a preventative measure would be making some homemade pepper spray from three jalapenos and 2 cups of water in a blender. Let the jalapeno water sit for 24 hours then strain out the water into a container and mix that with 1 quart of water... at this point you can spray on the leaves once or twice a week.
Doesn't kill spider mites but acts as an irritant/repellant and is organic so it doesn't hurt your smoke
-pot