Natural treatment for Rhizosphaera?

[TreeHgr7]

Hello:

I'm searching for a natural treatment for Rhizosphaera on Colorado Blue Spruce trees. Yes, I'm aware of chlorothalonil, copper hydroxide or mancozeb, but I'm looking for something less toxic.

Would Neem Oil be a possibility? I'm also trying to control bagworms on those trees. I found a product by Bonide called Captain Jack's Neem Max -- it's advertised as a fungicide and insecticide. Would something like that work?

Thanks for your help