Fire ants in the south have now exploded following the heavy rains. Here's the updated 3-Step Organic Program that works to control this man-made problem.
1. Treat the site. Apply beneficial nematodes. These are living organisms and must be used before the expiration date and/or before they die in the package. They will also control other insect pests in the soil. The alternative is to apply dry molasses at 20 lbs. per 1000 sq. ft.
2. Drench mounds with the mound drench formula. 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 04/10
3. Go organic and use the entire Basic Program. The biodiversity of microbes, insects and other animals is the long term control.
We have several species of ants in the garden and sometimes in the house. Most of the ants other than fire ants are beneficial in the garden. Some in the house are easier to control than others. If you have the kinds of ants that need controlling, I can help you. There are several non-toxic ant controls that are cost effective and easy to use.
Most ants in the garden are either beneficial or just a nuisance. The three most troublesome in north Texas are odorous ants, fire ants and various carpenter ants. Fire ants are best controlled with mound drenches of citrus-based products. There are now commercial products, but the formula for a homemade version is available here on the web site. Beneficial nematodes and going totally organic is the rest of the fire ant program that really works.
Odorous ants, similar to carpenter ants, are best controlled with Abamectin baits. Sugar ants and other house ants can be controlled in the house with baking soda, cinnamon dust, tansy leaves, citrus oil sprays or baits made from sugar with a little bit of boric acid. My most recent tip is black pepper and it seems to work well. If you have ants and other troublesome insects in the attic – dust with a mix of cinnamon and natural diatomaceous earth. Hot pepper dusts or liquid sprays also work.
Member tip: 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 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.