How to spray yews for spider mite? - briefly
Apply a fine‑mist spray of insecticidal soap or horticultural oil, thoroughly covering the foliage and stems of the yew, preferably early morning or late evening to avoid leaf scorch. Repeat the treatment every 5–7 days until mites are no longer observed.
How to spray yews for spider mite? - in detail
Treating yew specimens for spider‑mite infestations requires a systematic approach. Begin by confirming the presence of the pest: examine foliage for fine webbing, stippled or yellowed needles, and the tiny, moving mites on the undersides. Early detection prevents severe defoliation.
Select an appropriate control product. Effective options include horticultural oil (5–10 % concentration), neem‑based formulations, insecticidal soap, or a registered miticide such as abamectin. Oil and neem act by smothering and disrupting feeding, while soap kills on contact. Miticides provide systemic action but should be reserved for heavy outbreaks.
Prepare the spray mixture according to label directions. For oil, mix 1 ml of concentrate per liter of water; for neem, 2 ml per liter; for soap, 5 ml per liter. Use warm water (20–25 °C) to improve coverage. Add a non‑ionic surfactant (0.1 % of the total volume) to reduce surface tension and ensure uniform distribution.
Apply the solution during the coolest part of the day, preferably early morning or late afternoon, when temperatures are between 10 °C and 25 °C and humidity exceeds 50 %. Avoid spraying under direct sunlight or when rain is forecast within 24 hours, as these conditions diminish efficacy and increase phytotoxic risk.
Cover all needle surfaces, paying special attention to the undersides where mites congregate. Use a fine‑mist nozzle to achieve a thin, even film; excessive runoff can damage foliage. Repeat applications at 7‑ to 10‑day intervals until populations fall below economic thresholds, typically after three to four treatments.
After each spray, inspect the trees for adverse reactions such as leaf burn or discoloration. If symptoms appear, rinse foliage with clean water and adjust concentration downward. Maintain proper cultural practices—adequate watering, balanced fertilization, and removal of infested debris—to reduce stress and discourage mite resurgence.
Record treatment dates, products used, and observed mite counts. This data supports future decision‑making and helps comply with integrated pest‑management guidelines.