How to treat a spider mite infestation? - briefly
Apply a miticide or horticultural oil and prune heavily infested leaves, keeping humidity low and watering consistently to disrupt the mites’ life cycle. Introduce predatory agents such as Phytoseiulus persimilis for biological control.
How to treat a spider mite infestation? - in detail
Spider mites thrive in warm, dry conditions and can quickly defoliate indoor and outdoor plants. Effective control requires a combination of cultural, mechanical, biological, and chemical measures applied systematically.
First, reduce the environment that favors reproduction. Lower ambient temperature to 70 °F (21 °C) or below, increase relative humidity to 60 % or higher, and eliminate dust that protects the mites. Prune heavily infested foliage, discarding it in sealed bags to prevent spread.
Second, employ direct removal techniques. Spray plants with a strong jet of water to dislodge mites from leaves; repeat every 2–3 days until populations decline. For indoor crops, use a fine‑mist sprayer to ensure thorough coverage of the undersides of leaves, where most mites reside.
Third, introduce natural enemies. Predatory mites such as Phytoseiulus persimilis, Neoseiulus californicus, or Amblyseius swirskii can suppress infestations when released at a rate of 10–20 predators per square foot. Maintain a habitat that supports these agents by providing pollen or yeast supplements.
Fourth, apply miticidal substances only when biological control proves insufficient. Choose products with low mammalian toxicity and short residual activity, such as neem oil, insecticidal soap, or abamectin. Follow label directions precisely: apply in the early morning or late evening, cover both leaf surfaces, and repeat every 5–7 days for three to four applications.
Fifth, monitor progress. Inspect plants twice weekly using a 10× hand lens; count mites on five random leaf sections and record numbers. If counts fall below five mites per leaf segment for two consecutive inspections, cease treatments but continue preventive cultural practices.
Summary of steps
- Adjust temperature, humidity, and sanitation.
- Dislodge mites with vigorous water sprays.
- Release predatory mite species appropriate to the crop.
- Use targeted miticides if needed, adhering to label instructions.
- Conduct regular scouting and record keeping.
Consistent implementation of these actions eliminates spider mite populations while minimizing chemical exposure and preserving beneficial organisms.