Could be sawfly larvae, if so you should find the tiny slug looking things on the leaves. Most any spray should be effective but only if it contacts the insects!

I will take a look for the sawfly larvae as suggested and get my hands on something specific for them if I can positively identify them.

I've attached another picture of the damage for reference.

Thanks.

This post was edited by inv3nt0r on Mon, Aug 4, 14 at 11:10

Japanese beetles like cherry trees. They leave a skeletal pattern on the leaf but some of yours look fully consumed so you might have both Japanese beetles and caterpillars or a larger beetle.

Thanks for the further advice. The Japanese beetles have been wreaking havoc in our area this year, so I wouldn't doubt that they got at the tree.

This particular tree was a little bit yellow following transplant while the others stayed a nice dark green. It looks like the insects are much more damaging to a plant in a weakened state.

From what I've read soapy water isn't effective against the beetles but apparently cedar oil can be used as a natural deterrent. I will try it out and hopefully the plant will come back strong next spring.