How to treat cucumbers in a greenhouse against diseases caused by mites? - briefly
Use a miticide program that combines systemic acaricides (e.g., abamectin) with botanical oils (e.g., neem), applied at label‑recommended intervals while keeping humidity low, ventilation high, and removing infested leaves promptly. Complement chemical control with biological agents such as predatory phytoseiid mites and regular monitoring using sticky cards to suppress mite‑borne diseases.
How to treat cucumbers in a greenhouse against diseases caused by mites? - in detail
Effective management of cucumber production in protected cultivation against mite‑borne diseases requires an integrated approach that combines monitoring, cultural adjustments, biological agents, and, when necessary, targeted chemicals.
Accurate diagnosis is the first step. Typical symptoms include stippled leaf surfaces, yellowing, and webbing on the undersides of leaves. Microscopic examination confirms the presence of two‑spotted spider mites (Tetranychus urticae) or other phytoseiid species. Early detection prevents rapid colony expansion.
Preventive measures focus on creating unfavorable conditions for mite development. Maintain relative humidity between 70 % and 80 % and keep temperature within the optimal range of 22 °C to 26 °C; both factors reduce mite reproduction rates. Ensure adequate air circulation with fans or vent openings to avoid stagnant microclimates. Implement strict sanitation: remove plant debris, disinfect tools, and isolate new seedlings for a minimum of two weeks before introduction.
Cultural practices that limit host availability include:
- Rotating cucumber varieties with those displaying documented resistance to mite‑transmitted viruses.
- Pruning excessively dense foliage to improve light penetration and reduce humid micro‑environments.
- Applying mulches that reflect excess heat, thereby lowering leaf temperature.
Biological control agents provide sustainable suppression. Commercially available predatory mites such as Phytoseiulus persimilis, Neoseiulus californicus, and Amblyseius swirskii establish quickly on cucumber foliage and consume large numbers of spider mites. Release rates of 10–20 predatory mites per square meter, repeated weekly for three weeks, achieve effective population reduction. Supplementary entomopathogenic fungi (e.g., Beauveria bassiana) can be sprayed at 1 × 10⁸ conidia L⁻¹ during peak humidity periods.
Chemical interventions are reserved for severe infestations that exceed economic thresholds (typically five mites per leaf). Selective acaricides with low toxicity to predatory mites—such as abamectin, spirodiclofen, or bifenazate—should be applied according to label rates. Rotate active ingredients every 10–14 days to delay resistance development. Avoid broad‑spectrum insecticides that disrupt biological control agents.
Monitoring protocols involve weekly leaf inspections using a hand lens (10× magnification). Record mite counts per leaf and adjust control measures when thresholds are reached. Digital image analysis tools can automate population assessments, providing real‑time data for decision‑making.
Record‑keeping of all interventions, environmental parameters, and pest counts enables trend analysis and continuous improvement of the management program.