Notes on Raspberry Diseases
Cane botrytis

Identification

Cane botrytis is often confused with spur blight. The two diseases frequently occur together but cane botrytis is usually more serious. Infections begin on old senescing leaves and travel down the leaf vein to the cane. Cane lesions are dark brown, spread up and down and cover several internodes. Lesions are lighter brown than spur blight lesions and may exhibit zones or bands of growth. These cane lesions turn greyish white in the winter months. Fruiting structures or sclerotia, are formed on overwintering lesions. These look like small black grains of rice imbedded in the lesion. Infected buds are more susceptible to winter injury and are slow to break growth in the spring.

Cane botrytis symptoms on raspberry primocane

Period of Activity

Overwintering sclerotia produce grey masses of conidia in damp spring weather. However, botrytis inoculum can come from many sources of decaying plant debris. Infections occur through older senescing raspberry leaves in mid-late summer. Cane lesions expand rapidly in late summer.

Monitoring

Inspect overwintering canes for sclerotia. Watch new canes for dark lesions that spread on the lower and middle portion of the cane.

Management notes

Keep rows narrow and control weeds to improve drying in the row. Early fungicides are important to reduce overwintering inoculum. Fungicides used for control of botrytis fruit rot may also help to suppress cane botrytis. Field observation suggests Nova and Titan are very susceptible to this disease.

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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