How to treat soil in a greenhouse against mites? - briefly
Apply a soil drench of neem oil or a registered miticide, then introduce beneficial nematodes to reduce mite numbers. Maintain sterile substrate, clean greenhouse practices, and lower humidity to prevent re‑infestation.
How to treat soil in a greenhouse against mites? - in detail
Effective management of greenhouse soil to suppress mite populations requires a systematic approach that combines sanitation, cultural practices, biological agents, and, when necessary, targeted chemical interventions.
First, eliminate existing infestations by removing plant debris, old media, and any organic matter that can harbor mites. Replace the soil with a sterile substrate or treat the existing medium with a heat‑based sterilization cycle (70 °C for 30 minutes) to eradicate eggs and juveniles. After sterilization, allow the soil to dry to a moisture level of 40‑50 % before re‑planting, as overly moist conditions favor mite reproduction.
Cultural strategies include:
- Rotating crops every 3–4 weeks with non‑host species to break the life cycle.
- Applying a thin layer (2‑3 cm) of coarse sand or diatomaceous earth on the soil surface; this creates a hostile environment for crawling stages.
- Maintaining proper ventilation to keep relative humidity below 70 %, reducing the microclimate that supports mite development.
- Implementing a strict sanitation protocol: disinfect tools, benches, and footwear with a 5 % bleach solution or an approved horticultural disinfectant after each use.
Biological control options are:
- Introducing predatory mites such as Phytoseiulus persimilis or Neoseiulus californicus; release rates of 10–20 individuals per square meter provide rapid suppression.
- Applying entomopathogenic fungi (e.g., Beauveria bassiana) as a soil drench; follow label instructions for concentration and repeat applications every 7 days during peak activity.
When chemical measures become unavoidable, select products with low phytotoxicity and short residual activity. Soil‑active acaricides containing abamectin or spinosad can be applied as a drench at the recommended rate, followed by a 14‑day interval before harvesting. Rotate active ingredients to prevent resistance development.
Continuous monitoring is essential. Use sticky traps placed at soil level and conduct weekly inspections of leaf litter and root zones. Record mite counts and adjust management tactics accordingly.
By integrating sanitation, environmental control, biological agents, and judicious chemical use, growers can maintain a mite‑free substrate, ensuring healthy plant growth and optimal greenhouse productivity.