You can buy cornmeal at any grocery store.Unfortunately I must take that idea with a grain of salt since the borers are offspring of a moth that lays its eggs on the plant.A friend of mine uses pesticides(diazinon maybe) to keep them off his corn and he says that it kills the ones inside too but I am afraid that such strong chems would kill the users of the finish product as well.I think that using neem oil on a weekly regiment during the entire veg cycle next year will help.Maybe I will even use it biweekly for the early stages of flowering too.Whatever it is he uses he mixes 3 ounces to spray an acre of corn so I figure 1 tsp will do my entire area after harvest this fall in order to do some preventative.