Braconid wasps play an important role in controlling insect pests. Braconids are beneficial insects that lay their eggs inside or on host insects, and then the maggot-like wasp larvae weaken the host pest.
This article is part of our Organic Pest Control Series, which includes articles on attracting beneficial insects, controlling specific garden pests, and using organic pesticides.
North America is home to nearly 2,000 species of these non-stinging wasps, which are also found in Europe and other temperate climates. Adults are less than half an inch long, with narrow abdomens and long antennae. Most are black, but some are yellow-orange, and one common species has a red body with black wings. Adult braconid wasps lay eggs inside or on host insects; the maggot-like larvae then feed on the prey from the inside. Like other wasps, braconids are most active on warm days, and tend to be most abundant where summers are warm and humid.
Adult braconid wasps consumer flower nectar and pollen. They provide effective caterpilllar control, aphid control and more. Braconids lay eggs on numerous pest species, such as caterpillars (including cabbage worms and tomato hornworms), aphids, flies, beetle larvae, leaf miners and some true bugs. A female braconid wasp can lay from 50 to 200 eggs, so this beneficial can have significant positive effects in the garden. As the wasp larvae feed inside their hosts, they weaken them and make them incapable of reproducing.
Grow an abundance of flowers and herbs that produce nectar from numerous small florets, such as sweet alyssum, chamomile, feverfew, catnip and buckwheat. When allowed to produce flowers, dill, fennel and other members of the carrot family also attract braconid wasps. One type of braconid that specializes in parasitizing aphids, Aphidium colemani, is available commercially for use in greenhouses.