Will cornmeal deter ants?
:-D Only if you mix the ants and corn meal with some buttermilk and bake it in a 450f oven for 25 - 32 minutes. Then not only will this detrer ants but they turn out delicous as well.
In reality there are many ant baits that use corn meal or hominy grits as a carrier medium to broadcast pesticides targeted at ants.
Mix sevin or maybe gasoline in with the cornmeal and you would do some good getting rid of ants, and anything else that runs into it. I would not try it.
Water, grape jelly and borax in equal parts. Put in a container with small holes so the bees can't get in.