Die back on Japanese maple clump

[Bonsai Obsessed]

Has any one seen die back like this on Japanese maples? This is an older established clump of standard green maples, trunks are well fused and it was ground growing for 4 yrs. It’s in bonsai soil,and was repotted this spring into its current pot.
Wondering if this is a pathogen that might spread??
Thanks

 

[rockm]

Give this a read:

Read This If You Grow Japanese Maple

This post is about a common bacterial disease called Pseudomonas syringae, which frequently affects Japanese maples yet is relatively easy to control. It is often misidentified as Verticillium wilt…

crataegus.com

 

[Bonsai Obsessed]

Thanks rocks - that looks like the stuff, I’ll start treating it!