Birch Leaf Spot

by Sherrie Smith and Jason Pavel

Birch Leaf Spot – Cryptocline betularum

Photo by Sherrie Smith, University of Arkansas Cooperative Extension

Are leaves suddenly falling off your birch tree in the summer?

Homeowners are often frightened by the sudden defoliation of their birch tree in mid to late summer. Birch Leaf Spot or blight, caused by Cryptocline betularum, can cause severe premature leaf shed. Up to 30% or more of the tree’s leaves may end up on the ground. Fortunately, this occurs late enough in the season that tree health is not much affected. 

Control consists of cleanup of the fallen leaves and tree care that includes proper fertilization and water. If repeated severe defoliations occur, fungicides containing chlorothalonil may be used. Apply fungicides at bud break in the spring and continue at two intervals for 2 or 3 applications. This is generally not necessary unless the tree is very young and vulnerable.

Take Aways

• Clean up all fallen leaves.
• Provide proper fertilization and water.
• Apply fungicides early in the season to young trees.

This work is supported by the Crop Protection and Pest Management Program [grant no. 2017-70006- 27279/project accession no. 1013890] from the USDA National Institute of Food and Agriculture.