How should a greenhouse be treated for mites in spring? - briefly
Begin by thoroughly cleaning the greenhouse, eliminating plant debris, and washing surfaces with a mild detergent or horticultural soap. Then introduce predatory mites as biological control and, if needed, apply an approved acaricide while keeping humidity low and ensuring adequate ventilation.
How should a greenhouse be treated for mites in spring? - in detail
Mite populations rise rapidly as temperatures increase, making early spring the critical period for greenhouse protection. Effective management begins with thorough inspection. Use a hand lens or microscope to examine the undersides of leaves, buds, and stems weekly. Record infestation levels to determine treatment thresholds.
Sanitation reduces habitat and food sources. Remove plant debris, fallen leaves, and infested material. Clean benches, trays, and pots with a detergent solution, then rinse with water. Disinfect tools and equipment with a 10 % bleach solution or a commercial horticultural sanitizer.
Cultural practices limit mite development. Adjust temperature and humidity to the lower end of the crop’s optimal range; many mite species thrive above 25 °C and low humidity. Increase air circulation with fans to disrupt mite movement. Rotate crops and avoid planting the same species in the same location for successive cycles.
Biological agents provide long‑term suppression. Release predatory mites such as Phytoseiulus persimilis, Neoseiulus californicus, or Amblyseius swirskii according to the manufacturer’s rate. Ensure that pesticide residues do not harm the released predators; avoid broad‑spectrum chemicals before and after release.
When chemical intervention is necessary, select products with proven efficacy against spider and broad‑mite species. Apply miticides that contain abamectin, bifenazate, or spirodiclofen, following label rates and pre‑harvest intervals. Rotate active ingredients to prevent resistance; do not repeat the same mode of action more than two consecutive applications.
After treatment, monitor for resurgence. Continue weekly inspections for at least four weeks, adjusting control measures as needed. Maintain detailed records of inspection dates, infestation levels, control actions, and outcomes to refine future spring management plans.