Symptoms of tar spot on maple Courtesy Ohio State University Extension Service

Rhytisma acerinum, Rhytisma punctatum

These dramatic but inconsequential diseases of numerous maple species cause small to almost one-inch diameter tar-like spots on leaves. The fungus overwinters on fallen leaves, then infects the upper surfaces of leaves in spring during moist conditions. Leaf spots are first a yellowish green but by mid to late summer a tar-like mesh of fungal and leaf tissue develops inside the yellowed area. Occasionally some leaf withering and drop occurs but this is not generally serious and fungicide sprays are not generally recommended. If fungicides are required, use a labeled product containing mancozeb or triadimefon.

Information provided by Ohio State University Extension Service

Back to Maple Tree Insects and Diseases

TOP

 

¤ Flat-rate shipping  ¤ Maple Care Kits Including: specially selected fertilizer, mycorrhizal fungi, and a biostimulant. Quality Maple Tree Seeds