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. The timespan from egg to adult can occur in 3-4 weeks. Multiple, overlapping generations occur annually in Virginia. Apply a dust of diatomaceous earth to control thrips. Minute pirate bugs and some lady beetle are predators of thrips.