I live in Montana and have an older jade houseplant. I noticed today that one of the 2-inch thick stems was completely rotted. When I pulled it off, it was infested with these little worms. There are a few black gnats flying around, but not many. And I also see a few very small white bugs that do not fly (mites?). I've attached a photo of the worms. There were seemingly hundreds of them living in this stem and they had composted the entire 2-inch thick (8-inch tall) stem. Any suggestions for how to get rid of them, or what they are?