How to treat spider mites on raspberry? - briefly
Apply a miticide such as abamectin or neem oil, covering all leaf surfaces—including undersides—and repeat applications every 7–10 days while monitoring mite levels. Complement chemical treatment with cultural practices: prune affected shoots, maintain adequate irrigation, and introduce predatory mites (e.g., Phytoseiulus persimilis).
How to treat spider mites on raspberry? - in detail
Spider mites are tiny arachnids that feed on raspberry foliage, causing stippling, yellowing, and leaf drop. Early detection relies on inspecting the undersides of leaves for fine webbing and moving specks. A hand lens reveals the mites, which are typically 0.5 mm long and reddish‑brown.
Cultural practices reduce population buildup. Remove all plant debris after harvest, because mites overwinter in leaf litter. Space plants 30–45 cm apart to improve air circulation and lower leaf humidity, conditions unfavorable for mite development. Water the rows with a fine spray early in the day; wet foliage discourages mite activity and washes away eggs.
Biological agents provide sustainable control. Release predatory mites such as Phytoseiulus persimilis or Neoseiulus californicus at a rate of 10–15 k per plant when mite numbers exceed 5 mites per leaf. Apply a dilute solution of neem oil (1 % active ingredient) or horticultural oil (2–3 % v/v) every 7–10 days; both substances suffocate mites and are safe for beneficial insects when used as directed. For severe infestations, introduce entomopathogenic fungi (e.g., Beauveria bassiana) at 1 × 10⁸ spores L⁻¹, repeating applications after rain events.
Chemical options should be reserved for emergency situations. Select a product containing abamectin, spirotetramat, or bifenthrin, applying the lowest effective dose according to label instructions. Rotate active ingredients to avoid resistance; a 14‑day interval between applications of the same class is recommended. Observe the pre‑harvest interval (PHI) to ensure residue compliance.
Monitoring continues throughout the growing season. Use sticky traps placed at canopy height to gauge predator presence and mite pressure. Record mite counts weekly; when the threshold of 10 mites per leaf is reached, initiate the integrated control sequence described above. Maintaining a balanced ecosystem, combined with timely cultural, biological, and, when necessary, chemical measures, keeps spider mite populations below damaging levels and preserves raspberry yield and quality.