Black Leaf Spot

If you have Quaking Aspen trees, it is nearing the appropriate time to treat your aspens for the fungus causing Black Leaf Spot. This disease is most severe during wet weather. The fungus survives in fallen leaves infected the previous year. It will show up in the warmer summer weather as brown flecks with yellow margins later turning to black spots on the leaves. This fungus may also invade twigs. A severe infection may produce early defoliation and reduced growth. It is very important to collect and burn leaves in the fall. Spray trees in the spring, at bud break, with a product called Daconil (follow instructions provided on product) as this will help to prevent a reoccurrence of the fungus. If the fungus has been present in the past, a repeat application may be necessary at seven to ten day intervals.

Quaking Aspens are such beautiful trees, well-liked because of their leaf flutter in our Central Oregon breezes. Help keep your aspen trees in top-notch shape by preventing the spread of this annoying fungus.

Old ranch buildings and cottonwood trees in autumn color; North Powder River Road, the Elkhorn Scenic Byway, in Baker County, eastern Oregon.