When should currants be treated for the kidney tick? - briefly
Treatment should begin as soon as ticks are detected on the plants, preferably during the early growing season (spring to early summer) when larvae are most active. Applying an appropriate acaricide at this stage prevents root damage and preserves fruit quality.
When should currants be treated for the kidney tick? - in detail
Currants are susceptible to the kidney‑tick pathogen, a soil‑borne organism that infects roots and lower stems. Infection begins when zoospores migrate upward during periods of high soil moisture, typically in early spring. Preventive action must precede the first appearance of symptoms, which are usually visible as wilting, chlorotic leaves, and necrotic lesions on the root crown.
Effective control depends on aligning applications with the plant’s phenological stages and environmental conditions that favor pathogen activity. The optimal window occurs:
- Dormant period: before bud swell, when temperatures consistently stay below 10 °C and soil moisture is high. A single treatment at this stage limits zoospore movement.
- Pre‑bloom: as buds begin to enlarge but before flowers open, when temperatures rise to 12‑15 °C. A second application protects emerging vascular tissue.
- Early fruit set: if the first treatment was omitted or weather conditions were unusually wet. Application at this stage reduces colonization of developing shoots.
Monitoring should include weekly assessment of soil temperature and moisture. Degree‑day accumulation of 50‑100 °C days above a 5 °C base signals the transition from dormancy to active growth, indicating the first treatment window. Rainfall exceeding 20 mm within 48 hours increases infection risk and may necessitate an additional spray.
Recommended products are systemic fungicides labeled for kidney‑tick control. Apply at the manufacturer’s recommended rate, ensuring thorough coverage of the root zone. Observe the pre‑harvest interval (PHI) specified on the label, typically 30 days, to avoid residue concerns.
In summary, preventive measures should be timed to the dormant stage, reinforced at pre‑bloom, and, if necessary, repeated during early fruit development. Alignment with temperature thresholds and moisture patterns maximizes efficacy and minimizes crop loss.