Spider Mites
Pest · Commonly affects: Tomatoes, Beans, Cucumbers, Strawberries, Eggplant, Melons
Spider mites are tiny sap-feeding arachnids in the family Tetranychidae (relatives of spiders and ticks, not true insects), with the two-spotted spider mite being the species home gardeners meet most often. They matter because their numbers can explode within days in hot, dry weather, quietly weakening or killing plants before the damage is traced back to them.
How to identify it
Adults are barely visible specks, often smaller than a grain of ground pepper, ranging from pale green or yellow to orange or reddish and frequently marked with two dark spots. The most reliable clues are fine silken webbing on leaf undersides and across shoot tips, plus a stippled, speckled look on the upper leaf surface where the mites have fed. To confirm, tap a suspect leaf over a sheet of white paper and watch for slow-moving dots, ideally checked with a hand lens.
Damage
Spider mites pierce individual leaf cells and drain their contents, leaving tiny yellow or bronze stipple marks that merge into a dull, dusty, or scorched appearance as feeding builds. Badly infested leaves dry out, curl, and drop early, and heavy pressure can stunt plants and cut yields, hitting drought-stressed and dusty plants hardest.
Prevention
Keep plants vigorous with adequate spacing and good airflow, since crowded, dusty, water-stressed plants are far more prone to outbreaks. Rotate crops, clear out heavily infested plant debris and nearby weeds that shelter mites over the season, and avoid pushing soft growth with excess nitrogen fertilizer, which mites favor. Building healthy soil that holds steady moisture and choosing well-adapted varieties helps plants shrug off light feeding.
How to manage it
A firm spray of plain water aimed at leaf undersides dislodges mites, eggs, and webbing and is one of the most effective non-chemical tools, especially repeated every few days during a flare-up. Prune out and bag the most heavily webbed leaves and shoots to remove egg-laden tissue, and keep plants well watered and free of road or path dust, which discourages buildup. Protect the natural enemies that keep mites in check, including predatory mites, lady beetles, minute pirate bugs, and lacewing larvae, which often bring populations back down on their own.
General guidance for US home gardens, focused on prevention and non-chemical control. For a confirmed diagnosis and options specific to your area, contact your local Cooperative Extension office. Page updated Aug 4, 2026.