Thanks for all the good ideas!

First I removed all food sources, no dogfood left in the bowl, food scraps laying around, etc.

That helped a bit, but didn't fix the problem totally.

I used slightly more forceful disciplinary measures. He has not showed up since. I'm crossing my fingers but I doubt he will be back. His last visit was slightly traumatic for him. let's just say that while I was "talking" to the dog about the problem he was (LITERALLY) ****tin' himself! He was scattering turds all over the place.