Blackberry: Leaf and cane spot

• Categories: Blackberry Blackberry Diseases Small Fruits
• Last review date: 2025-12-04 03:02

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

See "Using Integrated Pest Management (IPM) in the Landscape" for successful problem management techniques.

Non-chemical Management

Select non-chemical management options as your first choice!

• 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.

Chemical Management

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

Approved Pesticides

If you choose to use a pesticide, some examples of products that are legal in Washington are listed below. Some products are labeled for just INDOOR or just OUTDOOR use, or may allow both uses. Be sure to choose a product appropriate for your situation. Always read and follow all label directions.

• Monterey Liqui-Cop Copper Fungicidal Garden Spray
  Active ingredient: copper-ammonia complex
  EPA registration number: 54705-7
• This list may not include all products registered for this use.