Western flower thrips
Frankliniella occidentalis
46 host plants
Last updated
Western flower thrips are slender insects one-sixteenth inch long, pale tan or yellow, found feeding inside flowers and on developing fruit. Look for silver-white streaking and dark excrement spots on flower petals and developing fruit. Females pierce fruit with their ovipositors to lay eggs, creating sunken brown pits called pansy spots. Damage becomes visible on fruit as it develops.
Scout flowers and developing fruit during petal-fall to 5-millimeter fruit size window. Spray insecticidal soap, spinosad, or pyrethrin-based products just before petal fall. For edible fruit, time applications to avoid harvest restrictions. Encourage predatory mites and parasitic wasps through habitat management and reduced pesticide use.
Quick Reference
Adult thrips are small (about 1 to 2 mm long at maturity), slender insects with fringed wings. They are generally white when young but pale yellow to brown when mature. Larvae are very tiny and difficult to distinguish without magnification. They feed by puncturing plant material, often blossoms, and sucking out the cell contents. Injured blossoms often turn into distorted fruit. When feeding on flowers, affected petals appear stippled or are scarred with brown streaks or spots. When unusually...
Cultural Controls
- There are no significant natural controls early in the season when damage is occurring.
- Later in the year, predators such as lacewings and minute pirate bugs may reduce populations.
- Cold, wet weather during bloom also reduces thrips damage.
- Fields adjacent to unmanaged or wild land that contains many flowering host plants are often subject to more damage because of the habitat such areas offer.
- If other flowering plants with desirable flowers...