2 Host Plants Ash – Fraxinus Oak – Quercus Sycamore – Platanus Maple – AcerDogwood – CornusGrapes - VitisAnd others….
3 Causal OrganismAnthracnose 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. SycamoreSmall 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.SycamoreSycamore
6 Disease CycleThe 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 ClinicCornell University Fact Sheet