How to treat a polycarbonate greenhouse against spider mites? - briefly
Apply a targeted miticide spray approved for polycarbonate structures, following label rates and ensuring thorough coverage of leaves and undersides, then repeat the treatment after 7‑10 days to break the mite life cycle. Maintain low humidity and introduce predatory mites to prevent future infestations.
How to treat a polycarbonate greenhouse against spider mites? - in detail
Spider mites thrive in warm, dry conditions typical of polycarbonate structures. Early detection prevents rapid population growth. Inspect leaves twice weekly, focusing on the undersides for tiny moving specks and fine webbing. Use a hand lens to confirm presence.
Control measures combine cultural, physical, biological, and chemical tactics.
- Reduce humidity levels by opening vents and using fans to increase air flow. Aim for relative humidity above 60 % when possible.
- Lower temperature extremes by shading the greenhouse during peak sunlight hours. Install reflective screens or shade cloths to keep leaf surface temperatures below 30 °C.
- Remove heavily infested foliage promptly. Dispose of plant material in sealed bags to avoid spreading mites.
- Wash plants with a strong jet of water, targeting the leaf undersides. Repeat every 5–7 days during an outbreak.
- Apply insecticidal soap or neem oil at the label‑recommended concentration. Cover all plant surfaces; reapply after rain or irrigation.
- Introduce predatory mites (Phytoseiulus persimilis, Neoseiulus californicus) once populations exceed 5 mites per leaf. Maintain a refuge of pollen or yeast to sustain predators.
- Use horticultural oil sprays for severe infestations, ensuring thorough coverage and allowing a 24‑hour interval before applying any other pesticide.
Monitoring continues after treatment. Record mite counts on a simple chart to assess decline. If numbers rise despite interventions, rotate to a different miticide class to prevent resistance. Maintain cleanliness by cleaning polycarbonate panels with a mild detergent, removing dust that can shelter mites.
Integrating these steps provides sustained protection against spider mite damage in polycarbonate greenhouse environments.