How to combat spider mites on garlic? - briefly
Apply a strong jet of water to knock mites off foliage, then treat with neem oil or horticultural oil at weekly intervals, supplementing with insecticidal soap if needed. Keep humidity low, prune damaged leaves, and limit nitrogen fertilization to discourage further infestations.
How to combat spider mites on garlic? - in detail
Spider mites are a common pest of garlic, causing leaf stippling, webbing, and reduced bulb quality. Effective management requires accurate identification, regular scouting, and a combination of cultural, biological, and chemical tactics.
Identify the pest by looking for tiny, moving specks on the undersides of leaves, fine webbing, and yellowing foliage. Use a magnifying lens to confirm the presence of the mite’s oval bodies and eight legs.
Implement cultural practices that reduce mite populations:
- Plant garlic in well‑drained, sunny soil; high temperatures and humidity discourage mite development.
- Space rows 12–15 inches apart to improve air circulation and leaf drying.
- Rotate crops; avoid planting garlic after previous hosts such as onions, leeks, or brassicas.
- Remove weeds and volunteer plants that can harbor mites.
- Apply a mulch layer of straw or shredded leaves to keep the soil cool and suppress weed growth.
Monitor the crop weekly. Count mites on ten random leaf sections; if the average exceeds five mites per leaf, initiate control measures.
Biological options include:
- Predatory insects such as Phytoseiulus persimilis and Amblyseius swirskii; release rates of 10–15 predators per square meter are effective.
- Entomopathogenic fungi like Beauveria bassiana; apply at 1 × 10¹² conidia per hectare, following label instructions.
- Neem oil (5 % azadirachtin) applied as a foliar spray at 2 ml per liter of water; repeat every 7–10 days during active mite periods.
When chemical intervention is necessary, select products with low toxicity to beneficial organisms:
- Abamectin, 0.5 % formulation, sprayed at 0.5 ml per liter; observe a 24‑hour pre‑harvest interval.
- Spiromesifen, 0.4 % solution, applied at 0.4 ml per liter; rotate with other chemistries to avoid resistance.
- Sulfur dust, 1 kg per hectare, applied in the early morning or late afternoon to minimize plant injury.
Integrate all tactics in a stepwise program:
- Begin with sanitation and proper spacing at planting.
- Conduct weekly inspections; record mite counts.
- If thresholds are met, release predatory mites or apply neem oil.
- Escalate to abamectin or spiromesifen if populations persist after two applications of biological agents.
- Conclude with a final sulfur dusting before harvest to eliminate residual mites.
Maintain records of each action, including dates, rates, and observed outcomes, to refine future management cycles. This systematic approach minimizes damage, preserves bulb quality, and reduces reliance on synthetic chemicals.