How to defeat a spider mite? - briefly
Apply a miticide such as abamectin or neem oil and rinse plants with a strong water spray to remove the pests. Supplement chemical control with predatory mites and keep leaf humidity high to inhibit reproduction.
How to defeat a spider mite? - in detail
Spider mites thrive on warm, dry conditions and reproduce rapidly, so prompt action is essential. Begin with cultural controls: keep humidity above 60 % by misting foliage or using a humidifier, and avoid excessive nitrogen fertilization that creates tender growth. Remove heavily infested leaves and dispose of them away from the garden to reduce the population source.
Biological agents provide effective, chemical‑free suppression. Release predatory mites such as Phytoseiulus persimilis or Neoseiulus californicus at a rate of 1 – 2 m² per week; these predators consume several spider mites per day and establish a self‑sustaining colony. Apply a commercial preparation of Beauveria bassiana, a fungus that infects and kills mites, following label instructions for spray volume and re‑application intervals.
When chemical measures are unavoidable, select miticides with low toxicity to beneficial insects. Recommended options include:
- Abamectin – apply at the lowest effective concentration, repeat after 7 days if needed.
- Spiromesifen – contact spray, effective against all life stages, re‑treat in 10 days.
- Bifenthrin – use only as a last resort; withdraw after treatment to allow predator recovery.
Rotate products with different modes of action to prevent resistance development. Record each application, noting the date, product, and observed mite density, to track effectiveness and adjust the program.
Regular monitoring completes the strategy. Inspect the undersides of leaves weekly with a 10× hand lens; count mites in a defined area (e.g., 5 cm²) and compare against economic thresholds (typically 5–10 mites per leaf). Early detection enables timely intervention before infestations reach damaging levels.