Family: Braconidae, Ichneumonidae, Eulophidae, Aphelinidae, Trichogrammatidae
These wasps are a large and diverse group of parasitoids. Most are extremely small, under 0.5-inches long and attack small insects such as aphids.
Giant ichneumon wasp. Image credit: Boris Hrasovec, Faculty of Forestry, Bugwood.org
Braconid wasp cocoons on a tobacco hornworm. Image credit: Clemson University – USDA Cooperative Extension Slide Series, Bugwood.org
Parasitoid wasp attacking an aphid. Image credit: Frank Peairs, Colorado State University, Bugwood.org
- Beneficial arthropods can prevent or limit pest problems in the yard and garden.
- These beneficial wasps can be categorized broadly as either insect predators or parasites.
- Common insect parasitoids include flies and small wasps.
- When insecticides are needed, choose ones that are selective and less likely to harm beneficial insects and mites.
Usually, female wasps parasitize hosts by paralyzing an adult insect or larva and laying eggs inside. Upon hatching, the wasp larvae feed on and eventually kill the host insect. Important aphid parasitoids include members of the families Aphelinidae and Braconidae. Larger parasitoid wasps attack caterpillars or wood-boring beetles. Wasps in the family Trichogramma are commonly used for biological control as well and many can be commercially purchased.
Gardeners are more likely to see the results of parasitoids’ activities, rather than the wasps themselves. For example, aphids that are parasitized by these wasps typically have a swollen, balloon-like appearance and turn brown or black. These parasitized aphids are called “mummies.” Other braconid wasp species spin conspicuous pupal cocoons after emerging from a host.
CSU Extension Fact Sheet
Download or view the CSU Extension’s PDF fact sheet for your reference.