While I've never had a problem with the pesky little buggers, I found this recipe in my backyard garden book;
4-5 tbsp of cornmeal
3 tbsp of bacon grease
3 tbsp of baking powder
3 packages of baker's yeast
Mix the cornmeal and bacon grease into a paste, then add the baking powder and yeast. Dab the gooey mix on the sides of jar lids, and set them near the anthills/problem areas.
Hope your parents are successful NoahGrey!