RE: How to deal with others baiting?
Deer and turkeys may not be taken with the use of dogs, bait, recorded calls or live decoys. Scents and minerals, including salt, are not considered bait. An area is considered baited for 10 days even after complete removal of the bait. It is illegal to place bait in a way that causes others to be in violation of the baiting rule. Mo. Rules.
I'd call the division and ask them how far you have to be.
Tell the owner the guy is poaching and making it ilegal for you to hunt your stand
Move your stand.
Put moth balls on his bait pile with a warning that he will it is illegal to bait.