I live in the high desert in north Los Angeles county. I have a 15-yr-old silk tree (alibizia julibrissin) which is suddenly dying off in big chunks. A web search leads me to suspect mimosa vascular wilt, although it is not mentioned as being found in California. Any Californian seen this disease?

I'd really like to confirm the problem. Any suggestions on who to talk to or email? My local nurseries have not been very helpful so far.