Peach Tree

20110608-105921.jpg

QUESTION: Hi all, just wondering if anyone knows what might be causing these little holes in the leaves of my peach tree? Would this be the work of snails, slugs, or some other little bug? I’ve already been treating the tree with a copper fungicide (not as frequently as the recommended five days but more like every 7-10 days for the last few weeks).  Should I continue?  Should I stop?  Should I do something else?