How to save cucumbers from spider mites in a greenhouse during fruiting in polycarbonate? - briefly
Use a miticide (e.g., abamectin) combined with biological control agents such as Phytoseiulus persimilis, keep leaf surface moisture high by frequent misting, and maintain ventilation to reduce humidity fluctuations. Regularly inspect plants and remove heavily infested leaves to prevent spread.
How to save cucumbers from spider mites in a greenhouse during fruiting in polycarbonate? - in detail
Cucumber plants in a polycarbonate greenhouse are especially vulnerable to spider mite infestations when they begin to bear fruit. Effective control requires a combination of cultural, physical, and chemical measures applied before the pest reaches damaging levels.
Maintain optimal environmental conditions. Keep relative humidity above 60 % by misting or installing humidifiers; high humidity interferes with mite reproduction and reduces their mobility. Regulate temperature within the 22‑28 °C range, avoiding excessive heat that accelerates population growth. Ensure adequate ventilation to prevent stagnant air, which favors mite development.
Implement strict sanitation. Remove plant debris, fallen leaves, and any infested material from the growing area each day. Disinfect tools, benches, and trays with a solution of 0.5 % sodium hypochlorite before reuse. Quarantine newly introduced seedlings for at least two weeks, inspecting them closely for signs of infestation.
Introduce biological antagonists. Release predatory mites such as Phytoseiulus persimilis or Neoseiulus californicus at a rate of 10–15 predators per square meter. Repeat applications every 5–7 days until the pest population declines. Provide a refuge of pollen or yeast to sustain the predators during periods of low prey density.
Apply targeted miticides only when monitoring indicates a population threshold of 5–10 mites per leaf. Use products approved for greenhouse use that contain neem oil, abamectin, or spinosad, rotating active ingredients to prevent resistance. Follow label‑specified dosage and interval; typically, a spray every 7–10 days with a 14‑day withholding period before harvest.
Conduct regular scouting. Examine the undersides of leaves with a 10× hand lens twice weekly, counting mites per leaf and noting the presence of webbing or stippling. Record data in a log to identify trends and determine the precise moment to initiate control actions.
Enhance plant vigor. Apply balanced fertilization with a focus on calcium and potassium, avoiding excessive nitrogen that encourages tender foliage attractive to mites. Mulch the soil surface with organic material to retain moisture and reduce plant stress.
By integrating humidity management, sanitation, biological agents, prudent chemical use, diligent monitoring, and optimal nutrition, cucumber growers can suppress spider mite outbreaks and preserve fruit quality throughout the production cycle in a polycarbonate greenhouse.