Posted on Fri, May. 09, 2008

-- Oh, to live in Australia. In what they hope is their final push to eradicate fire ants from their country, the folks from Down Under are offering a $500 (roughly $473 in U.S. dollars) bounty for anyone who finds and reports a fire ant mound. If they're lucky, the land of Oz may be the first country to rid itself of this pest.

Fire ants arrived in Brisbane, Queensland, about a decade ago and the Aussies launched a well-thought-out campaign to eliminate them.

They've done a good job so far, but there are still a few isolated colonies here and about (they were still finding them as of April 30) so the Biosecurity Queensland people came up with the reward program as a way to finally wipe out the ants. I wish them luck. They have an excellent shot at it.

We, on the other hand, have no possibility of getting rid of imported fire ants here in the U.S. Our choices for widespread control are limited, and we'll just have to learn to live with them. At least, up to a point. Fortunately, fire ants can be controlled within a given area.

There have even been some communitywide efforts that have proven successful, most notably in the appropriately named city of Moundsville, Ala. For the typical homeowner, there are three methods that have proven themselves over the years and are relatively easy and safe to use.

The first is rather labor-intensive and is limited in scope. It has one positive aspect the other two don't have - instant gratification. Mix any liquid or water-soluble insecticide in a bucket of water at the lowest rate on the label and pour a quantity sufficient to saturate the mound.

Depending on what chemical you use, the ants will be dead within five to 60 minutes.

The second method is much slower but is very safe and very inexpensive. There are a number of baits out there, most a form of Amdro.

Amdro contains a stomach poison called hydromethylon. Baits work because of the way fire ants eat. The ants consume almost nothing but liquids. The active ingredient is suspended in soybean oil which is then coated onto a pregelled corn grit. The ants pick up the grit and remove the oil.

Once the ant has fed, it regurgitates the fluid and feeds it to the next ant down the line.

Eventually, the poison is passed throughout the colony and it dies. This time of year, most colonies will be eliminated within three weeks of the application. During colder periods, or when the ants have access to more food than normal, the time it takes for the active ingredient to work can lengthen to up to three months.

There are two drawbacks to baits. First, the baits are designed to go out at a rate of 1.5 pounds per acre. Unless you have a spreader specifically designed to put out fire ant bait, it is very difficult to apply at that rate. With your typical small whirlybird-type spreader, you have to set the opening to as narrow a gap as you can, turn the handle very slowly and walk really fast.

Some companies, recognizing this difficulty, have reformulated their bait so you have a larger amount to put out per acre. This makes it more practical but somewhat more costly.

The second drawback is the lack of residual effect. The bait will kill only the colonies that were there at the time of application. The bait itself is usually taken up by the ants within two to four hours after it hits the ground and any missed granules will be quickly degraded by sunlight and moisture.

The third method is initially more expensive. A product on the market called Over-And-Out will control fire ant mounds in the treated area for up to a year with just one application.

Like the baits, it takes around three weeks for all of the colonies to die. But, unlike baits, it's going to be around for a long time. If applied according to the label directions, you will be fire ant free for the entire year. Prorated over twelve months, the cost of Over-And-Out matches up well with the other two methods.

Ideally, you should use a combination of a bait or the Over-And-Out along with the drench treatment. This two-step approach will give you the best bang for the buck. The use of the bait or the Over-And-Out will eventually result in the demise of all the mounds within the treatment area... even the those you don't know about or can't reach.

Meanwhile, the drench method can be applied to those colonies you have to get rid of quickly - the one next to the air conditioner or where pets or children are active, for instance.

No matter your choice, make certain you read and follow the label directions carefully.

Tim Lockley is a specialist in entomology (the study of insects) and is retired from a 30-year career as a research scientist for the U.S. Department of Agriculture. To have him answer your individual questions, please send a stamped, self-addressed envel