Tulip poplar help

[Big Woody]

Hi,

I mostly live on the chainsaw forum but was hoping for some expert opinions. I live in Central KY and the tulip poplar trees on my property are all showing the same signs. Pictures included. Turning yellow and dropping leaves.

Although it is drought conditions most other trees look fine. A number of black walnut trees are also yellowing with brown blotches on the leaves. This tree and other tulip poplars which all look the same have been watered so I am wondering if it is some type of organism causing this (fungus?). There are a lot of brown spots on the leaf bottoms as shown in one of the pictures. I have a backpack mist blower and can apply the necessary chemicals if needed.
What is the cause?

Thanks in advance.

 

[treeseer]

Liriodendron leaves were raining down when I left NC yesterday. No pathogen I can identify; seems that the latesummer leaf drop is just heavier thei year.