Thrips have been collected from 29 plant orders, including various berries, cotton, day lilies, field crops, grass flowers, legumes, peonies, privet hedges, roses, azaleas, rhododendrons, trees, vines, and weeds. They seem to prefer grasses and yellow or light-colored blossoms. Roses are most susceptible in June.
Thrips are very small (1.25-mm or less), fringe winged, and yellowish brown to amber with an orange thorax. The male is slightly smaller and lighter in color than the female.
Plant injury is caused by both nymphs and adults rasping the bud, flower and leaf tissues of the host plants, and then sucking the exuding sap, scraping away the chlorophyll on leaves where they feed. The surface of damaged leaves looks silvery or bronzy. Leaves may be speckled, streaked, spotted or stunted. Flowers may fail to open normally, appearing twisted, discolored, or dried up. Although thrips often hide within flowers or on the undersides of leaves, telltale specks of black excrement reveal their presence. Infestations usually peak during periods of hot, dry weather.
Beneficial insects, like parasitoid wasps, soldier beetles, and the green lacewing, whose larvae hunt and kill the nymphs, are useful. To kill adults on most plants, spray with insecticidal soap, or horticultural oil.