Maple tree issue.

[A. Lyric]

I rake up maple leaves every fall to put on my garden. This year some of the leaves have big, black,
spots that are raised and look like tar. Per Google, I think it might be “black spot disease”.

Does this mean the leaves aren't safe for my garden even though they are dead? Also, does anyone know what causes this disease, how it affects the tree long term, and if it will reappear next year? I have photos if that would help.

Your thoughts and input very much appreciated! Thank you!!

 

[A. Lyric]

Do I have spinach in my teeth?

 

[cpp gardener]

No, no spinach that I can see.
Tar spot is a fungus that affects Maples and causes cosmetic damage. It won’t kill or seriously affect the tree. It’s best to remove and/or destroy the leaves to avoid spreading the disease spores.

 

[A. Lyric]

No, no spinach that I can see.

Tar spot is a fungus that affects Maples and causes cosmetic damage. It won’t kill or seriously affect the tree. It’s best to remove and/or destroy the leaves to avoid spreading the disease spores.

Thank you! I have several vegetable containers not far from the Maple and have been picking off random Maple leaves that have blown
onto them, in an effort to be on the safe side. Per your response, I can see that as time well spent?

This forum baffles me. I'm a somewhat inept, needy, relatively new gardener and come here to learn and ask questions. It's a curious
and dismaying thing for your question to sit unanswered for two weeks. That makes you my hero!

Thank you X 10!!

 

[cpp gardener]

It only affects Maples and is wind borne, so minor sanitation doesn’t have much affect on the vegetables.

 

[A. Lyric]

It only affects Maples and is wind borne, so minor sanitation doesn’t have much affect on the vegetables.

My containers no longer have vegetables growing in them. On impulse, I threw some cover crop seeds in them, although I'm not sure that was a good idea. I just pluck out any maple leaves that fall into the containers because I have "plant disease paranoia" essentially
due to ignorance. I'm happy to know this particular disease only affects Maples! It's pretty "scary" looking.

Again...thank you.

 

[Steve @ Celtic Farm]

Using leaves with black spot disease (likely a fungal issue like Rhytisma acerinum, which commonly affects maples) as mulch in your garden isn't recommended. The concern is that the fungal spores can survive the winter and infect susceptible plants next season.

Black spot disease in leaves is caused by fungi that thrive in wet, humid conditions. It usually doesn't cause serious harm to established trees but can be unsightly and may lead to early leaf drop. Good sanitation practices, like raking up and disposing of infected leaves, can help control the spread.

The disease could reappear next year, especially if the conditions remain the same. To help prevent recurrence, ensure good air circulation around your trees and try to keep the leaves dry (though this can be difficult with weather conditions).

 

[A. Lyric]

To address your concerns, it's best not to use the leaves with black spot disease in your garden, as the fungus can survive the winter and potentially affect your plants next season. The disease is caused by a fungus that thrives in wet conditions and can recur if the leaves are not properly disposed of. It's not typically fatal to trees but can weaken them. For long-term management, improving air circulation and practicing good sanitation by removing and destroying affected leaves can help. If you have photos, consulting a local extension office or a plant pathology expert could provide more specific advice.

I haven't put them in my garden this year, and have tried to pick out the random Maples leaves that have blown into my containers.
I'm fairly confident it is black spot disease as I've compared my photos to photos online. It is a particularly unsightly disease! Hopefully, it's not as damaging as appearance might suggest. Thank you so much for your input. I appreciate it!

 

[A. Lyric]

The disease could reappear next year, especially if the conditions remain the same. To help prevent recurrence, ensure good air circulation around your trees and try to keep the leaves dry (though this can be difficult with weather conditions).

I hope, of course, that it doesn't reappear, but it's often a hot, humid summer here. Ensuring good air circulation and trying to keep the leaves dry seems an impossible task, actually, so I will just have to hope for the best. I appreciate you taking the time to share your thoughts!