Western flower thrips cause direct damage by feeding on plant leaves and flowers as seen in this photo. Note the long, narrow shaped body of the thrips feeding on this leaf. Western flower thrips possess piercing-sucking mouthparts, and tend to feed on the mesophyll and epidermal cells of leaf tissues. Symptoms of feeding include leaf scarring, distorted growth, sunken tissues on leaf undersides. Flowers and leaves have a characteristic “silvery” appearance.
Black fecal deposits are often present and can be seen here on this petunia leaf. Damage to plant leaves may also occur when females, using their sharp ovipositor, insert eggs into plant tissue.
Note the white scarring on the petunia blossom from thrips feeding.