How to Manage Pests

UC Pest Management Guidelines

DESCRIPTION OF THE PESTS

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. The most distinctive characteristic of thrips are 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 cereals, onions, garlic, and broadleaved crops.

DAMAGE

The primary damage caused by thrips to peppers is the vectoring of tomato spotted wilt virus. Once the thrips nymphs acquire the virus by feeding on infected plants, they retain the ability to transmit it for the remainder of their lives and it can be passed from one generation of thrips to the next through the eggs.

MANAGEMENT

If possible, avoid planting peppers next to onions, garlic, or cereals because thrips often build up to large numbers on these crops. Also, avoid fields near greenhouses where ornamentals (cut flowers) are grown as these plants serve as hosts for the virus and thrips. Treatment for thrips is not recommended on peppers and is not effective in preventing virus transmission.

PUBLICATION

UC IPM Pest Management Guidelines: Peppers
UC ANR Publication 3460
Insects and Mites
E. T. Natwick, UC Cooperative Extension Imperial County
J. T. Trumble, Entomology, UC Riverside
Acknowledgment for contributions to Insects and Mites:
W. J. Bentley, UC IPM Program, Kearney Agricultural Center, Parlier
R. L. Coviello, UC Cooperative Extension, Fresno County
C. G. Summers, Kearney Agricultural Center, Parlier
W. E. Chaney, UC Cooperative Extension, Monterey County
C. F. Fouche, UC Cooperative Extension, San Joaquin County

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