Q: My garden is full of bugs! What is the best way to get rid of them? — Kathy, Cambria
A. You don’t want to eliminate all the insects in your garden. Get to know the beneficial insects in your garden and make them feel at home. Beneficial insects provide biological control by preying on destructive garden insects. They can help to keep your garden in balance without the use of insecticides.
The syrphid fly is a common beneficial insect. It resembles a bee and is sometimes called a flower fly or hover fly. It hovers and darts about sipping nectar from garden flowers. Syrphid fly larvae, however, are important predators of aphids and can consume hundreds of aphids in about one month’s time.
Parasitic wasps make up a large portion of beneficial insects. They range in size from microscopic to 3/4 inches long. Parasitoids lay eggs in or on their host. The eggs hatch and the larvae then feed on the host, eventually killing it. The braconid wasp, for example, lays eggs on tobacco hornworms, while other species of braconid wasps inject their eggs into aphids, cabbage loopers, and whitefly larvae.
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Lacewings and lady beetles are well-known garden predators. Lacewing larvae devour aphids, thrips, mites, mealybugs, caterpillars and other soft-bodied insects. The convergent lady beetle has a voracious appetite for aphids, especially in the larval stage of development. In their lifespan of about a year, ladybugs can eat 5,000 aphids. The larval stage resembles a small spiny, black alligator, devouring aphids at a remarkable rate.
Many other beneficial insects prey on garden pests. The minute pirate bug, bigeyed bug, predatory mites, spiders, and predatory nematodes play a part in keeping your garden in balance.
Encourage these good guys by planting a variety of flowering plants to attract them and provide a lasting resource. Plants with varying bloom times can provide a food source for beneficials throughout the year and will sustain the population even in the absence of seasonal garden plants. Beneficial insects are especially partial to buckwheat, California lilac, sweet alyssum, yarrow, and the flowers of cilantro, chervil, dill, fennel, lovage, and parsley.
Attract beneficial insects to your garden and perhaps they’ll stay for lunch!