Anthracnose Disease
Anthracnose Disease
Anthracnose is the name of several common fungal diseases that affect the foliage of woody ornamentals in Wisconsin. Trees that are most commonly and severely affected by anthracnose include ash, maple, white oak, sycamore, and walnut. Anthracnose typically affects young leaf tissue.
Symptoms vary from host to host, but in general, include irregular spots, and dead areas on leaves that often follow the veins of the leaves. Affected tissue can vary in color, but is often tan or brown. Severely affected leaves often curl and may fall off. In some tree species, such as sycamore, twigs can also become infected leading to twig dieback.
It is caused by several fungi (many historically classified in the genus Gloeosporium) that survive in leaf litter. These fungi are host specific. The anthracnose fungus that infects one type of tree (e.g., ash) is not the same one that infects another type of tree (e.g., maple). However, when anthracnose occurs on one tree, then weather conditions (typically cool and moist conditions) are favorable for the development of the disease on many types of trees.
For many trees, anthracnose is a cosmetic disease, making a tree look a little ragged, but not killing the tree. However, if a tree has been defoliated by anthracnose for several years, or it is a tree, such as a sycamore, where twig infections can occur, then you may want to use a fungicide for disease control. Three treatments are typically needed for adequate control: one at bud break, one when leaves are half expanded, and one when leaves are fully expanded. Fungicides containing copper, chlorothalonil, or mancozeb are registered for anthracnose control in Wisconsin.
Call Johnson Ops Tree Care at 608 526-6287 our ISA Certified Expert Arborist can help develop a healthy plan for your landscape through our PHC ( Plant Health Care)