Plant Problem Diagnosis Key / Pests
Pest
Thrips
Frankliniella occidentalis and others
Slender insects about 1-2 mm long that rasp leaf and petal cells and suck out the contents. Some also spread plant viruses.
Signs
- Silvery or bleached patches with tiny black specks of droppings.
- Streaked or spotted petals, deformed flowers and buds.
- Yellow sticky cards catch the adults.
What favors it
Warm, dry conditions and plenty of flowers, which they hide in. They pupate on leaves, in the soil or in leaf litter, out of reach of most foliar sprays.
Prevention
- Hang yellow sticky cards and count weekly.
- Control weeds around the crop.
- Inspect incoming plants, especially flowering ones.
Often confused with
Sources
- Thrips in Home GardensUniversity of Maryland Extension
- Thrips on Vegetables and FlowersMontana State University Extension
- Thrips Management in GreenhousesUniversity of Maryland Extension
Treatment by crop
Cultural, biological and chemical options in the order to use them, and notes written for each crop.
Identification is free. Treatment is on the Home and Pro plans.
Questions in the key that lead here
- Look the plant over, leaf undersides included. Are insects, mites, slugs, eggs, webbing or droppings on it?
Yes, something living or its traces - What is on the plant?
Specks that are hard to see by eye - What does the damage look like?
Silvery scars with black specks of droppings
Not a match? Start the key or describe what you see.
More photos
More from university Extension: search Extension pages on thrips, or find a plant diagnostic lab through your state's Extension.
Other pests
- Aphids
- Bagworms
- Bark beetles of pine and spruce
- Broad mites and cyclamen mites
- Caterpillars
- Cicada and twig-cutting damage
- Colorado potato beetle
- Cucumber beetles
- Cutworms
- Elm leaf beetle
- Emerald ash borer
- Flea beetles
- Fungus gnats
- Galls on leaves and twigs
- Hemlock woolly adelgid
- Japanese beetles
- Lace bugs
- Leafminers
- Mealybugs
- Pine sawflies
- Root aphids
- Root-knot nematodes
- Russet mites
- Sapsucker damage
- Scale insects
- Shore flies
- Slugs and snails
- Spider mites
- Spongy moth (gypsy moth)
- Spotted lanternfly
- Squash bugs and stink bugs
- Squash vine borer
- Tent caterpillars and fall webworm
- Whiteflies
- Wood borers