In a cucumber greenhouse with spider mites, what should you do? - briefly
Identify the infestation, isolate the affected plants, and increase greenhouse humidity to suppress mite reproduction. Apply an appropriate miticide or introduce predatory mites (e.g., Phytoseiulus persimilis) and conduct regular scouting to ensure control.
In a cucumber greenhouse with spider mites, what should you do? - in detail
Spider mites can rapidly damage cucumber plants in a greenhouse, so immediate and systematic intervention is required. Begin by confirming the presence of the pest: look for tiny moving specks on leaf undersides, fine webbing, and stippled yellowing of foliage. Use a hand lens or magnifying glass to differentiate spider mites from other insects.
Immediate steps
- Isolate the most heavily infested trays or benches to prevent spread.
- Remove heavily damaged leaves and dispose of them away from the growing area.
- Increase air circulation by adjusting fans and opening ventilation vents; higher air movement reduces mite reproduction.
Cultural tactics
- Lower relative humidity to 50‑60 % and maintain temperatures between 20‑25 °C; spider mites thrive in dry, warm conditions.
- Apply a water spray to the undersides of leaves for 2‑3 minutes, 2‑3 times daily for a week, to dislodge mites and their eggs.
- Rotate crops annually and avoid planting cucumbers in the same location for more than two consecutive seasons.
Biological options
- Release predatory mites (e.g., Phytoseiulus persimilis or Neoseiulus californicus) at a rate of 10–15 predators per square meter; repeat releases every 7‑10 days until mite populations decline.
- Introduce entomopathogenic fungi such as Beauveria bassiana according to label instructions; apply as a foliar spray during cooler parts of the day.
Chemical measures
- If biological control is insufficient, use a miticide with low residual activity, such as abamectin or spirodiclofen, respecting pre‑harvest intervals and rotating modes of action to avoid resistance.
- Apply the product as a fine spray covering both leaf surfaces; repeat at 7‑10 day intervals, monitoring mite counts after each application.
Monitoring and documentation
- Install sticky traps on each bench and inspect them weekly; record mite counts to assess control efficacy.
- Maintain a log of all interventions, dates, and dosages; adjust the program based on observed trends.
By integrating sanitation, environmental adjustment, biological agents, and, when necessary, targeted chemicals, a cucumber greenhouse can suppress spider mite outbreaks and protect crop yield. Continuous monitoring ensures early detection and prevents re‑infestation.