When to spray black currants for soil mites? - briefly
Apply a miticide in early spring, just before bud break, when soil temperatures reach about 10 °C. Repeat the spray in late summer, after fruit harvest and before leaf drop, to cover the peak activity of soil mites.
When to spray black currants for soil mites? - in detail
The most effective period for treating blackcurrant bushes against soil‑dwelling mites coincides with the early stages of mite development and the vulnerable phases of the plant. Apply a miticide when the following conditions are met:
- Soil temperature reaches 8–10 °C (46–50 °F) for several consecutive days, indicating that mite eggs are hatching.
- Young shoots are just emerging, before leaf expansion, because mites feed most intensively on tender tissue.
- Soil moisture is moderate; avoid application after heavy rain or during drought, which reduces product penetration and increases phytotoxic risk.
- The crop is not in the fruit‑set stage; spraying during flowering or fruit development can damage blossoms and reduce yield.
Typical spray schedule:
- First application: early spring, when buds swell and soil temperature meets the threshold above.
- Second application: two weeks later, targeting the first generation of mobile mites.
- Optional third application: late spring, if monitoring shows a resurgence of activity before canopy closure.
Monitoring guidelines:
- Inspect roots and lower stems weekly using a hand lens; count live mites per 10 cm of root.
- Record temperature and moisture data to correlate with mite population spikes.
- Adjust timing if thresholds are reached earlier or later than expected.
Product considerations:
- Use systemic acaricides that translocate to roots; ensure the label permits use on blackcurrant.
- Observe pre‑harvest intervals; typically, a minimum of 14 days before fruit harvest is required.
- Rotate active ingredients to prevent resistance; follow the recommended class rotation schedule.
By aligning applications with soil temperature, plant phenology, and moisture conditions, control of soil mites becomes both efficient and safe for the crop.