Is my maple tree in trouble?

October 5, 2017 7:41 PM

My maple tree, located in northern Ohio, is looking odd, having developed large dark spots on most of its leaves. I've never seen this before. Is this a sign of disease?
posted by rdauphin to Home & Garden (6 answers total)

Probably tar spot. It's fine.
posted by evilmomlady at 7:48 PM on October 5, 2017 [1 favorite]

Best answer: Your photo is a little blurry on my phone but it looks like tar spots. I am an arborist, I am not your arborist, etc. No need to worry, it happens occasionally to the leaves in late summer or early fall. It will only affect the leaves and won't harm the health of your tree.
posted by snowysoul at 8:29 PM on October 5, 2017 [1 favorite]

Yes it's a sign of disease: patterned spots like that are a clear tell.

But fortunately evilmomlady is probably right and this is a mostly cosmetic disease.

In addition to the remedies suggested in that link, you can try to thin out both that tree and the surrounding vegetation -increased air circulation helps ward off many light fungal pathogens, in part because it decreases the highly local humidity around the leaf surfaces.
posted by SaltySalticid at 8:30 PM on October 5, 2017

Just as a data point, this happened to most of the trees around me this year in Southern Vermont. It hasn't happened before in the 5+ years we've lived here.
posted by Betelgeuse at 3:57 AM on October 6, 2017 [1 favorite]

My maples did that about 5-7 years ago. It is a fungal infection, it didn't kill the trees and they are OK now but the spots showed up a few years in a row. It didn't kill my trees. I have read that the only thing you can do is keep the fallen leaves raked so it lessens the chance of reinfecting the trees year after year.
posted by waving at 5:30 AM on October 6, 2017

It's happened everywhere in MA this year. It's tar spot and it's mostly due to the really wet spring we had. Worry not, it's just cosmetic and the trees ought to be just fine next year.
posted by lydhre at 7:39 AM on October 6, 2017