I have a tree fern planted in a pot a few years ago. Lately, I noticed black hairs at the bottom of the stems. The leaves started drying out from the bottom up even though I was watering. Then more recently there are white dots on the leaves. I found on the web that they might be spider mites and I can spray them with a water and rubbing alcohol solution. I will try that. Should I worry about the black hairs? Should I repot the fern?