for years my eupatorium gateway have been ravaged with holes in the leaves. for some reason (maybe I dreamed this?)

i thought i had seen slugs doing the damage. but today, i 'undid' the tight clumps of nascent foliage, and there were LITTLE GREEN WORMS. arghhh. do youall know if this is a case for neem's? or something else? by the way, my neems seems to separate from the water and form a coating on the inside of my spray bottle. anyone else? solutions?

thanks much, mindy