Maple Anthracnose

Maple anthracnose can be a pretty common spring disease on maple trees in certain years. Cool, wet weather produces more anthracnose than warmer, drier weather. It is usually a minor disease and doesn’t cause permanent damage to established trees. However, consecutive years of defoliation can weaken the tree and make it more susceptible to other pests that may further harm or damage the tree.

Newly emerged foliage is more susceptible to anthracnose. Symptoms vary by host and by the fungal pathogen present but are characterized by irregularly-shaped, angular spots or blotches that occur primarily along the midrib, primary veins and leaf margins. The lower branches and branches in the interior of the tree are usually infected more than the upper part of the crown. Generally, in large well established healthy trees, a new set of leaves grows to replace those that fall off.

Infected leaves are the primary source, and they should be raked up and destroyed because the pathogen remains viable on the dead foliage even through winter. Remove infected twigs through proper pruning. This will increase light penetration and improve air circulation throughout the canopy. Maintain the tree’s health with adequate fertilization to provide readily available nutrients to the tree. During periods of drought, make sure the tree has enough water.

Consult with a Branch Tree Service ISA Certified Arborists about other possible treatments and options.

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