Having a prob with the local carterpillars (not the 'soon to be butterfly' type) thinking I'm growing a salad bar for them here... I picked up a bottle of "Green Light lawn & garden spray" which I was informed at the time would do the trick, while at the same time not harming the ferns. Would really prefer to be out the $15 for the bottle than $1500 on the ferns before I give it a go, though... Thanks much all!