Homeowners who want to make their river birches a bit stronger and better able to withstand this disease next year, should consider collection of soil samples from affected trees. The soil samples can be analyzed to determine fertility need of your trees. See your County Extension Office about the procedure for soil sample collection. It might be that a fall application of phosphorus and potash will be needed. These fertilizer materials will help your tree go into the winter a bit stronger and get off to a better start next spring.
Stronger trees are better able to resist diseases such as birch leaf blight.
Also, raking and removal of fallen leaves is a good idea. Diseased leaves which carry-over to next spring will be sources of the fungus which causes the leaf blight. They can be composted and used if the composting is carried out properly. Other practices include a dormant season application of a lime sulfur spray to your trees this winter, and three or four applications of a maneb fungicide following leaf emergence next spring. These will reduce the amount of birch leaf blight and leaf fall later in the season.