So one random Saturday morning I wake up and there's mushrooms in my lemon tree. I was appalled. Seriously. I promptly plucked them from the pot and told them never to come back. Low and behold about two weeks later they returned. Once again I ripped them out and told them no more. They haven't been back since. But what in the world? How does this happen? And how do I ensure they are never a part of my life again? Any advice?