Notes on Raspberry Diseases
Cane blight

Identification

Cane blight is a serious raspberry cane disease in Ontario. Diseased canes may die during the winter or they may leaf out erratically in the spring. Infected canes, initially healthy in appearance, may die-back above the point of infection just as harvest begins.

Period of Activity

The pathogen enters primocanes or first-year growth, through wounds and spreads up and down the vascular tissue, which causes the cane to become brittle and weak. Symptoms are most evident the next spring. Severely infected canes do not leaf out in the spring because they are unusually brittle and snap or break easily. Infected canes may leaf out and then die back before harvest.

Monitoring

Symptoms of cane blight look similar to those caused by cane and crown borers. However, cane blight can be diagnosed when you scrape back the bark of infected canes to expose the vascular tissue. The diseased vascular tissue beneath the bark is distinctly brown instead of green. Check the crown and roots for borers, nematodes and diseases, which compound the problem.

Management notes

• Prevent injury to primocanes from rubbing against trellis wires, by machine harvesters or by summer pruning. These injuries are susceptible to cane blight infection. Primocanes can also be wounded when they rub against old canes pruned too high above the ground.
  
• Carefully prune out old fruiting canes close to ground level when canes are dormant.
  
• Avoid pruning or tipping when plants are wet or just before a rain.
  

Learn more...

• Notes on Raspberry Diseases and Insects
• OMAFRA Publication 360 Raspberry Calendar
• OMAFRA Publication 360 Fruit Production Recommendations
• OMAFRA Berry Crops Index page
  

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