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Raspberry cane diseases

Quick facts

  • Spur blight, anthracnose and cane blight are fungal diseases that infect raspberries.
  • Cane diseases can kill part or all of the raspberry cane. This reduces yield the following year.
  • Cane disease fungi thrive in wet weather and spread on splashing water.
  • Reduce cane diseases by maintaining narrow beds and open canopies within the raspberry patch.
  • Remove all floricanes and infected primocanes after harvest.

See Growing raspberries in the home garden for more information on keeping plants healthy.

How to identify cane diseases

  • Cane diseases can infect red raspberry, black raspberry and blackberry.
  • Some cane disease fungi survive on wild Rubus spp. and other woody plants.
  • Anthracnose is most severe in black raspberries. It can cause some damage to red raspberries as well. 
  • Cane blight and spur blight can cause significant damage to red raspberry.

The best time to identify all three cane diseases is to look at primocanes in late summer and early fall. 

  • Primocanes are first year canes that sprout in the spring.
  • The green fleshy stalks of primocanes are easily infected by the fungi that cause cane diseases.
  • The unique symptoms of each disease can be seen on primocanes in late summer and early fall before the canes turns brown.

In the spring, the overwintering canes are often dead from the disease. These diseased, dead canes are often mistaken for winter injury. Disease symptoms are not easy to see in brown bark and dead canes. 

  • When winter injury is the only cause of cane death, the canes die back to snow level and the floricanes will sprout in living buds below the snow level.
  • In raspberry patches infected with cane diseases, the floricanes die to the ground or to the infected part of the cane.

Symptoms

Each disease has specific symptoms and each infects a different part of the cane.

  • Spur blight infects the leaves and the node (the part of the cane where the leaves grow).
  • Cane blight infections start anywhere the cane is wounded.
  • Anthracnose infects the parts of the cane between the leaves (internodes).
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How do cane diseases survive and spread?

  • Raspberry cane diseases are caused by three different fungi.
    • Cane blight is caused by Leptosphaeria coniothyrium.
    • Spur blight is caused by Didyimella applanata.
    • Anthracnose is caused by Elsinoe venata.
  • These fungi can be brought into a garden on raspberry plants that are infected with the disease or from nearby, wild plants.
  • Fungi survive winter in infected floricanes.
  • Fungal spores of all three diseases are produced on infected floricanes during wet weather.
  • The fungi that cause anthracnose and cane blight only spread by splashing water. The fungus that causes spur blight spreads by the wind as well as splashing water.
  • Infection occurs on different plant parts for each disease.
    • The anthracnose fungus infects only young green tissue. It can infect primocanes, leaves, fruit, flower buds, and leaf stems.
    • The cane blight fungus infects canes through wounds only. Wounded young canes quickly develop severe disease. By fall, canes of red raspberry are resistant to infection.
    • The spur blight fungus infects mature leaves on the lower third of the plant. The fungus grows through the leaf stem into the cane. Young leaves are resistant.
    • None of the cane diseases infect the roots.
  • Fungal spores are produced on infected plant parts throughout the growing season whenever wet weather occurs.
  • Splashing water moves spores throughout the plant and to neighboring plants.

How to manage cane diseases

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Michelle Grabowski, Extension educator and Thaddeus McCamantt

Reviewed in 2019

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