The body color of adult onion thrips changes depending on their food, ranging from light–brown to light–yellow with brown–grey colored wings. Both adults and larvae have short antennae. The adult onion thripsranges from 0.8 to 1.2mm. This species is very similar to the western flower thrips (Franklinielaaoccidentalis).

Onion thrips damage and distribution

The onion thrips can be found on all plant parts, but has a preference for young leaves in the middle of the plant. It can usually be found on the underside of the leaves along the large veins. Pupation happens in the soil. The thrips are very active and scatter and hide when disturbed. Adult thrips can fly, which they do, especially when disturbed. They feed by puncturing and sucking leaf cells. Punctured cells will change color and form silver-white spots.  During heavy infestation, leaves will wither and die. In onion, this leads to reduced bulb size. Onion thrips is a known vector of several viruses, including tomato spotted wilt virus.