Adult: Yellow or brownish, winged, active, about 1/25 inch long. Larva: White, wingless, looks like adult but smaller.
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 timespan 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.
Notice: Because pesticide labels can change rapidly, you should read the label directions carefully before buying and using any pesticides. Regardless of the information provided here, you should always follow the latest product label when using any pesticide. If you have any doubt, please contact your local Extension agent or pesticide dealer for the latest information on pesticide label changes.
Disclaimer: Commercial products named on this site are for informational purposes only. Virginia Cooperative Extension does not endorse these products and does not intend discrimination against other products which also may be suitable.
Prepared by Alexandra Spring and Eric Day (Modified from a publication by the USDA)