Birch trees are popular landscaping trees because of their unique look and graceful arches. But birches do have some weaknesses, including a susceptibility to infection and disease. Knowing how to recognize signs and symptoms of disease and being able to take prompt, effective action is the key to keeping your birch tree happy and healthy for years to come.
In the event that localized problems with your birch tree start to appear, you will notice dead leaves, spots on leaves, wilting branches or blackened or brittle branches. To effectively remove localized infections, you will need rubbing alcohol, cleaning rags and pruning shears, as well as a garbage bag. Wipe the shears down with rubbing alcohol after every cut. Each piece of debris must go into the garbage bag, since both fungal and bacterial infections can reinfect a tree if they are left on the ground. You should not compost these materials but throw them away or burn them.
Birch Tree Forification
Many birch trees can overcome diseases and infections on their own if they are properly fortified early in the infection. Proper soil and watering situations are important. Only water your tree in the early morning using a soaker or drip hose so that the water has time to evaporate off the leaves and it does not splash up onto the bark or leaves. Evergreen fertilizers are best for birches and should be applied to aeration holes in early May. Generally acidic fertilizers are best because birches like acidic soil and will maintain their health better in that environment.
Pesticides, Fungicides and Bactericides
While many problems can be treated without chemicals, insects in particular may be difficult to combat once they have infected a tree. If you notice tiny yellow spots on your birch tree's leaves, you will need to use a foliar spray right away to control birch leafminer. These little insects tend to cause aesthetic problems and leaf distortion. If the yellow spots are larger than dimes, you should not use an insecticide, but rather attempt to fortify your tree with fertilizer and mulching. The other major birch pest, the birch borer, will destroy a tree if it manages to destroy the crown. To control birch borers, you will need to consult an entomologist to determine what class you have, then apply insecticide to the bark of the tree to attempt to destroy the borers before they kill the tree or spread to others.
Fungicides and bactericides can be applied as preventative measures or as last resorts. But most fungal infections--with the exception of root rot, which is essentially irreversible--can be controlled through sterile pruning and careful disposal. The same is true for many bacterial infections, such as the types that cause cankers.