What type of caterpillars are we talking about? Are they the tent caterpillars?

Certain if not most caterpillars hatch from egg sacks which are deposited by the adult moths up in tree branches so sticky tapes placed on the lower trunk won't be of much help for these cats.

Organic spray like MONTEREY GARDEN INSECT SPRAY with SPINOSAD, should take care of the caterillars.

Moses

Bt, Bacillus thuringiensis, is the standard recommendation for caterpillar control. It is considered completely organic, safe to use around kids or pets and targets only caterpillars. It need to be applied as soon as you see the cats feeding on the foliage.

Sticky traps will not work on cats :-) But if these are tent caterpillars, clipping or pruning out the tents as soon as you see them, then destroying them is also effective. But regardless of method or product, if the trees are large, control will be spotty or sporadic unless you can spray ALL the leaves or clip out ALL the tents.

Ubro: I am really not sure which kind of caterpillars they are.

vgkg: That kind of sucks if that's the case.

Moses: Thank you I will check into that. Is this something that you just spray around the tree trunk or the whole tree. I have really tall oaks too so will not be able to reach any leaves.

Gardenangel: Thank you and I will check your recommendation out as well. Same question, do you spray just the trunk or the whole tree? I just remember seeing them climbing up the trees in numbers. My father wrapped the tree and there were a lot that crawled right up to it and wouldn't go any further. So they had to be coming from below.

I am really not liking the idea of spraying. If I was to use petroleum jelly on some kind of wrap around the tree, will it hurt the tree when it rains on the jelly, like would any toxins drip down out of the jelly?