Hard to tell from the photos. For aphids, I start by brushing them off with a paintbrush. Second tactic is Safer Soap insecticide (some kinds have pyrethrins and/or neem oil). I give them a dousing with Safer's, then the next day set them outside the greenhouse and spray them with a fine nozzle to wash the wee buggers off.
In a greenhouse ladybugs can be good, especially the second generation, little stripy monsters known as aphid lions.
Had whiteflies a couple years ago: worst ever plague. I had to clean out the greenhouse, burn the dead stuff, and let it freeze up for a month to get rid of them.
