How to combat mites on eggplants in a greenhouse? - briefly
Use cultural practices—prune damaged foliage, keep humidity below 70 % and ensure good air circulation—combined with selective miticides (e.g., abamectin) applied at label‑recommended intervals. Introduce predatory mites such as Phytoseiulus persimilis and monitor infestations regularly with sticky traps.
How to combat mites on eggplants in a greenhouse? - in detail
Mite infestations on greenhouse‑grown eggplant develop quickly under warm, dry conditions. Early detection relies on inspecting leaf undersides with a magnifying lens for tiny, moving specks and for stippled or bronzed leaf tissue. When populations exceed the economic threshold—approximately two mites per leaf tip—intervention becomes necessary.
Cultural measures reduce mite pressure. Maintain relative humidity between 70 % and 80 % by using misting systems or humidifiers; high humidity interferes with mite reproduction. Keep temperatures below 30 °C during the hottest part of the day by shading or ventilation. Remove plant debris and replace old grow‑media to eliminate shelter. Rotate crops with non‑host species for at least one season to break the life cycle.
Mechanical actions provide immediate reduction. Spray foliage with a strong jet of water to dislodge mites, repeating every 3–4 days until counts drop. Install fine mesh screens on vents to prevent entry of airborne mites. Prune heavily infested leaves and discard them in sealed bags.
Biological agents offer sustainable control. Apply predatory mites such as Phytoseiulus persimilis or Neoseiulus californicus at a rate of 1 × 10⁵ individuals per square meter. Release them weekly for three weeks, then maintain a maintenance population by providing a small amount of pollen or a commercial factitious prey. Introduce entomopathogenic fungi (e.g., Beauveria bassiana) as a foliar spray at 1 × 10¹² conidia per liter; repeat at 7‑day intervals.
Chemical options act as a last resort. Use acaricides labeled for cucumber or tomato crops that are also effective on eggplant, applying the lowest effective dose according to the label. Rotate active ingredients to avoid resistance: start with a pyrethroid, follow with a sulfur‑based product, then a neem‑derived formulation. Observe pre‑harvest intervals and ensure residues remain below legal limits.
Monitoring continues after treatment. Place yellow sticky traps near plant canopies to capture adult mites and assess population trends. Record temperature, humidity, and spray dates in a logbook to correlate environmental conditions with mite activity.
Integrating these practices—environmental regulation, sanitation, physical removal, biological augmentation, and judicious chemical use—provides comprehensive management of mite problems on eggplant cultivated in greenhouse environments.