Thrips

• Silver-gray or bronze streaking and stippling on leaf surfaces
• Distorted, curled, or scarred young leaves and flower petals
• Tiny, slender insects (about 1/20 inch) moving quickly — nearly invisible without magnification
• Black fecal specks on leaf surfaces alongside silver damage
• Ring-spotted leaves if tomato spotted wilt virus is transmitted

Thrips are tiny winged insects that can overwinter on weeds or debris. They develop rapidly in warm weather — a generation can complete in two weeks at 80°F. Females lay eggs inside plant tissue; larvae feed on leaves and flowers before dropping to pupate in the soil. Western flower thrips is a vector of tomato spotted wilt virus (TSWV), making it more significant than its feeding damage alone.

1. 01Inspect flowers and growing tips regularly with a hand lens — thrips hide in flowers and folds
2. 02Remove weeds around the garden that can serve as reservoir hosts
3. 03Blue sticky traps are more effective than yellow for monitoring thrips
4. 04Insecticidal soap or spinosad applied to leaf undersides and flowers can suppress populations
5. 05Reflective mulch (silver plastic) disorients thrips and reduces landing on plants
6. 06Avoid over-fertilizing with nitrogen — lush tender growth attracts thrips

If you're seeing ring spots or necrotic patches on tomato or pepper foliage alongside thrips, tospoviruses like TSWV may be involved. An extension plant pathologist can confirm the diagnosis — there is no cure for infected plants, and knowing the vector is key to prevention next season.

• Thrips in Vegetable Gardens— University of Maryland Extension
• Western Flower Thrips— UC ANR Integrated Pest Management