1. Anthracnose on Shade Trees
Insects & Diseases

2. Host Plants Ash – Fraxinus Oak – Quercus Sycamore – Platanus
Maple – Acer
Dogwood – Cornus
Grapes - Vitis
And others….

3. Causal Organism
Anthracnose is caused by various species of fungi in the genus Apiognomonia.
Each species is specific to the host tree it infects.

4. Symptoms Small dead spots on leaves. Dead leaf margins and tips.
Sycamore
Small dead spots on leaves.
Dead leaf margins and tips.
Brown, dead leaf areas along the leaf veins.
Premature defoliation.
Twig death.
Formation of a witches broom.
Sycamore
Sycamore

5. Ash
Sycamore
Sycamore
Sycamore

6. Disease Cycle
The fungus survives the winter on stem cankers fallen leaves.
In the spring the wind carries the spores from the cankers to developing leaves and twigs.
Young, infected twigs are girdled and killed.
New spores forming on infected leaves and twigs are blown or splashed to nearby foliage. Infected leaves shrivel and fall.
Cool, wet spring weather (50-55 degrees F.) favors the spread of this disease.

7. Management Remove fallen leaves.
Prune out diseased twigs and branches.
Open up the canopy for better air circulation and light penetration.
Spray a fungicide labeled for anthracnose beginning at bud break and continuing weekly until the weather warms into the 60’s.

8. References Penn State University Plant Disease facts
Iowa State University Plant and Insect Diagnostic Clinic
Cornell University Fact Sheet