What measures and folk remedies should be used to combat spider mite on cucumbers in a greenhouse? - briefly
Apply cultural, biological, and chemical controls: keep greenhouse humidity above 60 %, spray plants with water to remove mites, release predatory mites (e.g., Phytoseiulus persimilis), and treat foliage with neem oil or insecticidal soap at label rates. For home‑made remedies, use a spray of horticultural oil diluted in water, a garlic‑extract solution, or a potassium bicarbonate mixture, repeating every 5–7 days.
What measures and folk remedies should be used to combat spider mite on cucumbers in a greenhouse? - in detail
Effective control of spider mites on cucumber crops grown in a greenhouse requires an integrated approach that combines cultural practices, biological agents, approved chemicals, and proven home‑made treatments.
Cultural measures reduce mite population pressure. Keep the greenhouse at temperatures between 20 °C and 25 °C; higher temperatures accelerate mite reproduction. Maintain relative humidity around 70 % to discourage development, but avoid excess moisture that promotes fungal diseases. Remove plant debris and weeds that can harbor pests. Rotate crops annually and use resistant cucumber varieties when available. Inspect plants weekly, focusing on the undersides of leaves where mites congregate.
Biological options provide sustained suppression. Release predatory mites such as Phytoseiulus persimilis or Neoseiulus californicus at a rate of 10–20 predators per square meter when early infestations are detected. Ensure adequate pollen or alternative food sources to sustain the predators. Avoid broad‑spectrum insecticides that would eliminate these beneficial organisms.
Chemical interventions, applied only when thresholds are exceeded, include horticultural oils and acaricides registered for greenhouse cucumbers. Apply neem oil at 1 % concentration, covering both leaf surfaces, and repeat every 7–10 days until mite counts fall below economic injury levels. Rotate active ingredients to prevent resistance.
Folk remedies, prepared from readily available materials, can complement the above tactics. Use the following sprays:
- Mild soap solution: Dissolve 1–2 teaspoons of pure liquid soap in 1 liter of water. Spray until runoff; repeat every 5 days during warm periods.
- Garlic‑pepper decoction: Blend 5 cloves of garlic and 1 teaspoon of cayenne pepper with 500 ml of water. Let stand overnight, strain, then dilute with 4 liters of water. Apply every 4–6 days, avoiding direct sun to prevent leaf scorch.
- Baking soda spray: Mix 2 tablespoons of baking soda and 0.5 teaspoon of liquid soap in 1 liter of water. Spray thoroughly; repeat weekly.
- Alcohol‑based rinse: Combine 30 ml of isopropyl alcohol (70 % concentration) with 970 ml of water. Use as a spot treatment on heavily infested leaves; limit to one application per week to avoid phytotoxicity.
All sprays should be applied in the early morning or late afternoon to reduce evaporation and leaf damage. Conduct a small leaf test before full coverage to verify plant tolerance.
Monitoring remains essential. Use a hand lens or sticky traps to count mites; implement control actions when populations exceed 5 mites per leaf. Consistent record‑keeping of temperatures, humidity, and treatment dates helps refine the program and prevents unnecessary chemical use.