Cane and Leaf Spot
Sphaerulina westendorpii (formerly Septoria rubi) on Rubus; Diaporthe ampelin...
2 host plants
Last updated
Cane and leaf spot creates purple or brown spots on berry canes and leaves. You see lesions expand and girdle canes, causing branch death. The disease spreads via water splash during wet weather. Remove infected canes, improve drainage, avoid overhead irrigation, and apply fungicides.
Leaf spot and blotch diseases are primarily cosmetic on established plants, though repeated years of heavy infection can weaken them. Rake up and remove fallen leaves to reduce the spore load going into the next season. Avoid overhead watering that splashes spores from the ground onto lower leaves. If the problem is severe, protective fungicide sprays during spring leaf emergence can help, but sanitation does more than chemistry for most leaf spots.
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Management
Cool, wet weather; high humidity; extended leaf wetness; poor air circulation; dense canopies; overhead irrigation; moderate temperatures (60-70°F optimal for sporulation)
Cultural Controls
- Remove and destroy infected leaves. Leaves may be composted if completely decayed before spring. Make use of any practice that encourages decomposition of fallen leaves prior to spring bud break, such as mowing or flailing. Apply urea to leaves after leaf fall in autumn to enhance decomposition of fallen leaves.
- Rake and destroy leaves in fall. Grow other, more resistant species of Crataegus.