Silver maples (Acer saccharinum) grow in moist soil along the banks of rivers and lakes, and will even grow in standing water. They have extensive root systems that will disrupt paved areas, and invade septic tanks and water lines. They are hardy in zones 3 through 9, and should be planted in woodland or native plant areas. Silver maples have brittle wood that breaks easily, and are prone to numerous diseases and pests.
The fungus that causes anthracnose can affect the leaves, shoots and limbs of silver maples. Infected leaves develop irregular brown blotches or necrotic areas. Buds and new shoots can be distorted or killed by the disease. Lesions can girdle and kill infected twigs and branches. Repeated bouts of infection can weaken silver maples and cause their death. Remove and destroy infected limbs, as well as debris from around infected trees. Apply a fungicide approved for anthracnose according to the manufacturer's instructions.
Cankers are dead areas of bark and wood caused by injuries or disease. Diffuse cankers, such as those caused by cytospora fungi, are shallow with discolored bark around the edges. They grow rapidly and infected trees usually die.
eutypella and nectria fungi cause target cankers when they grow through the bark of dormant silver maples. During the growing season, the trees grow healthy callous tissue around the canker. As the cycle is repeated each year, the rings around the cankers resemble targets.
The fungus rhytisma forms raised black spots on the leaves of silver maples that look like drops of tar. Although the spots affect appearance, the disease does not damage the tree's health. Remove and destroy fallen leaves from around infected trees to prevent the spread of the disease. Tar spots are difficult to control, but a fungicide may help.