How to fight spider mite on eggplants in a greenhouse? - briefly
Apply a miticide such as neem oil or introduce predatory mites, and keep greenhouse humidity above 60 % to suppress spider‑mite development. Regularly scout leaves, prune heavily infested foliage, and maintain clean growing conditions to keep populations below economic thresholds.
How to fight spider mite on eggplants in a greenhouse? - in detail
Spider mites rapidly colonize eggplant foliage in protected environments, causing stippling, leaf bronzing, and reduced fruit set. Early detection and prompt action are essential to prevent population explosions.
Identify infestations by inspecting the underside of leaves for tiny moving dots and fine webbing. Use a magnifying lens or a handheld microscope to confirm presence. Record infestation levels at least twice weekly during the warmest months.
Implement cultural measures to create an unfavorable habitat:
- Maintain relative humidity above 60 % by misting or using humidifiers; mites thrive in dry air.
- Keep temperatures between 18–24 °C; excessive heat accelerates reproduction.
- Space plants to allow good air circulation, reducing leaf microclimates where mites hide.
- Remove heavily infested leaves promptly, disposing of them away from the greenhouse.
Apply physical controls when populations are low:
- Spray plants with a strong jet of water to dislodge mites from leaf surfaces.
- Use reflective mulches or aluminum foil strips to deter settlement by disrupting visual cues.
When cultural and physical tactics are insufficient, introduce selective chemicals:
- Apply insecticidal soap or neem oil at concentrations recommended by the manufacturer, covering both leaf surfaces.
- Reserve synthetic miticides (e.g., abamectin, spiromesifen) for severe outbreaks; rotate modes of action to delay resistance.
- Observe pre‑harvest intervals and re‑entry periods to ensure crop safety.
Incorporate biological agents for sustainable control:
- Release predatory mites such as Phytoseiulus persimilis or Neoseiulus californicus at rates of 10–20 predators per square meter.
- Augment with entomopathogenic fungi (e.g., Beauveria bassiana) applied as a foliar spray.
- Provide alternative food sources (e.g., pollen) to sustain predator populations between releases.
Adopt an integrated pest management cycle:
- Monitor weekly, record mite counts.
- If counts exceed 5 mites per leaf, initiate water spray.
- If counts remain above threshold after two sprays, apply botanical spray.
- Introduce predatory mites when botanical control shows limited effect.
- Reserve synthetic miticide for counts surpassing 20 mites per leaf despite previous steps.
Document each intervention, adjust timing based on environmental readings, and repeat the cycle throughout the growing season to keep spider mite populations below economic damage levels.