In my yard, snails/slugs leave a webbing on the leaf and only damage a portion of it. Katydids eat a portion of new leaves and for the most part they are still on the trees. This is a total strip and I have not seen such unless high winds ripped through. Any chance you had a few really strong gusts of wind lately?

Are you sure your leaves are not just falling off for lack of adequate nutrition?

Not sure. I was wondering if the green around the nodes was chewed there.. Nutrition would be a preferable problem. Thanks. Easily fixed. Is it ok to be fertilizing this late?

I don't see any problem with fertilizing now in your zone. Overall your tree appears to be seriously underfed; and the small size of the fruits tends to support that.

I have found a poorly fed tree to not be able to survive a winter's cold temps as well as a well fed greeeeeen tree. If its nutrition, and it seems it is - then you will want to use an inorganic and now. Forget the organics... they take much too long to be processed by the soil's microorganisms; nutrients would not be available for a month or more. - good luck and post a couple pics with your updates. - George