I went out today to turn the horse manure that is in my raised beds. It's been in since mid summer composting with no problems. But today I turned up some strange looking fungus things. We did have our only rain this winter about two weeks ago. The boxes don't seem overly wet. Not sure if they are harmful or what I should do with them. Do you think I should cover beds with black plastic to try and kill it? Should I be worried?