Re: Nosema symptoms
I've read (don't remember where) that Nosema M. leaves poop but that Nosema C. does not leave poop stains.
Dwindling, queen supercedures, dead bees in pile on bottom board, refusal to eat syrup or excessive drowning in syrup. All symtoms I've heard, or felt myself from limited scientific info, were from Nosema C.
Doesn't mean that something else might have some or all of the same symptoms. Best way to know for sure is to send samples in for testing.
20+ years, raise my own queens, feed when needed. I treat, but have not perfected varroa management yet.