What brings spider mites onto cucumbers in a greenhouse? - briefly
High temperatures combined with low humidity and dense cucumber foliage create optimal conditions for spider mite colonization, while poor ventilation and the proximity of already infested plants accelerate their spread.
What brings spider mites onto cucumbers in a greenhouse? - in detail
Spider mites become established on cucumber plants in greenhouse production when several ecological and cultural factors converge.
High temperature combined with low relative humidity creates optimal conditions for mite reproduction. Temperatures above 25 °C and humidity below 50 % accelerate egg laying and reduce mortality, allowing populations to expand rapidly.
Plant stress increases susceptibility. Excessive nitrogen fertilization produces lush, tender foliage that attracts mites, while water deficits or irregular irrigation weaken plant defenses and facilitate infestation.
Poor air movement promotes localized microclimates where heat and dryness persist. Stagnant air also hinders the dispersal of natural predators, reducing biological control pressure.
Presence of alternative host species within the greenhouse—such as weeds, weeds in gutters, or neighboring crops—provides a reservoir from which mites can migrate onto cucumbers.
Contamination through infested planting material or equipment introduces mites directly. Use of contaminated seedlings, seed trays, or tools can seed an outbreak even in a previously clean environment.
Broad‑spectrum insecticide applications eliminate predatory insects that normally suppress mite numbers. Residual chemicals may also irritate mites, prompting them to disperse to new foliage.
Summarized factors:
- Warm, dry climate (≥ 25 °C, ≤ 50 % RH)
- Nutrient imbalance, especially high nitrogen
- Water stress or irregular irrigation
- Insufficient ventilation and air circulation
- Adjacent non‑cucumber hosts serving as mite reservoirs
- Introduction via infested seedlings, trays, or tools
- Disruption of natural enemies through indiscriminate pesticide use
Each element contributes to a conducive environment for spider mite colonization on cucumber crops within greenhouse settings. Managing these variables reduces the likelihood of severe infestations.