Plant Problem Diagnostic
Spider Mites in the Garden
The short answer
Two-spotted spider mites are nearly microscopic sap-suckers that pierce leaf cells, causing fine stippling, bleaching, and yellowing, with fine webbing in heavy infestations. They explode in hot, dry conditions, so the first least-toxic steps are to rinse plants with a forceful spray of water and reduce dusty, drought-stressed conditions.
For persistent infestations, least-toxic contact categories such as insecticidal soap or horticultural oil can be used, applied to reach leaf undersides where mites feed. Scout early and often, because populations build fast and are hard to control once webbing and leaf drop appear.
How to identify it
Two-spotted spider mites are tiny (about 1/50 inch), with two dark blotches on a gray-green to yellowish body, found mostly on leaf undersides. Damage shows as stippled, bleached, or yellowing foliage, sometimes with fine silk webbing and premature leaf drop. Tap a leaf over white paper to see moving specks.
- Nearly microscopic mites with two dark spots
- Stippled, bleached, or yellowing leaves
- Fine webbing in heavy infestations
- Worse in hot, dry, dusty conditions
IPM least-toxic management
- 1Scout early — Check leaf undersides regularly and tap leaves over white paper; early detection is essential because mites reproduce quickly.
- 2Rinse plants — Spray plants, including leaf undersides, with a forceful stream of water to knock mites off and raise humidity.
- 3Reduce stress and dust — Keep plants adequately watered and reduce dusty conditions, since dryness and heat favor mite outbreaks.
- 4Use soap or oil if needed — For stubborn infestations, apply a least-toxic contact category such as insecticidal soap or horticultural oil, covering leaf undersides thoroughly.
When to escalate
Spider mites are notoriously hard to control once established, and some can develop resistance. If least-toxic measures fail on a valuable plant, consult your county Extension for miticide guidance, and always follow the label.
Sources
Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.
- Montana State University Urban IPM — Two-Spotted Spider Mite — Two-spotted spider mites are tiny mites with two dark blotches that suck cell contents causing stippling and yellowing; populations increase with dryness and heat and reproduce rapidly.
- University of Delaware Cooperative Extension — Two-spotted Spider Mite — Spider mites cause discolored, stippled foliage and webbing; scouting, water sprays, and least-toxic controls are used, with control challenging due to rapid reproduction.