How to disinfect a polycarbonate greenhouse in autumn from spider mites? - briefly
Clean the greenhouse with a high‑pressure water rinse, then treat all plant material and interior surfaces with a horticultural oil or neem‑oil spray to eradicate spider mites, ensuring complete coverage. Finish by wiping the polycarbonate panels and frame with a 1 % sodium hypochlorite solution, rinse thoroughly, and let dry before use.
How to disinfect a polycarbonate greenhouse in autumn from spider mites? - in detail
Cleaning a polycarbonate greenhouse in the fall to eliminate spider mites requires a systematic approach that combines mechanical removal, chemical treatment, and preventive measures.
Begin by removing all plant material, debris, and soil that could harbor mites. Dispose of infested organic matter in sealed bags to prevent re‑infestation. Sweep the floor and wipe the benches with a stiff brush to dislodge any remaining insects.
Next, wash the entire structure with a high‑pressure water hose. Use a nozzle that provides at least 1500 psi to reach the interior surfaces and the underside of the panels. Follow the rinse with a detergent solution (non‑ionic, pH 7 ± 0.5) at a concentration of 0.5 % by volume. Apply the solution with a sprayer, ensuring thorough coverage of frames, vents, and joints. Rinse again with clean water to remove residue.
After the mechanical cleaning, apply a miticide approved for greenhouse use. Choose a product containing abamectin, spinosad, or bifenthrin, respecting the label dosage (typically 0.5–1 ml L⁻¹). Spray the interior surfaces, paying special attention to cracks, seams, and the undersides of polycarbonate sheets where mites tend to hide. Allow the treatment to dry completely, usually 2–3 hours, before re‑entering the greenhouse.
For an additional safety layer, introduce a biological control agent such as Phytoseiulus persimilis or Neoseiulus californicus. Release 1–2 adult predators per square meter, distributing them evenly across the structure. These predatory mites will consume any surviving spider mites and reduce the risk of a resurgence.
Seal any openings that could allow external mite entry. Install fine mesh screens on ventilation openings, and verify that door seals are intact. Reduce humidity to 50–60 % by adjusting ventilation, as lower moisture levels inhibit mite reproduction.
Finally, schedule a follow‑up inspection 7–10 days after treatment. Use a hand lens to examine leaf undersides and structural surfaces. If live mites are detected, repeat the miticide application at the same dosage, but do not exceed three applications per season to avoid resistance buildup.
By adhering to this protocol—mechanical cleaning, detergent wash, targeted miticide, biological augmentation, and environmental control—the greenhouse will be effectively disinfected of spider mites before winter conditions set in.