Pests

Although it's a little out of focus, I believe your photo shows a lace bug. These insects particularly like eggplant but also feed on tomato and pepper plants. They do have natural enemies such as assassin bugs and spiders, but if the population grows very fast, the predators are slow to catch up. You can use any pesticide labeled safe for vegetables, and there are many organic options like Neem oil and insecticidal soap.