I'd start by just picking them off, smushing them with your fingers. I think the Malathion should do the rest. Just be sure to get the stems too. And remember that Malathion is nasty stuff not great for the environment so use it sparingly and efficiently.
You could also put something sticky around the stem base to keep them from climbing up it. Once they hit their full growth they'll outgrow any damage the scales can do.
You could also put something sticky around the stem base to keep them from climbing up it. Once they hit their full growth they'll outgrow any damage the scales can do.