Make sure you have spider mites before you attempt a treatment.
Could also be leaf-irritation from other leaves rubbing against it.
-or-
It could be splashes of nutrient solution left to sit on the leaf.

I'm not disagreeing with the spider mite hypothesis, but make damn sure before you start adding bug poison to your schedule. If you are forced to go the insecticide route, do not let it sit on the leaves, as the crap clogs the leaf stoma which prevents gaseous interchange. (stops respiration - suffocates the plant)

The claw is usually from ph issues, being rootbound and sometimes from overwatering.
Rusty Trichome Reviewed by Rusty Trichome on . Leaf Spotting: Your Diagnosis? Any diagnosis on this spotting on the leaf? There are about 4 of these leaves on one plant, mid-plant. Here's the link to the high resolution pic: FileDen.com | Free file hosting and online storage The grow details are below. TIA for any ideas! ~jessie Rating: 5