Hello,

Based on what I see in your images and the symptoms you’re describing on your maple tree in Michigan—thinning from the top and middle, brown and shriveled petiole stubs with the seed pods still attached, and gall-like bumps on green leaves—could be caused by maple gall mites. These tiny mites feed on the developing leaf tissue, causing the formation of galls as a result of the interaction between the mites’ growth-regulating chemicals and the plant hormones. More information at these links:

Maple Gall Mites (Eriophyidae) – Wisconsin Horticulture

Leaf Galls on Maple (psu.edu)

Insect and mite galls | UMN Extension

Also, the thinning you see in the upper and middle part of the maple tree might be caused when maple petiole borer larvae finish feeding in the petioles of maple leaves, causing the blackened, restricted petiole (leaf stems) to break and the leaf to fall. The stems usually break in a darkened area near the leaf blade. Usually, infestations are limited to sugar maples; only about 25 to 30 percent or less of the leaves fall to the ground. While spectacular, the leaf drop has little effect on tree health. Sometimes, spring storms also cause some maple leaves to drop. The best way to tell why the leaf dropped is to look at where the leaves came from. If you can still see a small petiole stub attached to the tree, it was most likely due to maple petiole borer. However, if the petiole broke cleanly at the base where it is attached to the tree, it was probably due to wind damage. More information is at this link:

My maple tree is dropping leaves, what’s wrong? - MSU Extension

Here’s what you can do:

Treatment: Control is generally not recommended for established trees, as the galls are primarily a cosmetic issue and have little effect on the tree’s see in your health1. However, you might consider handpicking damaged leaves to reduce mite populations for newly planted trees or severe infestations.

Prevention: For extreme cases, preventative treatments in early spring, as the mites begin feeding on expanding leaves but before the galls have enclosed them, may reduce the incidence of galls.

It’s important to note that while these galls may look concerning, they usually do not significantly harm the tree.

If you’re considering treatment, getting a confirmed precise identification and diagnosis of the situation with your maple tree is always a good idea. I highly recommend that you send all your images by e-mail to the MSU Plant & Pest Diagnostics Lab for a precise diagnosis and identification. The experts there can provide you with the best treatment options. Their email is <personal data hidden> - Please include your name – The lab will let you know if they need a sample sent. FYI – The lab may also ask for additional images.

Their website is at this link:

Plant & Pest Diagnostics (msu.edu)

Their Contact Information is at this link:

Contact Us - Plant & Pest Diagnostics (msu.edu)

This link will explain the details of submitting a sample to MSU Plant & Pest Diagnostics Lab:

Submit Samples - Plant & Pest Diagnostics (msu.edu)

Another option is to consult a local arborist for advice tailored to your situation. The arborist would do an onsite evaluation of the maple tree. To find an arborist in your Zip Code, go to this link:

Find an Arborist (treesaregood.org)

I hope this helps!