Hello,

This morning I noticed on two of my small maples (Sango Kaku and Aka Kawa Hime) lots of small black spots have appeared on the leaves. I'm including a picture of each. This many must have appeared almost overnight because yesterday I didn't notice them. They're not on every leaf and seem to be mostly on the top most leaves of both trees, but there are some on the lower leaves as well. They can't be rubbed off and look like the leaf itself is damaged.

The other damage to the leaves (dark tips, crispy edges) is how I received them about two weeks ago (one from a garden center and one an online purchase) and is not new.

In doing some research it looks similar to damage caused by aphids, or potentially a fungus? I haven't seen any aphids, but I have noticed a couple little gnats or flies now and then, and have sprayed the leaves with neem oil a couple times since I received them. I did test the neem oil on a few leaves of each tree and it didn't seem to cause a problem, so I'm inclined to think it's not the neem oil itself doing this.

The trees are in containers and are near each other, so if it was a fungus that was already on one of them it could explain why two trees now have it.

I have a few other small trees that may be starting to show a similar pattern of black spots, but not nearly this bad. I've included some pictures of those leaves as well. Again, the other damage (crispy leaves mostly) is how they were received. It's just these spots that are new.

We live near a highway and so I have noticed some dirt/dust buildup on the leaves that I've been brushing off with my hand or spraying off with a water bottle. Not sure if that would cause this.

Does anyone have any suggestions?