Well, he's kind of a cute little guy but I bet you don't thinks so right now
Maybe an inch worm . . . whatever the case, he is a caterpillar so a caterpillar spray should work on him and the others that are still so small they can hardly be found.
Bt (Thuricide) is a caterpillar spray. So is Spinosad.
He is so tiny &, maybe, tender - a soap spray might work on him and his brothers. Remember however that any spray may damage the plants that it is used on. Dish soap is made to wash dishes. I will use it on sunflowers and things but for plants that I am more cautious about, insecticidal soap seems a better choice.
Besides, we usually go after aphids rather than the other bugs, with a soap.
We are each other's harvest; we are each other's business; we are each other's magnitude and bond. ~ Gwendolyn Brooks