Hi Annie. If you aren't against insecticides, pretty much any garden specific one will do. Make sure you spray the underside of the newly emerging leaves as well as the top and also put some on the ground around the main stem.
If you'd rather go organic, use DE diatomaceous earth. It's inorganic with no toxins .. again dust the undersides of the newly emerging leaves as well as the tops and a bit on the ground.
You do NOT want to use DE on plants that are currently flowering because it will kill the good bugs (pollinators) as well.