Common Problems With Birch Trees
There are more than 60 species of birch tree, including the yellow birch, cherry birch, paper birch and river birch. Birch trees have wide-spreading crowns that make them good shade trees. Common problems with the birch tree include pest infestations and a fungus infection that causes canker.
Bronze Birch Borer
This pest destroys white-barked birches, particularly the European white birch in the Midwest and Eastern United States. During the winter, the insect is a dormant grub waiting under the bark. It pupates into a beetle in the late spring and early summer. The female deposits eggs in cracks in the bark. These hatch in 10 days, chewing through the inner bark. By the fall, the now full-grown bugs will tunnel their way through the branches. Infestation symptoms include dead branches near the top of the tree. To treat, remove infested branches. Avoid herbicides because the tree's roots are near the surface. Keep trees healthy by watering during dry spells and mulching at the base of the tree.
The leaf miner is an insect that attacks the birch tree's new shoots, feeding on the leaves. Blotch mines appear on the leaves where the insect has eaten the inside of the leaf, according to the University of Missouri. Healthy birch trees are not adversely affected by the insect. Stressed and diseased trees should be treated with a systemic insecticide, either through the leaves or into the soil.
Birch Tree Canker
Birch tree canker is caused by a fungus that enters from the soil through wounds on the tree or when young trees are forming. Oval or irregularly shaped sores appear on the trunk, stem or branches of trees. The sores may open and ooze watery sap. The fungus kills the tissues that conduct water, causing both leaf and branch dieback. To treat, remove and destroy the affected branches, according to the University of Wisconsin Extension. Cut cankers from trees and disinfect tools between cuts. Coat any wounds on trees with tree paint to prevent the fungus from entering the tree.
- "Pests and Diseases”; Richard H. Craves and Time-Life Books; 1977
- University of Missouri Extension: Birch Leafminers