Russet Mites are extremely damaging to cannabis plants, and can quickly wipe out an entire garden. They are extremely tiny, so small that you can barely see them with a microscope, and they lay their eggs inside the plant so it is hard to get rid of them. Since they are so small, the only way to know if they are there is by the signs your plant shows. The leaves will begin to twist and curl around, and will become very rigid and shiny. This is how you know you have Russet Mites. The best way to prevent them is to keep a sterile grow space, and to not come in contact with them outside.
How to Cure:
There aren't a whole lot of options when it comes to curing this issue. Some recommend spraying with neem oil, but I really try to stay away from that as it is harmful to humans! An all natural and healthy alternative that works just as well is Esentria IC3, and all you have to do is dilute it with water in a spray bottle and then mist is all over your plants right before lights go out. Do this every day, and even after signs of the mites start to go away. The plants may be looking better, but that doesn't mean they are completely gone! Wait at least 2 weeks after completely getting back to health before stopping the spray. If in flower, be sure to avoid spraying the buds as best as possible.
Esentria IC3 Mite & Insect Killer