How can I control the red spider mite? - briefly
Apply horticultural oil or a neem‑based spray early in the infestation, covering leaf undersides and repeating weekly. Introduce predatory mites such as Phytoseiulus persimilis and keep humidity low with good ventilation to suppress population growth.
How can I control the red spider mite? - in detail
Red spider mites thrive on warm, dry conditions and reproduce quickly; a single female can lay up to 200 eggs in a week. Their feeding punctures plant cells, causing stippling, yellowing, and eventual leaf drop. Early detection relies on inspecting the undersides of leaves for tiny moving specks and fine webbing.
Cultural measures reduce population pressure. Maintain humidity above 60 % by misting foliage or using a humidifier; high moisture disrupts mite development. Remove heavily infested leaves and prune overcrowded branches to improve air circulation. Avoid excessive nitrogen fertilization, which promotes lush growth favored by the pest. Rotate crops and plant resistant varieties when available.
Biological agents provide targeted suppression. Predatory mites such as Phytoseiulus persimilis and Neoseiulus californicus consume all life stages of the red spider mite. Release rates of 50–100 predators per square foot establish effective control within a week. Fungal pathogens like Beauveria bassiana infect mites on contact; apply as a spray following label directions.
Chemical options include acaricides with distinct modes of action. Rotate products to prevent resistance:
- Abamectin (nerve‑targeting, low residual activity) – apply when monitoring shows >5 % infestation.
- Spiromesifen (growth inhibitor) – effective against eggs and nymphs, use early in the season.
- Sulfur dusts – contact killer, best applied in cool evenings to avoid phytotoxicity.
Always adhere to pre‑harvest intervals and personal protective equipment requirements.
Monitoring continues throughout the growing period. Use a hand lens or sticky traps to count mites weekly; threshold levels of 2–3 mites per leaf indicate the need for intervention. Record observations to adjust cultural, biological, and chemical tactics accordingly.