Western Flower Thrips

Pest Description

• adults: very tiny, ~ 1/16 inch; elongated and yellowish to dark brown
• fringed wings visible under magnification
• nymphs: smaller and yellowish; wingless

Host Plants, Diet & Damage

• many herbaceous plants and flowers; fruits; vegetables; few ornamentals
  feed on plant sap and pollen
• cause yellow/bronze stippling; cupping; leaf browning and dieback
• may cause premature leaf drop and plant death
• can damage flowers and fruit
• can transmit diseases
• leave tiny black varnish-like fecal spots on leaves

Biology, Life Cycle & Damaging Life Stage

• overwinter as adults in debris around host plants
• adult activity begins in spring around budbreak
• eggs laid inside leaf and bud tissue
• eggs hatch in about 1 week; first two nymph stages (and adults) feed on plant tissue, pollen and nectar
• pre-pupae and pupal stages develop in the soil
• many generations per year; continuous indoors
• immatures and adults are the damaging stages

IPM Recommendations

• Manage plants to improve or maintain health.
• Monitor thrips populations on host plants with a “paper test” or visual inspection.
• Preserve beneficial mites and organisms.
• Apply an insecticide (azadirachtin; horticultural oil; insecticidal soap; neem oil; pyrethroid; spinosyn) when monitoring indicates it is necessary.

For more information, see our Western Flower Thrips fact sheet.