Alternaria Leaf Spot
Alternaria spp.
1 host plant
Last updated
Data Coverage 3 of 6 dimensions
Brown spots with concentric rings appear on leaves during warm, wet weather, causing defoliation. This fungal disease favors warmth and moisture. Remove fallen leaves and improve air circulation.
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.
Quick Reference
Causal Agent
Alternaria spp.
Host Plants
1
Management
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.