One of the best ways to control pests in your garden is to encourage their natural enemies. Planting pollen and nectar plants, and providing protection for these beneficial insects, is a basic tenet of organic gardening, and a way to further increase the ecological diversity of your yard. We've listed the most common beneficial insects along with tips on attracting them to your yard.
The familiar round, orange spotted ladybug is just one of more than 400 species of lady beetles found in North America. Most ladybug adults and larvae feed on aphids and other soft-bodied insects. Adults are attracted to flower nectar and pollen, which they must eat before they can reproduce.
Pale green or brown lacewing adults have distinctive large, veined wings and feed mainly on flower nectar. Lacewing larvae, however, are voracious predators that feed on aphids, thrips, scales, moth eggs, small caterpillars and mites.
Adult: Joseph Berger, Bugwood.org
Larva: Whitney Cranshaw, Colorado State University, Bugwood.org
3. Hover Flies, aka flower flies or syrphid flies
Adults look like small bees with striped abdomens; the grayish or greenish slug- like larvae have pointed heads. Flower flies are attracted to flowers to feed on nectar and pollen. The larvae feed on aphids in tight places where other good bugs can't go, and are especially helpful in early spring, before other beneficial insects are active. Flower flies also pollinate strawberries and raspberries, producing larger fruits and higher yields.
Soldier Bug Nymph
4. Predatory Bugs, including minute pirate bugs, ambush bugs and assassin bugs (soldier bugs, big-eyed bugs)
These bugs prey on many insects, including tomato hornworms, thrips, spider mites, many insects' eggs, leafhopper nymphs, corn earworms and other small caterpillars. Pirate bugs are attracted by willows, buckwheat, corn and nectar and pollen from many flowers. Predatory bugs are attracted to bunch grasses, shrubs and other permanent plantings that provide them shelter. A unique lure is available to attract emerging soldier bugs to gardens.
5. Ground beetles
Large, long-legged, shiny blue-black or brown beetles that hide under rocks and logs during the day, and are fast-moving when disturbed. They feed on slugs, snails, cutworms, root maggots, and Colorado potato beetle larvae. Attract them by providing perennial ground covers, stones, or logs. Rove beetles resemble earwigs without pincers, and feed on many insect pests and like similar conditions to ground beetles.
6. Hunting and parasitic wasps
There are hundreds of species of wasps, including many that are so tiny you can barely see them. These mini-wasps often attack the eggs of pests, and are one of the most important insect groups that provide control of garden pests. They can be attracted by growing by pollen and nectar plants.
Photo: Scott Bauer, USDA Agricultural Research Service, Bugwood.org
7. Spiders: All spiders feed on insects and are very important in preventing pest outbreaks. The spiders normally found in gardens do not move indoors, nor are they poisonous. Permanent perennial plantings and straw mulches will provide shelter and dramatically increase spider populations in vegetable gardens.
Photo: Catherine Herms, The Ohio State University, Bugwood.org
8. Tachinid Flies
Although they look similar to house flies, tachinid flies are very important enemies of cutworms, armyworms, tent caterpillars, cabbage loopers, gypsy moths, sawflies, Japanese beetles, squash bugs, and sowbugs. Grow pollen and nectar plants to attract them.
Photo: Sturgis McKeever, Georgia Southern University, Bugwood.org