Contents: By Damage and Image
Thrips are insects in the order Thysanoptera. Western flower thrips, Frankliniella occidentalis, is one of several thrips that can be damaging to ornamental crops. During the summer months when nearby crops are harvested, large migrations of thrips into productions areas can occur. These populations of thrips can be large enough to cause extensive damage to susceptible plants, including terminal losses and stunting. We've had reported damage from azaleas, Amelanchier, cherries, chrysanthemum, crabapple, hawthorn, gerbera, laurel, Norway, red, sugar and Japanese maples, mountain ash, purple leaf plum, and viburnum
Thrips of California 2012 Lucid key is a very robust key with many of thrips that might also occur in the PNW. Best to use if you have a slide mounted specimen.
Western Flower Thrips
The Integrated Plant Protection Center, Oregon State University: Western Flower Thrips has information and phenology useful for Oregon growers.
UC IPM Online Pests in the Landscapes and Gardens: Thrips has some very nice information on monitoring and management.
From UC Riverside - Western Flower Thrips in Greenhouses: A Review of its Biological Control and Other Methods. An absolutely fantastic guide for those interested in biological control.
Pacific Northwest Plant Disease Management Handbook has great information
on managing two key viruses vectored by thrips:
Impatiens -- Impatiens Necrotic Spot; Greenhouse
Plants, Ornamental -- Impatiens Necrotic Spot
Canas, L. 2016. Managing Thrips Resistance to Insecticides. Greenhouse Product News. <2 June 2016>
Cal Ag's article on IPM Works in California Greenhouse Cut Roses discusses thrips management. A PDF with images can be downloaded from the site.
Poinsettia thrips (Echinothrips americanus)
Orginal publication: 8/3/2004
Author: R.L. Rosetta, Extension Nursery Integrated Pest Management, Department of Horticulture, Oregon State University