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. |
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| 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. |
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