Garden Pests and Diseases: Something's killing my sedum, 1 by winging

winging wrote:
This is the third year that one or more of the 'Autumn Joy' sedum I have has died. I thought it was crown or root rot, and I've replaced the lost ones the last two years. This year, I happened to have the camera out when the lighting was just right, and look what I found! Bleah. What are these nasty thing, and how do I get rid of them? This year all the remaining sedum seem to be affected, not just one or two as in the past. Do I have to yank them all?

I guess I'm asking, "Can this sedum be saved?"

Thanks in advance for any help.