How to Manage Pests
UC Pest Management Guidelines
Scientific Names: Western
flower thrips: Frankliniella occidentalis
Thrips are very small, slender insects that are best seen with a hand lens. Mature western flower thrips are 0.06 inch (1.5 mm) long, while onion thrips are slightly smaller at 0.05 inch (1.3 mm) long. Western flower thrips is more prevalent than the onion thrips.
The most distinctive characteristic of thrips is two pairs of wings that are fringed with long hairs. Adults are pale yellow to light brown in color. Immature stages have the same body shape as adults but are lighter in color and are wingless. Western flower thrips adults have red-colored pigment in their eyes and onion thrips eyes are gray.
Thrips have a very extensive host range, including alfalfa, cereals, cotton, onions, garlic, broadleaved crops and numerous weeds and flowers.
Feeding by thrips leaves marks on the calyx that eventually turn silver. The silver coloring is cosmetic but creates an unhealthy look on darker colored fruit. Thrips vector Tomato spotted wilt virus.
If possible, avoid planting eggplants next to onions, garlic, or cereals because thrips often build up to large numbers on these crops. Currently it is not known if thrips are an economic problem in eggplant and treatment for thrips is not recommended.
UC IPM Pest Management Guidelines:
UC ANR Publication 3475
J. L. Aguiar, UC Cooperative Extension, Riverside County
M. J. Jimenez, UC Cooperative Extension, Tulare County
P. B. Goodell, UC IPM, Kearney Agricultural Research and Extension Center, Parlier