Fire ants have already been pretty bad this spring, partly because of somewhat wet conditions. Couple that with warmer weather and out pops the fire ant mounds. Fire ants are most active in the spring (and fall, too) when the daytime temperatures are between 70 and 85 degrees, or when the soil temperature is between 65 and 75 degrees.
Active fire ants make mid-April through mid-May a good time to treat and kill them.
Despite my best efforts on educating the public, many people still do not know the best way to control fire ants. Most people (about 80 percent, according to one survey) try to control fire ants by treating individual mounds. Mound treatments are more expensive and require time and labor if you have a lot of land to treat. You can easily use too much insecticide, which may lead to environmental contamination if rain washes the insecticide into lakes and streams.
There are many fire ant control products available at garden centers, but the best is a fire ant bait.
Fire ant baits consist of pesticides on processed corn grits coated with soybean oil. Several baits are on the market, but the one you will find most often in retail garden centers is Amdro. Others that you might see are Award, Ascend, Extinguish, Spectracide Fire Ant Bait, and Pennington Fire Ant Bait.
Treat your yard late in the day when it is dry and rain is not forecast for at least 24 hours after you apply the bait. After the bait is on the ground, actively foraging ants will quickly pick up and carry it into the nest within minutes. If the ants are inactive and don’t find the bait quickly, it will become rancid and no longer appeal to them. Use fresh bait, and apply it by label directions. It doesn’t take much. Usually about one to one and a half pounds per acre is sufficient. Baits should eliminate about 80-95 percent of fire ant mounds for about six months. You should reapply them in the fall during the time frame from about the middle of September to the middle of October.
Baits are by far the most economical option if you have a large yard of perhaps an acre or more.
Many brands of baits fall into two basic groups; those with active ingredients that are toxic to ants (like Amdro) and those that have as active ingredient growth regulators that sterilize the queen and stop development of the immature ants in the colony.
Applied every six months they often carry a guarantee of “no mounds” if applied correctly. It’s not “no ants” but “no mounds.” It takes about six months for a colony of ants to grow from the founding queen to a size where there are enough workers to build the characteristic mound. Baits are good at breaking that cycle. There will be ants between these applications, just not all that many.
For smaller areas, or where you need zero ants, use a broadcast application of a contact insecticide. Examples are those with pyrethroids as active ingredients. Pyrethroids are active ingredients ending in “thrin” such as bifenthrin, permethrin, cypermethrin, or cyfluthrin. There are several of these in the stores. Some include Over ‘n Out, Ortho Max Fire Ant Killer Broadcast, Spectracide Yard Protection, Amdro Fire Strike, and Scotts Snap-Pac Fire Ant Killer all designed for subdivision sized yards. Pyrethroids will provide one to three or even four months of control. After that, the cycle starts over when the ants start flying, which is basically almost year round except for two or three winter months.
Another insecticide that has only been on the market for a few years is indoxacarb, sold as Advion for commercial use and in the Spectracide line (Once & Done) for homeowners. It’s a bait, but instead of weeks to see a reduction in ants, they start to disappear in a couple of days. It’s still a “no mounds” type, but fast acting.
Individual mound treatment products still have their place because many times we need to get rid of a mound immediately because it may be in a high profile, or high traffic area. Probably the best here is the acephate, sold on the retail market as Ortho Fire Ant Killer. This is the one with the “rotten egg” smell. Others you may find in stores are Bayer Advanced Fire Ant Killer, Amdro Fire Strike Mound Treatment, and Bengal Dust Fire Ant Killer. You can also use the Amdro bait as an individual mound treatment, though again, this is not the most economical way to use it.
Several years ago they released phorid flies, native to South America for biological control. They have actually done pretty well and there has been some fire ant reduction. Phorid flies eat the heads off the fire ants. In studies done by Universities, fire ants are scared to death of phorid flies and you can understand why.
There are other “home” remedies for fire ants that people still ask about. One is putting grits on a mound. The idea is the fire ants eat the grits, drink water then explode. The reality is they don’t take solid foods, they chew food up and regurgitate it for the larvae to eat.
Shoveling one mound to the other so they will all fight to the death does not work. And the latest I heard a few years ago, pouring club soda on the mound, does not work either. The ants will simply move.
REACH SID MULLIS, THE DIRECTOR OF THE UNIVERSITY OF GEORGIA EXTENSION SERVICE OFFICE FOR RICHMOND COUNTY, AT (706) 821-2349 OR SMULLIS@UGA.EDU.