Get a rat terrier the big kind. Ours has killed them twice her size.....but other than that here are a few other suggestions. Or use all of them...
Radio in the corn patch
Electric fence around corn patch
chicken wire around corn patch
Walk around the corn patch after the dew has settled
Did I mention get a rat terrier the decker kind..(big ones)
lol Good luck those rascals seem to know when that corn it best.