I have an older non-fruiting crab in my front yard and I think it has apple scab. I just got a new chestnut crab in the back yard and I don't want it to catch anything. The tree in the front is huge, it is not a dwarfed tree. I'd never be able to spray all the leaves with something like neem. Is there something I could use at the root level to help? I think I just need to make sure I rake up all the leaves and burn them to cut down on anything ready to take hold next spring, and then try to keep the leaves protected with the spray.

Has anyone ever successfully rid a big tree of this?