Red spider mite
Pest Tiny mites that thrive in hot, dry conditions, especially under cover.
What to look for
Fine yellow speckling on leaves, bronzing, and fine silky webbing on the undersides and between stems. The mites are barely visible without a magnifying glass.
When: June to September, or all year in a heated greenhouse.
How to prevent it
- Keep greenhouses damp: wet the floor on hot days and ventilate well.
- Water regularly, as drought-stressed plants suffer worst.
- Clean the greenhouse thoroughly in winter.
How to deal with it
- Introduce the predatory mite Phytoseiulus persimilis as a biological control between March and September.
- Spray leaves, undersides especially, with water to raise humidity.
- Remove badly infested leaves and use soft soap sprays on smaller outbreaks.
Crops it affects
If you choose to use any treatment, use only products approved for UK home gardens, follow the label and avoid spraying open flowers. See all pests and diseases.