Dave I've never had any mite problems or any other insect on my dormant plumies. Maybe the cool temps discourage them? I don't think I've ever had an insect problem during the growing season either come to think of it. Besides my succulents and cacti the plumies are the most insect resistant of my plants.
Karyn

It's just that I thought I read somewhere that black-tip fungus was spread partly by mites and wanted to make sure all my plants are healthy.

I have noted that some cultivars are more suseptable to tip fungus. esp. Lurline.