Print This Page

Fire Ant Control with Grits

Abamectin is the natural product of a fungus, Streptomyces avermitilis, and is commercially available for killing mites and other insects including but not limited to ants and roaches. See Fire ants or the specific ants you have.

Grits for Ant Control

We have found that corn grits work better than orange oil. Use the regular or quick grits, not the instant grits.

The latter have already been expanded. If in doubt, check the weight on the box and the quick grits will be at least twice as heavy for the same volume as the instant grits.

We find that the quick grits work much better than the orange oil which has the tendency to kill grass. The grits kill all of the ants within 1 to 2 days while the orange oil may not. For that matter, grits works just as fast as most pesticides. But, the ants may come back as they will continue to hatch. In that situation, just apply more grits.

As far as the dried molasses and beneficial nematodes, ours were doing fine until late August. Before then if a mound started, the ants would die out within 3 or 4 days. But, with the hot, dry weather I believe the we have lost some of our nematodes near the surface. Some mounds do die, but some get large and have required the grits.

My wife claims she like to listen to the ants going pop.

David Griffith, Plano

Here is my take on why grits or cornmeal can inhibit Fire Ants.

Fire Ants vary their diet seasonly.  Typically they go after proteins more in the Summer(worms or dead bugs or meats or animal oils, etc.).  In the Fall and Winter, they diet more on carbohydrates.  This is when starches (grains) are more appealing to their diet.
Probably what makes the cornmeal (or the cornmeal nature of grits) more effective in inhibiting Fire Ants is that they feed this to substance to their larvae in order to break it down into a digestible food source for the adult Fire Ants.  Their food source normally is based upon a type of fungal breakdown in concert with their young.  This is inhibited by the cornmeal. The antifungal nature of the cornmeal/grits upsets this feeding cycle where the adults can not obtain their final food product (a fungus-based food secreted via the larvae).  Essentially, the Fire Ants start to starve because their primary food source isn't happening -- it has been "infected" as a result of the antifungal activities of the grits or cornmeal. 
Some of the details of this cycle might be rough around the edges on my rendition, but this is probably why people find success with grits this time of year.  In the summer, grits will probably be less effective.
I am no Scientist, but I do a lot of research along with experimentation in the real world.
Tom Theimer
October 2005

Fire Ant Control Program
Howard Garrett 3/09
<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

Preventative maintenance 

It’s important to understand that first the fire ant issue is a man-made problem.

1. Increase biodiversity. Fire ants are more of a problem in new neighborhoods than in older neighborhoods, where there is a more stabilized ecosystem. When fire ants are forced to compete they become less of a problem. We must do our part to encourage nature.

2. Treating the lawn spring and fall with nematodes. Treat after sunset and follow-up with ½ inch of irrigation. Nematodes are live microscopic worms and need to be applied at the highest recommended rate and in a manor to ensure their survival.

Individual Mound Treatment 
3. Pour the mound drench formula into the center of the viable mounds and apply beneficial nematodes at label directions. Here's the mound drench formula.  Mix equal amounts of compost tea, molasses and orange oil. Use 4-6 ounces of this concentrate per gallon of water and use as a drench to kill fire ants and other pests in the ground. Use a container that pours a solid stream of liquid.   Pour into one spot in the center of the mound. This causes the mix to go quickly to the bottom of the mound where the queens will probably be kept. Then pour the remainder of the mix in a circular pattern covering the entire mound. You might want to save a little to splash those ants trying to run away or worse, up your legs. Rev. 4/10

Large area Treatment Program or Bad Infestations
4. When large areas have bad infestations of fire ants, the next step up from the nematodes and citrus drench is applying baits on the whole property at 1-1/2 lb. per acre and one teaspoon of bait per mound. The baits we recommend are the ones containing abamectin because it is derived from a soil microorganism. At low concentrations abamectin acts as an insect growth regulator and when used on individual mounds it is a stomach poison. Baiting should be done in the spring and fall during times of active ant foraging. Test the timing and the bait’s palpability by applying a small amount to individual mounds and watch for a quick uptake. For mounds along sidewalks, house foundations etc. bait is normally required to get effective control, because the ant colony is protected under the concrete.

5. The next step up from the abamectin baits is the chemical growth regulators. These products do not kill ants, they obstruct their life cycle. This process is slow and should be looked at as a low toxic method to decreasing fire ant populations on large properties over a period of several months. Extinguish is a product that has demonstrated good results. As with most baits it is best used in the spring and fall when ants are actively foraging.

Fire Ant Drench Formula


Homemade Fire Ant Mound Drench - mix one part compost tea, one part molasses, and one part citrus oil concentrate. Mix at 4-6 ounces per gallon of water for treating fire ant mounds.


  Search Library Topics      Search Newspaper Columns