It could be mites, but it doesn't look like the symptoms I've seen when my plants get mites. Usually the leaves get small brown spots on them and the edges of the petiole brown.
As GrowinOld says, get a loupe or a magnifying glass. If you don't have any vision problems, you should be able to see them crawling around on the leaves.
For treating mites, I use Avid miticide. It seems to work well, but it's expensive. Other options are neem oil, Orethenex (by Orthene) and spraying with cold water regularly. None of these other options seem to eradicate mites though, which is why I resorted to a heavy duty miticide.