What is causing yellow spots with 'hair growth' on leaves?

[mjbeller]

I've slowly been bringing this tree (I believe it's a form of crab apple tree) back from some devastating summers and winters about 5 years ago where several large branches died. I've been diligent about pruning and feeding since then.

For lack of a better description, the leaves now have holes along the edges, burn marks, and yellow spots that have "hair-like" growth on the underside.

We live outside New York City on Long Island if that matters.

Here are some pictures in addition to the photo below: https://imgur.com/a/hMj5f#0

Thank you for your help.

[applestar]

This is cedar-apple rust. It's a fungus that alternates hosts between apple family and cedar family. It appears as yellowish spots and then grows spore releasing orange tendrils (the spots turn orange and raised bump) The spore is also orange. Ones like in the picture have already released their spores. So if you have a cedar nearby, it will be very difficult to eliminate the problem altogether.

Trees have varying degree of resistance. Some will not survive too many full-on infection. My Enterprise apple is super resistant and will have some of the spots and spore releasing bodies, but will not be severely affected even without treatment. But I try to cut off and dispose of infected leaves. How badly is your tree affected?

I also typically spray with milk solution and AACT BEFORE HUMID SEASON STARTS. (I didn't this year though). My wild crabapple is more susceptible, and I didn't consider the consequences when I planted a service berry near it. The service berry fruits are ruined by the CA rust every year, though the foliage seems to be resistant.

BTw the holes along the leaf edges are probably something else. Disease pressure/stress makes the tree more vulnerable and attractive to pests.

[mjbeller]

Thanks applestar.

I would say the problem is pervasive throughout the entire tree. I just went and double checked and it's really everywhere. I do believe one of the other trees in our yard is a cedar.

I also think the holes along leaf edges appear throughout most of the tree.

Do you recommend any treatment? Will the tree survive and ever flower again?