Plant Problem Diagnosis Key / Pests
Russet mites
Aculops spp. (tomato russet mite, hemp russet mite)
Tiny, conical mites that feed on stems and leaf surfaces. They spread from the bottom of the plant upward, and on tomato they can kill a plant in a few weeks.
Signs
- Lower stems and leaves turn greasy bronze or russet.
- Lower leaves dry out as the mites move up the plant.
- Under a 14x lens or stronger: masses of yellowish, conical mites on the green leaves above the damage.
What favors it
Greenhouse crops, where they survive year-round; spread on wind and by people moving between plants.
Prevention
- Check lower stems and leaves with a 14x lens weekly in summer.
- Remove infested plants and volunteer tomatoes and nightshade weeds.
- Clean stakes, clips and tools between crops.
Crops it shows up on
Tomato, pepper & eggplant; Hemp & cannabis.
Often confused with
Sources
- Hemp Russet Mite in Industrial HempNC State Extension
- Tomato Russet MiteUC Statewide IPM Program
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?
Twisted, shiny or bronzed growth, no webbing - Where did it start?
Low on the plant, moving upward
Not a match? Start the key or describe what you see.
More photos
More from university Extension: search Extension pages on russet mites, 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
- 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
- Thrips
- Whiteflies
- Wood borers