The silver birch, also known as the white birch, grows from 40 to 50 feet in height with a slender trunk that seldom exceeds a foot in diameter. The feature that distinguishes it from the rest of the birch trees is its flaking sliver/white bark. The silver birch tree is susceptible to the same problems as other birch tree species.
The larvae of the birch leafminer burrows into the leaves of the silver birch tree looking for food. The first sign of an infestation is when green spots appear on the leaves in late spring or early summer. The spots change to unsightly brown patches. While the infestation in and of itself will not kill the tree, it does weaken it, making the tree susceptible to an attack by the bronze birch borer.
Bronze Birch Borer
The bronze birch borer can cause a great deal of damage. As with the birch leafminer, it is the larvae that causes the damage. They bore into the phloem, the tissues that carry nutrients to all parts of the tree, and the cambium, the layer that is responsible for growth of stems and roots after the first year. The insects’ boring stops the flow of sap, killing the tree. Repeated infestations can kill a tree in 2 to 3 years.
Anthracnose is a group of fungal diseases that attack a wide variety of shade trees, including the silver birch. In birch trees, it causes defoliation when there is unusual cool and wet weather just when the buds break out. One attack will not do permanent damage, but successive infections stunt the growth and leave the tree open to other types of stress. The buds could be killed, as could any of the twigs, leaves and any branches that are smaller than 1 inch in diameter. Early loss of leaves will leave the tree in a weakened condition and open to infestation by the borer and damage from the winter weather. The fungus will appear as small, irregular, circular brown spots with a darker brown around the edges.
Slime flux is a bacterial disease that attacks both the center of the tree and the bark. The slime that oozes from the tree is poisonous to areas of the tree responsible for the tree’s growth, and it will kill grass or other growing things it happens to fall on. It also attracts insects, who use it as a food source.
The wood inside the tree will turn a yellow-brown in color and have a wetter-than-normal consistency. The wood under that bark will exhibit dark streaks in the wood from the current year.