actually it looks like a dead 1, when I sprayed my plants that is what the dead 1's look like. If you have a jeweler's Loup or anything that magnifies, look under the leaves of the bottom of the plant cause that's where they start and work their way up, look close in the area that your picture shows, where the leaf starts at the stem and you should see eggs with a few mites crawling around, I can't see clear enough but I think those are eggs going up the stem of that leaf. Captain Jack's is what I use, it's organic and kills on contact, problem is with mites from what I've read is, if you don't get them all the first time they grow a resistance to what your using, a lot of websites I've googled about mites say you should change up on your treatment, like using a bleach solution 1TBSP bleach to 1 gallon of water sprayed on top of leaves and underneath including stems and stalks, spray some on the soil or what ever your using, then next application use 1 part of alcohol to 9 parts water again sprayed, I like using Captain Jacks cause you can add it to the water when watering and kill any that's in your medium. This is how I treat any that pops up, others might have a different way but my mites were gone with in 2 days. Good Luck