How can spider mites be killed on cucumbers in a greenhouse? - briefly
Apply miticides such as abamectin or spinosad together with horticultural oil sprays, and keep greenhouse humidity low with good ventilation. Introduce predatory mites like Phytoseiulus persimilis and rotate cucumber crops to sustain biological control.
How can spider mites be killed on cucumbers in a greenhouse? - in detail
Effective control of spider mites on cucumber crops cultivated in greenhouse environments requires an integrated approach that combines cultural, biological, and chemical tactics.
Cultural measures reduce mite populations by creating unfavorable conditions. Maintain low humidity (45‑55 %) and moderate temperature (22‑26 °C) to limit reproduction. Remove heavily infested leaves and prune excess foliage to improve air circulation. Implement a strict sanitation routine: clean benches, trays, and tools after each harvest, and discard plant debris that could harbor pests.
Biological agents provide targeted suppression without residue. Release predatory mites such as Phytoseiulus persimilis or Neoseiulus californicus at a rate of 1‑2 predators per square meter; these species consume all life stages of the pest. Apply entomopathogenic fungi (e.g., Beauveria bassiana) as a spray, following label rates, to infect and kill mites on contact. Ensure compatible environmental conditions—adequate humidity (≥70 % for fungal efficacy) and minimal pesticide residues—to preserve the efficacy of these organisms.
Chemical options are reserved for severe outbreaks. Select acaricides with low toxicity to beneficial insects, such as neem oil, spinosad, or abamectin, and rotate modes of action to prevent resistance. Apply according to manufacturer instructions, covering both leaf surfaces thoroughly. Observe pre‑harvest intervals and adhere to maximum application frequencies.
Monitoring is essential for timely intervention. Install sticky traps or use a 10 cm² leaf sample examined under a magnifying lens weekly. Record mite counts and adjust control measures when thresholds (e.g., 5 mites per leaf) are exceeded.
By synchronizing sanitation, environmental regulation, predator releases, and judicious pesticide use, growers can achieve sustained suppression of spider mite infestations on greenhouse cucumbers.