Maple Diseases

Informational table showing disease name, symptoms, pathogen/cause, and management of diseases.

Disease Symptoms Pathogen/Cause Management Norway maple: narrrow, purple to brown streaks occur along the leaf veins. Sugar Prune dead twigs and maple: large, irregular, brown branches. Rake and destroy or red-brown areas develop fallen leaves. Usually, little along and between the veins damage occurs and no similar to injury due to treatment is necessary. In a drought and heat stress. Small, nursery situation, apply a brown fruiting structures of fungicidel at bud break and at the are found near the 7- to 10-day intervals until the affected leaf veins. Under very weather dries and the daily wet spring conditions, some average temperature is above Anthracnose defoliation can occur. Discula (Gloeosporium) 65°F. Leaf margins on localized, individual branches brown in mid- to late July. The light-brown area is separated from green tissue by a dark Leafhoppers and spittle bugs reddish-brown band and a carry the bacteria from tree to narrow but distinct yellow tree. Promote plant vigor by Bacterial leaf scorch (red halo. Leaves may fall in protecting the tree from maple) August. Xylella fastidiosa stresses. Reddish-brown cankers develop in the inner bark of the main trunk and branches. Remove the infected tree and The bark over the canker do not replace it with a woody becomes sunken, and ornamental until the soil has reddish-brown sap oozes out. been fumigated and aerated Bleeding canker Leaves wilt and branches die. Phytophthora cactorum thoroughly. Depending upon the site, combinations of poor soil aeration, poor soil drainage, deicing salt damage, high temperatures at the site, drought, excavation damage, soil compaction, paving close Tree growth slows. Branch to trees, verticillium wilt, and dieback progresses until much root rot weaken and Protect the tree from stresses, Decline of the tree is dead. kill the tree. particularly insect defoliation. A fungal fruiting structure that is hard, gray topped, hoof A tree with fungal fruiting shaped, and 6 to 8 inches structures on the trunk should across and enlarges be removed promptly if it is in perennially. The underside of a location where property the “hoof” is white with tiny damage may occur or where pores in which the spores are people or pets could be struck formed. Heart rot and dying by falling limbs or the falling root rot limbs may be apparent. Fomes fomentarius tree. Very distinctive shelf-like fruiting structures form annually on the wood singly or in overlapping clusters. They are brown to reddish brown on A tree with fungal fruiting top with a cream to white structures on the trunk, butt, or margin, and may reach 14 roots should be removed inches across. The upper promptly if it is in a location surface may appear to have where property damage may been varnished. Branches and occur or where people or pets eventually the entire tree die could be struck by falling root rot as the root rotting progresses. Ganoderma lucidum limbs or the falling tree. Massive clusters of bright sulfur-yellow to salmon to bright-orange, shelf-like fruiting structures that turn white with age initially form in the summer or autumn on the wood of the tree but fall off during the winter. The underside of the fruiting structure has tiny pores in Fruiting structures form long which the spores are formed. after most of the damage has New shelves form on the been done. Infected trees are wood the following summer very prone to wind breakage and autumn. The bark where even before the fungus begins the fruiting structure forms is to form fruiting structures and slightly depressed and Laetiporus sulfureus (formerly should be removed at the first Laetiporus root rot cracked. Polyporus sulfureus ) sign of infection. Leaf spots up to 1/4 inch in diameter with a pronounced purple border are round or irregular in shape. Tiny, black fungal fruiting structures dot Leaf spot the upper surface of the spots. Phyllosticta minima See anthracnose control above. White fungal growth develops on the upper surface of leaves No control is necessary since in the late summer and the disease begins too late to Powdery mildew autumn. Phyllactinia cause significant damage. Oval to irregularly shaped, shiny, black spots up to ½ inch in diameter form on the leaves Rhytisma acerinum or R. No control measures are Tar spot of silver or red . punctatum necessary.

Page 2 Maple Diseases Early symptoms of verticillium wilt include heavy seed production, leaves that are smaller than normal, and browning of the margins of leaves. Frequently, the foliage Do not replant susceptible on only one side of a tree species where a specimen was wilts. The wood under the killed by Verticillium. When a bark of wilting branches is tree exhibits mild symptoms, discolored with green to black prune out affected limbs and streaks. The smallest branches water to maintain tree vigor. may not exhibit the Some trees recover. Do not Verticillium wilt discoloration. Verticillium fertilize heavily.

Declining maple in mid-summer.

Page 3 Maple Diseases Tar spot.

Tar spot.

Verticillium wilt discoloration of xylem.

Page 4 Maple Diseases Verticillium wilt.

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Page 5 Maple Diseases