How to kill spider mites on tomatoes? - briefly
Apply a miticide—neem oil, insecticidal soap, or a licensed acaricide—directly to all leaf surfaces, especially undersides, and repeat every 5–7 days until the population collapses. For sustainable control, release predatory mites such as Phytoseiulus persimilis to consume the pests.
How to kill spider mites on tomatoes? - in detail
Spider mites are tiny arachnids that feed on tomato foliage, causing stippling, yellowing, and leaf drop. Early detection relies on examining the undersides of leaves with a magnifying lens; the presence of fine webbing confirms infestation.
Cultural practices reduce population growth. Space plants 18–24 inches apart to improve air circulation. Water the canopy thoroughly once a week, especially during hot, dry periods, to disrupt mite life cycles. Remove and destroy heavily damaged leaves to eliminate breeding sites.
Mechanical methods provide immediate reduction. Spray foliage with a strong jet of water to dislodge mites; repeat every two days for one week. Prune affected branches and discard them away from the garden.
Chemical options include contact insecticides and systemic products. Apply a horticultural oil (e.g., neem or mineral oil) at a rate of 2 fl oz per gallon of water, covering both leaf surfaces. For severe outbreaks, use a synthetic acaricide such as abamectin, following label instructions for dosage and pre‑harvest interval. Rotate chemicals with different modes of action to prevent resistance.
Biological controls target mites without harming beneficial insects. Release predatory mites (Phytoseiulus persimilis or Neoseiulus californicus) at a rate of 1 million per acre, distributing them evenly over the canopy. Maintain a habitat of flowering herbs (e.g., dill, fennel) to support natural enemies.
Monitoring continues throughout the growing season. Inspect plants weekly, record mite counts, and adjust management tactics when thresholds exceed 5 mites per leaf. Consistent vigilance prevents population spikes and protects tomato yields.