I have about 6 giant swallowtail butterfly caterpillars on my small orange tree and they are eating all of the new leaves. Should I kill them, or let them be? I love butterflies, but don't want them killing my tree.

Do you have any italian parsley? If so you can move them that and they'll eat until ready to form the chrysallis.

I do, but the plant is very small and I don't think they would survive on it.

well, I feel your pain. I personally don't think they'll kill the tree. Are they pretty large already? If so, they may be a few days away from leaving to find a place to adhere to. If they're still pretty small you may have a week or 2 to deal with them.

go to Lowes or Home Depot, buy up all of their left over fennel and move them to it. My fennel is still covered in catepillars......