Question
My knockouts and a few miniature roses have colorless areas on the back of the leaves in small round and oval patterns.  Within a few days the colorless area is now a hole.  This occurs only in the middle of the leaf not edge or vein area and makes the leaf skeletonized.  This is not Japanese beetles since I am dealing with them also.  A local expert said it was a tiny caterpillar feeding on the back of the leaves and to use bacillus thuringiensis.

Answer
What you are describing are rose slugs. A tiny little worm that looks like a slug and eats from the back of the leaves only the good parts and leaves the hard bits such as the leaves's veins. These bugs eat rose leaves then drop off to the ground and pupate and start the cycle all over again. Take off all the leaves that have the slugs on them and then sray with horticutural oil or Neem oil. Don't forget to spray all around the base of the rose bush. Bacillus thuringiensis is a good non chemical deterrent, but alas, it doesn't work on rose slugs.