fungi

I have 2 young oak trees planted 2 years ago. I was told this year Oak wilt is in the area. Looking at my trees today, both Red Oak and Pin Oak show leaf changes. I am curious if this is what oak wilt looks like or another problem or just normal for time of year. If there is a treatment...

I attached a few pictures for reference, but the bark on the lower trunk is starting to rot and separate/fall off. There seems to be a dark stain behind part of the section that is coming off and also a small section of the wood (left side of dark spot) is starting to rot some on the surface...