Lori, first off you called out the wrong username so someone out there might be confused. But back to the topic...the most common Monarch disease is called OE (for short). Here's a Monarch Watch article about it:
http://www.monarchwatch.org/bi...
Plus, caterpillars get parasatized a lot and there are other, lesser known diseases. I have a Cloudless Sulphur chrysalis right now that instead of turning yellow is turning black. Has a funny smell, too which is pretty much a sign it is not okay. It's a bummer, but it happens.
