you probably have aphids. try using Dr. Earth organic spray... as implied its totally organic, so no chemicals involved; it contains things like clove and cinnamon oils...it actually smells pretty pleasant too! its best to spray around dusk so that you don't burn the plants with the heat of the sun. It's not selective for particular bugs though so make sure not to spray lady bugs or lady bug babies (they're black alligator looking things with orange spots). hope that helps!