I bet you thought you were on to something? Well, truth is, grits will NOT kill fire ants.
In the first place, adult ants cannot digest solid foods. Worker ants can be seen going back to their colony with either a swollen belly (from liquid foods) or carrying a solid piece of food. Solids are fed to ant larvae in the nursery; larvae digest the solids and immediately regurgitate the nutrients back to the adult worker ants. These ants, in turn, feed other ants in the colony. On the average, each worker ant will feed 10 other ants. This unique transfer of nutrients insures that any poisons or bad foods are filtered out before reaching the queen and the workers around her.
Second, ants love corn! Many farmers have severely damaged their machinery while running into or over large fireant mounds in the fields. Thousands of pounds of grain products are tossed into the trash by home owners each year, because ants invaded the containers in which grains are stored. Ants love corn and it does not kill them!
The myth with grits (and other grains) began when the general public discovered that small grains of ground corn (in essence, grits!) are the carrier in many ant baits. The carrier is just that - the product on which the attractant (soybean oil, etc.) and the pesticide (Hydramethylnon, etc.) are placed. The carrier is just the vehicle with which we disperse granular pesticides and baits.
When people dump grits or other such objects onto an ant mound, the ants do not appreciate the door of their home being disturbed. They then build another door (mound) to their colony, deserting the one covered with grains. Ants have many uses for their mound (incubating young, etc.) and do not appreciate it when you dump things on top! When all is said and done, the colony did not even move (as most people believe), it just built another doorway to the colony.
This is good to remember when using an ant bait: do not dump the product on top of the ant mound or nest. Instead, broadcast your baits around the mound and in other areas where ants are seen foraging for food.
All this being said, I've found that fire ant killing products containing 70% acephate work best. Just follow instructions on the package for dosage and application method and your fire ants will be gone.