San Antonio Express News
GARDENING, Etc.
Sunday, May 2, 2004

By Nathan Riggs

For years, the Texas Fire Ant Program has advocated the Two Step Method for controlling fire ants in heavily infested lawns and neighborhoods. This method has emerged as a sound, target-specific, cost-effective and time saving way for the average homeowner to deal with fire ants in their own lawn. To this point, most of the insecticides used in this method continue to be very effective, but very few come from natural sources. This week’s article from the Bexar County Extension office will fill you in on some natural ways to deal with fire ants.

For the purposes of clarity, the terms “natural” and “organic” are used in this article to describe pesticides that have natural origins. Natural ingredients that we will discuss today include spinosad, pyrethrins, orange oil, diatomaceous earth and other plant oils.

Sinosad is an ingredient found in several new fire ant baits on the market, one of which is approved for use in vegetable gardens. Spinosad comes from a soil organism and is very powerful against ants, caterpillars, and leaf-feeding beetles. In fire ant baits, spinosad is a powerful ingredient that can kill an entire mound in two to three days after treatment. Organic fire ant baits on the market include Ferti-lome’s “Come and Get It,” Ortho’s Fire Ant Killer Bait Granules, Strike Fire Ant Bait (sold on military bases) and Green Light’s “Fire Ant Control with Conserve.” All of these products do a nice job on fire ants and the Green Light product has the advantage of being approved for application to vegetable gardens. Application to the garden can be as a broadcast or individual mound treatment.

Mound treatments for fire ants in the organic realm include the baits above as well as pyrethrin drenches, orange oil preparations, diatomaceous earth, boiling water and other plant oil products containing cedar oil, thyme oil, clove oil, rosemary oil and others. Pyrethrins and spinosad baits are the most effective mound treatments followed by orange oil, hot water, and trailed further by the remaining plant oils. Diatomaceous earth (DE) is an excellent mound irritant and may kill a few ants, but it usually causes the mound to move. Mixing DE with pyrethrins, orange oil or hot water will increase the kill rate of the ants.

The next best use of these products is to combine them into an organic Two-Step Method. For the first step, broadcast a spinosad fire ant bait at the labeled rate (1/2 to 3/4 cup per 1000 ft) or two to four pounds per acre). For the second step, wait three to five days after broadcasting the bait and treat mounds in the high traffic areas with a fast acting mound treatment such as pyrethrins, hot water or plant oils. Do not treat all mounds with mound treatments, just the ones in sensitive areas. The Two-Step Method is good for heavy infestations and will save money, time and pesticides.

The proliferation of organic fire ant baits has given experts, homeowners and the like, more tools to fight fire ants. As the numbers of folks who prefer natural options to battle fire ants and other insects increase, it seems that industry is trying to step up and find those products on an organic level that actually provide good control. The nice thing is that now all preferences can be satisfied, and there is personal satisfaction to be shared by everyone.

This article was written by Nathan Riggs, Extension Agent-IPM, with Texas Cooperative Extension in Bexar County.