Actinidia arguta 'Issai' Blackened Leaves & Stems: Fungal Suspects

Black Stem Rot on Hardy Kiwi: Alternaria or Pleospora?

A newly repotted hardy kiwi (Actinidia arguta 'Issai') in London with blackening, curling leaves and stems likely has a soil-borne fungal infection—Alternaria (black stem rot) or Pleospora—introduced via garden soil in the potting mix.

Immediate Steps

1. Isolate plant.
2. Remove all blackened tissue (leaves, stems) back to green.
3. Repot in sterile, peat-based mix (no garden soil).
4. Apply sulfur dust or copper fungicide to crown/soil per label.
5. Bright, airy location. Gradual sun exposure.

Prevention

• Always use sterile potting media for containers.
• Water at base; keep foliage dry.
• Avoid overwatering—kiwis hate wet crowns.

Diagnosis Confirmation

Photos sent to a plant pathologist (e.g., jdcawly@mckendree.edu) or local RHS advisory service can confirm the fungus. UK-specific fungicide labels differ from US.

Act fast—kiwi vines can collapse quickly from crown rot.