Western flower thrips and flower thrips
Frankliniella occidentalis (Pergande)
Frankliniella tritici (Fitch)
Western flower thrips [Frankliniella occidentalis (Pergande)] and Flower thrips [Frankliniella tritici (Fitch)] are indistinguishable without a microscope. Adults are slender and yellowish, with short antennae; the wings are long and narrow, and held over the abdomen (A). Larvae are smaller and wingless, but otherwise resemble adults.
QC, NY and PA, and south through the mid-Atlantic states.
Both species attack nectarine and other stone fruits. Adults infest developing fruit during bloom and again as the fruit ripens. Larval and adult feeding at bloom through shuck fall causes scars on the fruit surface that expand as the fruit grows (B). Feeding near harvest can result in a silvering or russetting of the fruit surface (C). High thrips infestations feeding on terminal growth can cause distortion of leaves and excess branching.
Injury tends to be more severe in orchards located in proximity to greenhouses, and under drought conditions. Insecticide sprays may be necessary at petal fall and close to harvest.
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 AgBioResearch, delivered to citizens through MSU Extension, and proud to be a part of Project GREEEN.