Adult: Yellow or brownish, winged, active, about 1/25 inch long. Larva: White, wingless, looks like adult but smaller.
Common Host Plant(s)
Onion. Also, bean, beet, carrot, cabbage, cauliflower, celery, cucumber, melons, peas, squash, tomato and turnip.
Adults and larvae suck out juices from plants. White blotches appear on leaves. Tips of leaves wither and turn brown.
Throughout United States.
Onion thrips overwinter as adults and immature nymphs in plant debris in or near fields. Onion thrips deposit their eggs in leaf tissue. Onion thrips experience four instars. The first two instars feed on the onion plant. Following these two immature stages a pre-pupal, non-feeding, but mobile stage occurs at the soil line around bases of plants or in leaf axils. The time span from egg to adult can occur in 3-4 weeks. Multiple, overlapping generations occur annually in Virginia.
Some varieties of sweet onion are resistant to thrips.
Apply a dust of diatomaceous earth to control thrips. Minute pirate bugs and some lady beetle are predators of thrips.
Treat with a registered insecticide when thrips appear in damaging numbers.
Virginia Cooperative Extension materials are available for public use, reprint, or citation without further permission, provided the use includes credit to the author and to Virginia Cooperative Extension, Virginia Tech, and Virginia State University.
Issued in furtherance of Cooperative Extension work, Virginia Polytechnic Institute and State University, Virginia State University, and the U.S. Department of Agriculture cooperating. Edwin J. Jones, Director, Virginia Cooperative Extension, Virginia Tech, Blacksburg; M. Ray McKinnie, Administrator, 1890 Extension Program, Virginia State University, Petersburg.
April 25, 2011