According to the USDA Forest Service, birch trees are "prized for their outstanding bark characteristics and graceful, delicate foliage." These trees can live for 40 to 50 years if properly maintained. However, there are birch tree diseases that can attack these trees and bring them down far earlier in their lives. The best way to keep your birch tree "happy" and healthy is to be aware of the treatments for birch tree disease and be ready to use them at the first sign of trouble.
Pruning your birch tree correctly and using sterile technique is important if it has diseases like cankers or leaf spot. Prune the tree in late spring after the leaves have reached full size, and swab your pruning tools with rubbing alcohol after each cut to prevent spreading the disease to parts of the tree that are not presently impacted. Dispose of all infected plant material by burning or throwing it away in a sealed bag.
While most birch tree owners would like to avoid treating the areas around their trees with chemical insecticides, if your tree has developed a birch borer infection, then you will have to use insecticides if you hope to control it. Soil drenching helps contain the insecticide and keep it out of the air. Birch miners and borers can be treated with a dimethoate soil drench, but the USDA adds that generally foliar sprays will also be necessary to fully control the infestation.
In some cases, changing the way that you treat your birch tree and its immediate environment can help it recover from a fungal infection. Make sure that the tree is getting enough light and air circulation in its branches by pruning in late spring, if necessary, and removing undergrowth and other trees that might be crowding or overshadowing the plant. Additionally, always water your birch using a drip hose to prevent water from sitting on the leaves and creating a situation conducive to mold and mildew problems.