Submitted t Journal Of Agricultural And Urban Entomology
Publication Acceptance Date: October 22, 2002
Publication Date: July 1, 2003
Interpretive Summary: Experiments were conducted to determine efficacy of raw citrus peel extract, a commercial citrus oil product, and a homemade recipe for fire ant control. The homemade recipe (equal parts citrus peel extract, compost tea, and cattlemen's molasses mixed with water at 6 oz per gallon), raw citrus peel extract premixed with water, and diazinon formulations performed similarly, though diazinon yielded slightly faster control. Results indicate that viable "organic" alternatives are available for use as mound drenches against imported fire ants.
Technical Abstract: Experiments were conducted in Alabama, Oklahoma and Texas to assess efficacy of raw citrus peel extract (orange oil) (Erath Earth Orange Oil, Erath Earth Holding Company, Erath, TX). A homemade recipe containing orange oil [equal parts orange oil, cattlemen's molasses, and compost tea at 47 ml L-1 water (6 oz gal- 1)], orange oil premixed with water to form an emulsion, and the commercial product all resulted in 80% or greater control when applied in 3.8 L (1 gal) water as a mound drench. In most trials, the level of activity in mounds receiving citrus oil alternatives was statistically comparable to conventional diazinon formulations. Citrus oil alone presented mixing problems prior to application; some possible solutions are discussed. Citrus oil formulations and commercial products appear to be viable alternatives for people who do not wish to apply conventional insecticides against S. invicta.
Itís 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 Ĺ 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. Treat individual mounds with 1-1/2 ounces of citrus and a few drops of soap as a wetting agent per gallon of water. Treat each mound with one gallon of diluted mixture.
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 baitís 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.