The leaves on your yard’s shade tree that were once bright green and shiny may have been dulled by a common leaf disease called anthracnose.
What to look for:
The disease is caused by a destructive group of fungal pathogens that invade the main leaf vein on deciduous trees. The pathogens produce a distinct fungal spot on a tree’s leaves. Though anthracnose consistently thrives in extended periods of cool wet weather, the affect it has on different trees varies.
Ash trees: brown blotches appear on the leaf’s tips, veins and margins
Maple trees: similarly affected with brown vein lesions originating at the veins and irregular browning of margins that extends inward
Oak Trees: creates large, dead areas between leaf veins
Sycamores: leaf veins and adjacent tissue slowly turn tan and then brown
On all tree varieties, leaf drop can occur if the disease is severe. Additionally, trees may have dead twigs and cankers that result in branch death. Anthracnose generally spreads in infected, dead leaves on the ground. During cold, wet springs, microscopic spores are produced and spread by splashing rain water or wind.
Management & Treatment Options
Management for anthracnose is all about following proper tree care procedure. First, trees should be watered during dry periods. For trees that have experienced leaf drop, rake and dispose of infected leaves then fertilize the tree to help it overcome stress from the disease.
Your local arborist can give you more information about treatment using our slow-release tree fertilizer Arbor Green PRO®. The fertilizer helps improve a tree's resistance to damage from diseases, insects, and stressful weather.
Another important treatment option is selective pruning of dead twigs and branches. Pruning can eliminate the spread of disease to other parts of the tree.