Causal Organisms: Leptosphaeria coniothyrium (Cane blight); Didymella applanta (Spur Blight)

Crops Affected: caneberries (raspberry, blackberry, etc.)

Disease Cycle:

• These fungal diseases overwinter on infected floricanes (fruiting canes) or canes
• Lesions (spots) on the canes mature as spring draws closer
• Within the lesions, fruiting bodies (pycnidia) produce sexual spores called ascospores
  • During rainy periods, the pycnidia produce and release spores
  • These spores can be blown to infect new plants or may be spread by rain splash
  • Asexual spores (conidia) may also be spread between plants by rain splash

Symptoms:

• An infection begins at a wound site or at an abrasion on the cane

Cane Blight

• Black, pimple-like fruiting structures may be visible on the canes

• • Dark areas develop up and down from that point
  • Laterals (secondary growth) and leaves wilt
  • Affected canes become brittle and snap off easily
  • Producing canes may die between flowering & fruiting

Spur Blight

• Infections begin as a brown or purplish discolouration at the point of leaf attachment on the canes
  • Discolouration will spread up and down from that point
  • Leaves may become chlorotic (yellowed)
• Buds may fail to break in the year following infection

Conditions Favouring Disease:

• High humidity / Rainy periods
• Cool, rainy weather
• Poor air circulation
• Wound sites or abrasions
• Presence of infected canes / fruiting bodies

Management:

• Choose a suitable planting site
• Use clean, disease-free planting stock
• Ensure proper plant spacing
• Thin canopy to improve canopy ventilation and air circulation, as well as reduce mechanical injury from cane rubbing
• Avoid mechanical injury / wounding to canes
• Remove and destroy old and diseased canes (old and young) after harvest
• Control weeds
• Registered fungicides may be applied