What should I do if spider mite appears on cucumbers in the open field, and how can I use ammonia spirit? - briefly
Inspect cucumber plants, prune heavily infested leaves, and spray the foliage with a diluted ammonia solution («0.5%–1% NH₃») covering both sides to suppress spider mites. If needed, follow with a mild soap or neem‑oil spray and reduce nitrogen fertilization.
What should I do if spider mite appears on cucumbers in the open field, and how can I use ammonia spirit? - in detail
Spider mites appear as tiny specks on the undersides of cucumber leaves; stippling, yellowing, and webbing confirm infestation. Immediate action prevents rapid population growth.
- Inspect plants every 3–5 days, focusing on leaf margins.
- Remove heavily damaged foliage to reduce mite habitat.
- Increase irrigation frequency to create a humid micro‑environment that discourages mite development.
Biological agents provide sustainable suppression. Predatory mites such as Phytoseiulus persimilis and Neoseiulus californicus are released at a rate of 1 × 10⁴ individuals per hectare. Maintain temperatures above 20 °C to ensure predator activity. Encourage native arthropods by planting flowering strips of dill, coriander, or alyssum.
When cultural and biological measures prove insufficient, a diluted ammonia solution may be employed. Prepare the mixture as follows:
- Combine 10 ml of 25 % aqueous ammonia (ammonia spirit) with 1 liter of water, achieving a 0.25 % concentration.
- Add a non‑ionic surfactant (0.1 % v/v) to improve leaf coverage.
- Apply during early morning or late afternoon to avoid phytotoxicity, ensuring thorough wetting of leaf undersides.
- Repeat applications at 7‑day intervals, limiting total treatments to three per growing season to prevent crop injury.
Safety precautions include wearing gloves, goggles, and protective clothing; avoid contact with skin and eyes. Do not apply on stressed or wilted plants, as ammonia may exacerbate damage. After treatment, monitor mite populations for at least 14 days to assess efficacy.
Integrating regular scouting, habitat manipulation, biological control agents, and calibrated ammonia applications constitutes an effective, low‑risk strategy for managing spider mites on field‑grown cucumbers. Continuous observation and timely intervention sustain yield quality and reduce reliance on broad‑spectrum pesticides.