnatus), draws spiders, ladybugs, wasps, hover flies, insidious flower bugs, and lacewings.
Tansy, (Compositae, Tanacetum vulgare), attracts many flies, ladybugs, lacewings, insidious flower bugs, and small wasps. This plant harbors the tansy aphid in large numbers and provides a good alternate food source for predators.
Caraway, (Umbelliferae, Carum carvi), invites wasps, syrphid flies, lacewings, and insidious flower bugs.
Dill, (Umbelliferae, Anethum graveolens), attracts insidious flower bugs, ladybugs, and hover flies.
Sweet fennel, (Umbelliferae, Foeniculum vulgare), lures hover flies, parasitic wasps, ladybugs, and spiders.
Spearmint, (Labiatae, Mentha spicata), draws various flies, predatory wasps, and spiders.
Buckwheat, (Polygonaceae, Fago- pyrum esculentum), attracts hover flies, minute pirate bugs, predatory wasps, tachinid flies, ladybugs, and syrphid flies.
Ladybugs. (Coccinellidae) These insects eat aphids and other species of small insects and eggs.
Insidious flower bugs. (Anthocoridae) Also known as pirate bugs, they feed on insect eggs, small larvae, thrips, and mites.
Parasitic wasps. (Braconidae, Chalcididae, Trichogrammatidae, etc.) There are many different wasp species, the most well-known is Trichogramma. They kill pests by laying eggs inside pest eggs, larvae, or adults.
Lacewings. (Chrysopidae) Adults are not predatory, but their larvae feed on small caterpillars, mealybugs and scale, moth eggs, and aphids.
Flies. (Tachinidae, etc.) Some are pests, some are beneficials, depending on the species. The most valuable beneficial flies are tachinids, which parasitize stink bugs and the caterpillar stages of various moths and butterflies.
Hover flies. (Syrphidae) These flies are commonly known as syrphids; their larvae attack many types of aphids.
For more information:
Rodale Institute Experimental Farm
611 Siegfriedale Road
Kutztown, Pa. 19530 U.S.A.