What should be used to spray spider mites in a cucumber greenhouse? - briefly
Apply a «horticultural oil» or a neem‑based miticide as a fine spray to the foliage, ensuring thorough coverage of leaf undersides. Repeat applications every 5–7 days until mite populations decline.
What should be used to spray spider mites in a cucumber greenhouse? - in detail
Effective control of spider mites in cucumber production requires a spray regimen that combines rapid knock‑down, residual activity, and compatibility with greenhouse environments.
Chemical miticides provide immediate reduction of populations. Products based on abamectin (0.5–1 mg a.i./L) or spinosad (60–80 g a.i./L) are registered for cucurbit crops and retain activity for 5–7 days when applied at the recommended concentration. Both compounds exhibit systemic movement within foliage, enhancing coverage of concealed leaf undersides.
Horticultural oils and insecticidal soaps act by suffocating mites and are safe for edible produce. A light mineral oil (1–2 % v/v) or potassium salts of fatty acids (2–3 % v/v) should be sprayed until runoff, ensuring thorough wetting of leaf surfaces. Re‑application every 3–4 days prevents resurgence, particularly under high humidity conditions.
Botanical extracts, notably neem oil (1–2 % v/v) and rosemary oil (0.5 % v/v), interfere with mite reproduction. Use as a preventive measure early in the season; efficacy declines after 5 days, requiring frequent intervals.
Biological agents complement chemical options and reduce resistance risk. Predatory mites such as Phytoseiulus persimilis or Neoseiulus californicus are released at 50–100 predators per m² and establish within the canopy. Entomopathogenic fungi (Beauveria bassiana) applied at 1 × 10¹² conidia/L provide infection under temperatures above 20 °C and relative humidity above 70 %.
Application equipment must generate droplets of 20–40 µm to penetrate dense foliage. Fine‑mist or low‑pressure sprayers equipped with adjustable nozzles deliver uniform coverage. Calibration of flow rate (≈ 0.5 L min⁻¹ per 10 m²) and spray volume (≈ 200 L ha⁻¹) ensures optimal deposition.
Resistance management dictates rotating active ingredients with different modes of action. A typical program might follow: abamectin → horticultural oil → spinosad → predatory mite release, repeating the cycle annually.
Safety considerations include pre‑harvest intervals (PHI) of 0 days for oils and soaps, and 3–5 days for abamectin and spinosad. Personal protective equipment (gloves, goggles) is mandatory during mixing and application.
In summary, an integrated approach that combines short‑acting miticides, oils or soaps, botanical extracts, and biological control agents, applied with calibrated fine‑mist equipment and rotated to avoid resistance, delivers reliable suppression of spider mites in cucumber greenhouse production.