They're white flies. Welcome to the world of outdoor growing! Just ignore them, usually if you don't spray, the predator wasps and hover flies will turn up and eat them anyhow. They won't do too much damage, nothing your plant can't handle, unless they breed up into plague proportions, but his usually only happens because people put out traps or spray/treat their plants with chemicals that kill all the predator insects too. Just as the white flies breed up, so to will the predators of white flies build up and in the end it all balances out into a happy little ecosystem. Any poisonous sprays will just get rid of the predators before they breed up to feast on the white flies, resulting in the white flies breeding uncontrolled. One day you will go outside and if you haven't used any poisons, you will wonder what happened to all the white flies. As insects breed so quickly/have such short lifespans, the predator insects will be 3-4 days behind the white fly bonanza, but in 10-14 days the predators will have won, due to there being more predators than white flies. It is all part of "the web of life" and a balanced ecosystem needs a toxin free zone to be effective in a balanced prey/predator relationship that will sort itself out if left alone to Mother Nature to do her thing. In this case, it IS a case of "ignore it and it WILL go away"!!
Hope this helps,.... Organoman.