Spot anthracnose is caused by the fungus Elsinoe corni and results in spotting of dogwood flowers, leaves, stems, and fruit. Spots on bracts are reddish-purple and may be as large as 1/10 inch in diameter. Spotting of bracts may be so severe that flowers are disfigured. Badly infected flower buds may never open. Spots on leaves appear as circular to angular dark purple areas, usually less than 1/25 inch in diameter. Diseased leaf tissues often drop out, leaving holes or ragged edges, and severely infected leaves may be reduced in size or killed. Spots on fruit and stems may be dark, and the spots are often slightly raised. Although the disease can be disfiguring, it is not life-threatening. Spot anthracnose is not the same as the very damaging disease dogwood (or Discula) anthracnose.
In most cases this disease doesn't result in significant damage, but severe and repeated infections each year can significantly weaken a tree. Thin the canopy to increase air movement. Choosing to plant species and cultivars with some degree of disease resistance is an excellent option for managing this problem in the landscape.
If spotting becomes severe, fungicides can be used in the spring starting at bud break and continuing until leaves are fully expanded. Apply all chemicals according to directions on the label.
Contact your local Extension office for fungicide and resistant variety recommendations.
