WSU Extension


Fruit rot 
Leaf and cane spot 
Brown marmorated stink bug 
Raspberry crown borer 
Redberry mite 
Spotted wing Drosophila (SWD) 

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Caption: Blackberry fruit rot
Photo by: R.S. Byther
Blackberry : Fruit rot
(revision date: 5/6/2014)

Fruit rot is caused by a fungus. The disease is characterized by a watery, soft rot of infected fruit, either in the field or in storage. In moist conditions, the diseased fruit develops a characteristic coating of powdery, gray-brown fungus. The fungus can also attack canes, spreading from infected leaves into the cane and causing pale brown or "watermarked" gray and white lesions. The cane infections may also show fungal growth during humid conditions. The fungus typically overwinters in diseased plant debris and can be spread by wind and splashing water. The disease thrives in cool, moist weather and may cause serious fruit losses.
Management Options

Non-Chemical Management
  • Space plantings, prune, and train to provide good air circulation and reduce humidity.
  • Clean up all plant debris. Destroy or discard (do not compost) diseased materials.
  • Avoid overhead watering.
  • Provide proper culture. Excess fertilizer promotes dense, slow-drying foliage.
  • Pick ripe fruit frequently and thoroughly to reduce losses. Avoid injuring fruit and cool promptly.
Select non-chemical management options as your first choice!

Chemical Management

None recommended


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Caption: Blackberry fruit rot
Photo by: R.S. Byther