Excerpts from Steve
Tvedten's book "The Best Control
(Used here with permission.)
Fire ants will usually not build a mound in a shady location. Mounds on clay soils are usually higher than those on sandy soils. There can be 50 - 800 mounds per acre with a combined biomass equal to that of a cow! They move quickly and can relocate their entire colony in less than 24 hours. 75% of fire ant colonies move at least once every 90 days, usually when they are disturbed by vibrations, lawn mowers, traffic, insecticide poisons or repeated flooding either natural or man-made. There are several biological controls for fire ants, e.g., parasitic pyemote mites and parasitic nematodes, e.g., Nc Nematodes. There are at least 18 species of parasitic phorid flies, 3 species of nematodes, 10 or more microorganisms, a parasitic ant, a parasitic wasp and dozens of other symbionts of undetermined importance and/or effectiveness in South America but only 2 - 3 in the U. S. (Collins 1971). That is obviously why the fire ants are 4 - 7 times more abundant here than in South America, When fish eat fire ants, they often die. Whole fire ant colony balls can float in clear water, but sink in soapy or enzyme water and will not cross a sticky barrier. As a last resort use natural diatomaceous earth with pyrethrin, e.g., Perma-Guard® or call 1-800-322-5252 and order Insecto Formula 7 which uses all natural ingredients, e.g., sugar, ammonia and pine oil and is mixed 1 oz. to a gallon and then poured directly on the nest. Try boiling your own brew of soapy water (3 - 4 oz. liquid dish or Kleen Kill® peppermint soap per gallon for a total of 3 - 4 gallons) with or without vitamin C, ascorbic and citric acid, orange juice, pine oil, diluted Kleen Kill® enzymes, citrus oils, sugar, white vinegar and/or ammonia and pour the mixture on each nest in the yard; repeat daily as needed. The oils in citrus peels are very effective on ants that contact them - but they break down quickly, so copiously flood the nests with them.
Baits. You can broadcast freshly processed corn cob grits coated with soybean oil with 1% borax as a homemade bait in the spring and the fall, especially when no mounds are visible. If you bait in summer, bait in the late afternoon or at night. Use about 1 - 2 oz. per 1,000 square feet. The ants will find the grits and extract the toxic oil for food. Prebait with potato chips to see where to place the baits. If you have a mound, bait around the mound up to 3 feet away (or in a bait container) rather than broadcast the baits. Do not put bait on top of the mound, unless you open it up first and wait 8 minutes. 10% sugar and 1% boric acid or borax liquid baits may eventually work but the control may take 3 - 4 months to obtain control. You can try sprinkling 1/2 cup of dry instant grits on each dry mound. Try using a sweet bait (10%) with soybean oil (87%) and Kleen Kill® (3%) soaked into corn cob grits or pieces of sponge. Try sliced raw fish soaked in a 5% - 10% boric acid acid bath for 10 minutes. Do not apply baits if the ants are not actively foraging.
Dusts. If you are digging up a mound, dust the bucket and/or shovel with baby powder containing talc to keep fire ants from climbing up. You can also dust the nest and surrounding area with talcum powder or medicated body powder to control fire ants or keep them for entering an area or electrical device or building or bee hive, etc. In a pinch, cover the mound with fire wood ash.
(Web Mistress Note: A little license was taken with title and some emphasis. However, the content is correct as it appears in "The Best Control)