There are many different species of thrips (over 6,000). In general, thrips are not host plant specific and have a wide range of host plants.
Thrips are common pests of greenhouse plants and crops: Greenhouse thrips (Heliothrips haemorroidalis), Banded greenhouse thrips (Hercinothrips femoralis), Flower thrips (Frankliniella tritici), Western flower thrips (Frankliniella occidentalis), and Onion or tobacco thrips (Thrips tabaci).
These slender insects are usually less than 1/8" long and feed primarily on young tissue in the bud or on newly expanded leaves by sucking up sap after chewing through surface cells with their mouthparts. Injured leaves and stems dry out giving a whitish or silver-flecked appearance.
Our wide variety of beneficial organisms will eliminate most species of thrips.
Photos courtesy of: Alton N. Sparks, Jr., University of Georgia and Whitney Cranshaw, Colorado State University, Bugwood.org