Spider Mite

• Stippled, bronze, or silvery appearance on leaves — tiny pale dots from feeding punctures
• Fine webbing on leaf undersides and between stems, especially in dry weather
• Leaves yellow, dry out, and drop prematurely
• Tiny moving dots visible on the underside of leaves with a hand lens
• Damage worsens rapidly in hot, dry conditions

Spider mites are arachnids, not insects. They thrive in hot, dry conditions and can complete a generation in seven to ten days when temperatures exceed 85°F. Populations can explode rapidly. They overwinter as eggs on bark, plant debris, and perennial weeds. Drought stress and dusty conditions both exacerbate outbreaks. Natural predators — predatory mites, minute pirate bugs — can keep populations in check when broad-spectrum insecticides are avoided.

1. 01Spray leaf undersides forcefully with water every two to three days — this physically removes mites and reduces populations
2. 02Maintain consistent soil moisture — stressed plants are far more vulnerable
3. 03Apply insecticidal soap or neem oil to leaf undersides, where mites live and feed
4. 04Avoid overhead watering that leaves foliage dry by midday; mites prefer dry surfaces
5. 05Preserve natural predators: avoid pyrethroid insecticides, which kill predatory mites
6. 06Horticultural oil can smother eggs and mites — apply when temperatures are below 90°F to avoid phytotoxicity

If populations keep surging despite water blasting and soap applications, an extension office can confirm the species and advise whether predatory mites (like Phytoseiulus persimilis) would be a practical introduction for your situation.

• Spider Mites on Vegetables— University of Maryland Extension
• Twospotted Spider Mite— UC ANR Integrated Pest Management