How can spider mites be controlled on cucumbers in a greenhouse? - briefly
Spider mite infestations on greenhouse cucumber crops can be managed through an integrated approach combining cultural, biological, and chemical tactics. Implement regular scouting, prune heavily infested foliage, release predatory mites (e.g., Phytoseiulus persimilis), and apply miticides only when economic thresholds are reached.
How can spider mites be controlled on cucumbers in a greenhouse? - in detail
Effective management of spider mite infestations on greenhouse cucumbers requires an integrated approach that combines cultural, biological, and chemical tactics.
Maintain optimal environmental conditions to discourage mite reproduction. Keep temperature between 18‑22 °C and relative humidity above 60 %. Adequate ventilation reduces leaf surface dryness, a factor that accelerates mite development. Regularly inspect plants, focusing on the undersides of leaves where mites congregate, and remove heavily infested foliage promptly.
Implement cultural practices that limit pest buildup. Rotate cucumber varieties each season, and avoid planting susceptible cultivars consecutively. Use reflective mulches or aluminum foil strips to repel mites by disrupting their visual cues. Apply a drip‑irrigation schedule that maintains leaf wetness without causing water stress, thereby creating an unfavorable habitat for the pest.
Introduce and conserve natural enemies. Predatory mites such as Phytoseiulus persimilis, Neoseiulus californicus, and Amblyseius swirskii are proven to suppress spider mite populations. Release rates of 1–2 predators per square meter at the first sign of infestation, followed by weekly augmentations, maintain predator pressure. Provide shelter plants (e.g., buckwheat) and avoid broad‑spectrum insecticides that would harm these beneficial organisms.
When thresholds are exceeded, apply targeted miticides with minimal residual activity. Preferred options include:
- Insecticidal soaps (2–3 % fatty acid solution) applied until runoff, repeated every 5–7 days.
- Neem oil formulations (0.5–1 % active ingredient) sprayed until wet, with a 7‑day interval.
- Abamectin (0.5 ppm) or spirodiclofen (0.1 ppm) applied according to label rates, limited to three applications per season.
Rotate chemistries to prevent resistance development and observe pre‑harvest interval (PHI) restrictions. Combine miticide use with predator releases to enhance control efficacy.
Monitor population dynamics using a leaf‑sampling protocol: collect five leaves per block, count mites under a stereomicroscope, and compare numbers to an economic threshold of 5–10 mites per leaf. Adjust management tactics based on these data to avoid unnecessary treatments.
Document all interventions, environmental readings, and pest counts in a greenhouse log. Continuous record‑keeping enables trend analysis, early detection of outbreaks, and refinement of the integrated program over successive cropping cycles.