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IPM Scouting in Stone Fruits

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Western flower thrips - Frankliniella occidentalis (Pergande)
IPM scouting in stone fruits > Western flower thrips
Western flower thrips (WFT) are a pest of various stone fruit. They overwinter as adults in the orchard floor or in nearby weedy habitat. Early-season feeding under the shuck by adults and nymphs scars the fruit surface. The scars expand as the fruit grows. Direct feeding on maturing fruit causes blemishes, referred to as silvering, which can downgrade the fruit. Thrips will also feed within flowers around bloom time.

Monitoring: Adults and nymphs can be detected at bloom by dissecting flowers, or by jarring WFT from the flower. WFT move quickly when disturbed. California Extension guidelines recommend treatment if adults infest more than 10% of 50 blossoms from 10 to 12 trees, or if nymphs are present. Inspect ripening fruit for silvering.
Western flower thrips WFT are slender and yellowish. Adults are about 1.5 mm long and have fringed wings that are folded over their backs. Immatures are similar in appearance, although lighter in color and wingless.
Additional information
This information was developed from A Pocket Guide for IPM Scouting in Stone Fruits by David Epstein, Larry J. Gut, Alan L. Jones and Kimberly Maxson-Stein. Purchase this in a pocket-sized guide for reference in the orchard from MSU Extension (publication E-2840).
The MSU IPM Program maintains this site as an access point to pest management information at MSU. The IPM Program is administered within the Department of Entomology, fueled by research from the Michigan Agricultural Experiment Station, delivered to citizens through MSU Extension, and proud to be a part of Project GREEEN.
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Updated 7/24/07