I recently found a area of concern on my Osakazuki. My friend is a urban forester for the city of Olympia WA and texted me it might be Sooty Bark Disease? Looks like there have been infections in Acers up in the Seattle area and it could be spreading around the Pacific Northwest. The Sooty Bark Disease might not be 300 miles south yet... hopefully. What are your thoughts on this? The effected branch is showing a late summer flush of new growth, which seems like a good sign.