Disease	Symptoms	Pathogen/Cause	Management
Anthracnose	Norway maple--narrrow, purple to brown streaks occur along the leaf veins. Sugar maple--large, irregular, brown or red-brown areas develop along and between the veins similar to injury due to drought and heat stress. Small brown fruiting structures of the fungus are found near the affected leaf veins. Under very wet spring conditions, some defoliation can occur.	Discula (Gloeosporium)	Prune dead twigs and branches. Rake and destroy fallen leaves. Usually, little damage occurs and no treatment is necessary. In a nursery, apply mancozeb or mancozeb + thiophanate methyl at bud break and at 7- to 10-day intervals until the weather dries and warms to daily averages above 65 degrees F.
Bacterial Leaf Scorch	Red maple leaves brown along the margin and have a reddish-brown zone with a yellow halo separating it from the green tissue beginning mid July. Scorching progresses toward the midrib in a wavy line.	Xylella fastidiosa	Affected trees may survive for years but are more sensitive to other stresses such as deicing salts and limited growing space. Spread is via spittlebugs and leafhoppers.
Bleeding Canker	Reddish-brown cankers develop in the inner bark of the main trunk and branches. The bark over the canker becomes sunken and reddish-brown sap oozes out. Leaves wilt and branches die.	Phytophthora cactorum	Remove the infected tree and do not replace it with a woody ornamental until the soil has been fumigated and aerated thoroughly.
Decline	Tree growth slows. Branch dieback progresses until much of the tree is dead.	Combinations of poor soil aeration, poor soil drainage, deicing salt damage, high temperatures at the site, drought, excavation, soil compaction, paving close to trees, Verticillium wilt, and Armillaria root rot (exact combination depending upon the site) combine to weaken and kill the tree.	Protect the tree from as many stresses as possible.
Eutypella Canker	A pronounced bulge of callus develop around an area of dead, but tightly attached bark on one side of the trunk. Or, the canker may completely girdle the tree. Often, there is a dead branch stub in the center of the cankered area. Decay fungi enter the cankers, making the tree very susceptible to breakage.	Eutypella parasitica	Remove trees with cankers on the main trunk. In the case of highly valuable trees, use a sharp chisel to remove all of the cankered wood and fungal mat plus 1-1.5 inchesof the healthy bark and wood. Remove affected branches, cutting 4-6 inches below the canker when the weather is dry. When the long range plan for a tree is to remove the lower limbs, do so when those limbs are less than 1 inch in diameter.
Fomes Rot	A fungal fruiting structure that is hard, gray-topped, hoof-shaped, and up to 6 to 8 inches across enlarges perennially. The underside of the "hoof" is white with millions of tiny pores in which the spores are formed. Heart rot and dying limbs may be apparent.	Fomes fomentarius	A tree with fungal fruiting structures on the trunk should be removed promptly if it is in a location where property damage may occur or where people or pets could be struck by falling limbs or the falling tree.
Ganoderma Root Rot	Very distinctive shelf-like fruiting structures form annually on the wood singly or in overlapping clusters. They are brown to reddish brown on top with a cream to white-colored margin, and may become 14 inches across. The upper surface may appear to have been varnished. Branches and eventually the entire tree dies as the root rotting progresses.	Ganoderma lucidum	A tree with fungal fruiting structures on the trunk, butt, or roots should be removed promptly if it is in a location where property damage may occur or where people or pets could be struck by falling limbs or the falling tree.
Laetiporus Root Rot	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 millions of tiny pores in which the spores are formed. New shelves form on the wood the following summer and autumn. The bark where the fruiting structure forms is slightly depressed and cracked.	Laetiporus sulfureus (formerly Polyporus sulfureus)	Fruiting structures form long after most of the damage has been done. Infected trees are very prone to wind breakage even before the fungus begins to form fruiting structures and should be removed at the first sign of infection.
Leaf Spot	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 the upper surface of the spots.	Phyllosticta minima	See anthracnose control above.
Powdery Mildew	White fungal growth develops on the upper surface of leaves in the late summer and autumn.	Phyllactinia	No control is necessary since the disease begins too late to cause significant damage.
Tar Spot	Oval to irregularly shaped shiny black spots up to 1/2 inch in diameter form on the leaves of silver or red maples.	Rhytisma acerinum or R. punctatum	No control measures are necessary.
Verticillium Wilt	Early symptoms of Verticillium wilt include heavy seed production, leaves that are smaller than normal, and the browning of the margins of leaves. Frequently, the foliage on only one side of a tree wilts. The wood under the bark of wilting branches is discolored with green to black streaks. The smallest branches may not exhibit the discoloration.	Verticillium	Do not replant susceptible species where a specimen was killed by Verticillium. When a tree exhibits mild symptoms, prune out affected limbs and water and fertilize to maintain tree vigor. Some trees recover.

COMMON NAME	TRADE NAME
mancozeb	Dithane, Mancozeb
mancozeb + thiophanate methyl	Duosan, Zyban