Maple Trees infestation black spots

Asked June 4, 2020, 1:50 PM EDT

My area of MI seems to be experiencing maple tree fungus, and I can't tell if it is tar spot or the more serious deadly one (anthro something). Tree people are backed up so I can't get anyone out here to look at them. Any suggestions for how I could differentiate and know if I do the right thing by simply raking up the curled, black-spotted leaves (should they be burned)?

Ottawa County Michigan

1 Response

It's early for maple tar spot to be showing; this fungal disease doesn't emerge right away, but are typically obvious by mid to late summer.

It is likely your maple trees are infected the maple anthracnose. Anthracnose
can be a fairly common spring disease on maple leaves in some years, and this looks like one of those years.

Anthracnose affects newly emerged leaves. The frequent spring rains we experienced this year coincided with leafing out on maples and they are now heavily infected with maple anthracnose. 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.

Otherwise healthy maples can withstand this disease. Sanitation is the most important thing you can do to reduce the fungal spread. Rake up and destroy the fallen leave if possible. Do not compost them. The information in the link below will give you additional information: