How can I remove spider mites from a greenhouse? - briefly
Introduce predatory mites or apply a neem‑oil spray while keeping humidity low and cleaning surfaces regularly to suppress spider mite populations. Remove heavily infested foliage and isolate affected plants to prevent further spread.
How can I remove spider mites from a greenhouse? - in detail
Spider mites thrive in warm, dry greenhouse conditions and can quickly damage foliage. Effective eradication requires a combination of monitoring, cultural adjustments, biological agents, and, when necessary, targeted chemicals.
First, inspect plants regularly. Look for tiny, moving specks on the undersides of leaves, stippled discoloration, and fine webbing. Use a hand lens and a sticky trap to confirm presence and estimate population density.
Second, modify the environment to make it less favorable. Increase humidity to 60–70 % by misting or using humidifiers, and lower daytime temperatures by 2–4 °C if possible. Reduce leaf wetness periods by improving ventilation and spacing plants to allow air flow.
Third, apply cultural controls. Remove heavily infested leaves and dispose of them away from the greenhouse. Clean benches, trays, and equipment with a mild detergent solution. Rotate crops and avoid planting susceptible species in the same location year after year.
Fourth, introduce biological predators. Release predatory mites such as Phytoseiulus persimilis, Neoseiulus californicus, or Amblyseius swirskii according to manufacturer recommendations. Maintain a population of these agents by providing pollen or yeast supplements.
Fifth, consider horticultural oils and soaps. Apply a neem oil or insecticidal soap at concentrations of 1–2 % once every 5–7 days, covering both leaf surfaces. Ensure thorough coverage of the undersides where mites reside.
Sixth, use selective acaricides only if other measures fail. Choose products labeled for greenhouse use, such as abamectin or spirotetramat, and follow label rates and re‑entry intervals precisely. Rotate chemicals with different modes of action to prevent resistance.
Seventh, maintain a monitoring schedule. Check sticky traps weekly, record mite counts, and adjust control tactics based on trends. If populations drop below economic thresholds, reduce intervention intensity to preserve beneficial organisms.
By integrating these steps—regular scouting, humidity and temperature management, sanitation, predator releases, oil or soap applications, and judicious chemical use—spider mite outbreaks can be suppressed and greenhouse productivity protected.