How to fight mites on currants in autumn? - briefly
Apply a late‑season acaricide such as sulfur or neem oil after the final harvest, prune heavily infested shoots, and ensure adequate canopy ventilation. Follow with a soil drench of neem or release predatory mites to suppress residual populations before winter.
How to fight mites on currants in autumn? - in detail
Effective autumn management of mite infestations on currant bushes requires a systematic approach that combines monitoring, cultural practices, biological agents, and, when necessary, targeted chemical treatments.
Begin with thorough scouting. Examine foliage weekly from early September onward, focusing on the undersides of leaves where mites congregate. Look for stippled discoloration, fine webbing, and the presence of tiny moving specks. Record population levels to determine whether intervention is warranted.
Cultural measures reduce habitat suitability:
- Remove fallen leaves and fruit debris to eliminate overwintering sites.
- Prune out heavily infested shoots, cutting at least 10 cm above healthy tissue to expose fresh growth.
- Thin canopy by spacing branches 30–40 cm apart, improving air circulation and sunlight penetration.
- Apply a balanced fertilizer in late summer; avoid excessive nitrogen, which promotes rapid leaf expansion preferred by mites.
Biological control options include:
- Predatory mites (e.g., Phytoseiulus persimilis or Neoseiulus californicus). Release rates of 10–15 mites per square centimeter of foliage, applied in the early evening to avoid UV degradation.
- Entomopathogenic fungi such as Beauveria bassiana. Apply a water‑soluble formulation at the manufacturer’s recommended concentration, ensuring thorough coverage of leaf undersides.
- Neem oil sprays at 1–2 % concentration, providing both repellency and mild toxicity to the pests.
If mite numbers exceed economic thresholds (approximately 5–10 mites per leaf), integrate selective acaricides:
- Sulfur dust or liquid formulations, applied at 2–4 g m⁻², repeated at 7‑day intervals until populations decline.
- Spinosad (e.g., 1.5 ml L⁻¹) for rapid knock‑down, observing a pre‑harvest interval of 7 days.
- Abamectin, limited to two applications per season, at 0.5 ml L⁻¹, respecting the label‑specified re‑entry period.
Rotate chemicals with different modes of action to delay resistance development. After each application, wash foliage with a fine spray of water to remove residues and prevent phytotoxicity, especially under low temperatures.
Conclude the season by performing sanitation: collect and destroy all pruned material, fallen leaves, and fruit. Store tools in a dry location to avoid harboring mite eggs. This final step interrupts the life cycle, reducing pressure for the following spring.