WSU Extension

Hortsense

Blackberry : Leaf and cane spot
(revision date: 4/11/2018)


Use Integrated Pest Management (IPM) for successful plant problem management.

Biology
Leaf and cane spot is a fungal disease affecting blackberries (including 'Marion' and 'Santiam') and blackberry hybrids (including 'Boysen' and 'Logan' berries). Leaf symptoms include development of characteristic lesions which are initially purplish, then turn tan to brown. The lesions later develop white centers with brown to purple margins. Cane symptoms are similar, but less noticeable. Severe leaf infections can cause premature loss of leaves, sometimes resulting in considerable leaf drop by late summer or early fall. The fungus overwinters on plant debris and is commonly spread by splashing water. A similar disease may occur on raspberries.
Management Options

Non-Chemical Management
  • Space plantings, prune, and train to provide good air circulation and reduce humidity.
  • Avoid overhead watering.
  • Provide proper culture. Excess fertilizer promotes dense, slow-drying, easily infected foliage.
  • Clean up all plant debris. Destroy or discard (do not compost) diseased materials.
  • Remove old fruiting canes and all dead or damaged canes after harvest. Do not compost diseased materials.
Select non-chemical management options as your first choice!

Chemical Management
IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides

Apply as a delayed dormant spray after training in the spring and after harvest.

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.
  • Monterey Liqui-Cop Copper Fungicidal Garden Spray
    Active ingredient: copper-ammonia complex  |  EPA reg no: 54705-7
  • This list may not include all products registered for this use.
Images
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Caption: Blackberry leaf spots
Photo by: OSU slide library
Caption: Blackberry cane spot
Photo by: OSU slide library
Caption: Blackberry leaf spots
Photo by: OSU slide library