Question
I have 3 crabapple trees and all have lost the majority of their leaves to something that has eaten them. The stems are left on the branches. I have read you advice to other questions concerning the crab apple and I don't see any insects on the tree at this time. No caterpillars or nests or webs. Has whatever ate the leaves(presumably caterpillars) left and I don't need to spray the trees or should I spray with insecticide for the insects coming from another area or tree.

Answer
Anne:
Bugs aren't my best suit, but it would be best to try to find some of these critters, get them ID'd so you can select the most appropriate insecticide. Some materials are better than others for specific insects (they can be costly too) so you want to get and use the best for that insect.  If you can collect a few in a jar or other suitable container, get them to a garden center or your county Extension office to get them identified, then spray the material on the tree as soon as you see some activity.  Be sure to rake/destroy any fallen leaves first and for sure before spring since some of these bugs may spend the winter on that leaf/stem trash.