Oak problems?

[ATH]

This has been a summer of mystery for me. Several unsolved issues. This is the latest, so I'll start here.

35" dbh Red oak

Browning at the ends of some twigs.

There is Kermes scale.

Also Powdery mildew on the under surface of the leaves.

But here is what I am unsure of...there is blackening (necrotic tissue) on all of the twigs that are dying back. It isn't well associated with locations of Kermes scale. I know Kermes can cause flagging as seen here, but looking at the twigs, the blackening doesn't follow the pattern of the scale well enough to blame it on them.

 

[ATH]

PS: necrotic spots are neither raised nor sunken. Maybe a little narrower since the tissue has dried out. Generally each spot goes all the way around the twig.

 

[Raintree]

More Bot canker same as your maple causes twig necrosis on oak. Often found on malus with branch die back this time of the year.
http://www.hfrr.ksu.edu/doc2938.ashx

 

[ATH]

That looks like it! Very nice factsheet with concise information. I had that bookmarked in Sinclair and Lyon, but couldn't convince myself that was it as a few of the close-up pictures don't quite fit.

Thanks!