Early Leaf Spot
Phyllosticta cotoneastri (primary); Entomosporium maculatum (secondary)
13 host plants · Fungal
Last updated
This profile synthesizes data from multiple published sources. Expert field review is in progress.
Early leaf spot creates brown spots on foliage early in the growing season. You notice spotting develop in spring with wet weather. The fungus spreads via water splash and air. Manage through leaf removal, improved air flow, and 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.
Quick Reference
Management
Early spring (BBCH 10-14: leaf expansion phase); young emerging foliage most susceptible. Infection window typically March-May in maritime PNW.
Spring; cool wet conditions (50-65°F) with 8+ hours leaf wetness during new leaf expansion. Rain-splash dispersal from infected debris on soil.
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.