How to correctly spray for spider mites with phytovirus? - briefly
Dilute the phytovirus to the label‑specified rate, then spray until both leaf surfaces and undersides are fully wet; repeat applications every 7–10 days until spider mite populations are eliminated.
How to correctly spray for spider mites with phytovirus? - in detail
Effective control of spider mites using a phytovirus spray requires precise preparation, application, and post‑treatment monitoring. Follow these steps to achieve reliable results.
Prepare the inoculum. Grow the virus on a susceptible host plant under controlled conditions, harvest infected tissue, and grind it in a sterile buffer (pH 6.5–7.0) containing a non‑ionic surfactant at 0.05 % v/v. Filter the suspension through a 0.45 µm mesh to remove debris while retaining viable viral particles. Verify concentration with a spectrophotometer; aim for 10⁸ – 10⁹ PFU ml⁻¹.
Adjust the spray mixture. Add a suitable adjuvant (e.g., 0.1 % spreader‑sticker) to improve leaf coverage and virus adherence. Maintain the final volume at 1 – 2 l per 100 m² of canopy. Keep the solution cool (≤ 20 °C) and protect it from direct sunlight to preserve viral activity.
Select the optimal timing. Apply during early morning or late afternoon when leaf surface temperature is 15 – 25 °C and relative humidity exceeds 70 %. Avoid periods of rain forecast within 24 h, as precipitation will wash off the virus.
Calibrate the sprayer. Set nozzle pressure to deliver droplets with a median diameter of 100 – 150 µm, ensuring thorough coverage of the underside of leaves where mites reside. Use a flow meter to confirm a delivery rate of 200 ml m⁻².
Execute the application. Spray uniformly, moving in overlapping passes to prevent gaps. Verify wetness by visual inspection; leaves should appear uniformly moist without runoff.
Post‑application care. Maintain canopy humidity above 60 % for 48 h by misting or using humidifiers. Monitor mite populations weekly with a leaf brush sample. Record virus efficacy by comparing mite counts before treatment and at 7‑day intervals.
Repeat the cycle. If mite density remains above economic threshold, re‑apply the virus after a 10‑day interval, respecting the maximum of three applications per growing season to avoid resistance buildup.
Document all parameters—virus strain, concentration, adjuvant type, environmental conditions, and mite counts—to enable reproducibility and facilitate future adjustments.