To whom it may concern, We live in Fennville, Michigan. We purchased this Autumn Blaze maple tree from a local nursery 4 years ago. We planted it in our front yard which faces south. We do have sandy soil. The tree did develop some tar spots the past two years. This year though, the leaves are already wilting and have different black spot and some with raised red spots. The trunk also develop a green fungus like substance. I have attached a few picture. Is there something going around that is effecting maples? Looking to see if you know what it could be and it see how to treat it. Any help would be appreciated. Thank you in advance. Kristin Doornbos
Maple anthracnose has been a common occurrence this year. Anthracnose can be a fairly common spring disease on maple leaves in some years. There are several different fungi that cause anthracnose. One of the fungi (Kabatiella) causes newly developing leaves to shrivel and turn black, while older leaves develop dark brown lesions along the leaf veins. Fungal leaf diseases do not often threaten the long term health of the tree, but can be severe under certain conditions. Wet springs, and much of Michigan has seen a wet spring this year, usually cause increases of fungal diseases. Read more here: https://ag.umass.edu/landscape/fact-sheets/maple-anthracnose
The "green fungus like substance" on the trunk are actually lichens that commonly will grow on just about any surface under the right conditions, but are harmless to trees. Read more here: https://www.canr.msu.edu/news/what-s-that-growing-on-my-tree
Thank you for your quick response. The provided information was very helpful. The article mentioned spraying the tree with a copper hydroxide + mancozeb, The first application should be made at or just before bud break to protect new growth from initial infection in spring. Is it okay to spray the tree with that now or would it be best to wait til next spring when its starting to bud?
To spray now would be of no help. When the buds are swollen and begin to peek out come spring would be the optimum time. This is assuming maple anthracnose is indeed the correct diagnosis, which we can't make from this vantage point. For that you could send a sample to Diagnostic Services for a small fee. https://www.canr.msu.edu/pestid/
Or you could involve a Certified Arborist, one who specializes in these matters. Find one or more Certified Arborists in your zip code at www.treesaregood.org Go to the Find an Arborist tab. Arborist evaluations are not expensive and where you can learn exactly what is going on in your tree. Plus he/she will be qualified to handle the timely treatment complications as well, if desired.