Fall Treatment of Fire Ants is Effective
Collectively, ants are beneficial insects in our environment. Their nest-building activities reduce soil compaction and help to aerate the soil. Many ant species are omnivorous—eating just about anything including pest insects and other arthropods. They can actually help to reduce tick and mite populations in our landscape.
However, fire ants can be a curse to gardeners and anyone who enjoys the outdoors. Thousands of fire ants live in just one fire ant nest. If a mound is disturbed, hundreds of ants immediately rush out, climb on whatever disturbed them, and sting. Multiple stings can lead to severe and painful reactions.
So, how can you tell if your ants are fire ants? First, look at the mound. The mound has no opening in the center like most ant mounds. Imported fire ants leave and enter the mound through underground tunnels. Next, look at the ant. Fire ants are small, only about 1/8 to 1/4-inch long. Variation in size is a distinguishing feature. Many other ant species are uniform in size. Then, look at their behavior. They have an aggressive nature compared to other ant species. If a mound is disturbed, usually hundreds of fire ant workers will swarm out and run up vertical surfaces to sting.
Fire ant mounds no not have an obvious opening at the top (left) where other ant mounds do have an obvious opening (right)
Photo credits: Theresa Friday
According to Dan Suiter, a Cooperative Extension entomologist with the University of Georgia College of Agricultural and Environmental Sciences, fire ants are easier to kill in the fall for four main reasons.
First, they're more active. That makes it easier to treat them with fire ant baits. You can use fire ant baits any time of the year, but they're most effective when the ants are actively foraging for food. Fire ants are most active in spring and fall, when daytime temperatures are between 70 and 85 degrees F.
A “bait” is a product that contains slow-acting toxicants dissolved in oil. The oil acts as a food source for fire ants. The ants either carry the bait back to the colony and extract the toxic oil within the mound, or extract the toxic oil immediately and carry it back to the colony internally. The slow action of the toxicants allows the ants to feed the toxic oil to other members of the colony before they die. When the toxicant is fed to the queen, she either dies or no longer produces new workers and the colony will eventually die.
Second, in the cooler weather of fall, fire ants aren't too deep in the ground. That makes them easier to kill with a mound-drench, granular, dust or aerosol contact insecticide. When you use those products, it’s critical to treat when the queen and brood are close to the surface.
Third, in the fall, you're treating when many fire ant colonies are very young. Fire ants mate all year long, but they’re most actively mating in the spring. Mated queens fly away and establish new colonies. By fall, these colonies are well-established but still fairly small.
Fourth, and the one thing that makes fall the single best time to treat fire ants, is that it's followed by winter. Extreme cold is tough on fire ants. This makes baits even more effective in the fall.
For more information on “Imported Fire Ants in Lawns and Turf” visit the University of Florida publication at http://edis.ifas.ufl.edu/lh059 or call your local extension office.
Contact Information
For further information and to register contact Theresa Friday by phone at 850-623-3868 or e-mail at theresaf@santarosa.fl.gov.
The use of trade names, if used in this article, is solely for the purpose of providing specific information. It is not a guarantee, warranty, or endorsement of the product name(s) and does not signify that they are approved to the exclusion of others.
For more information or if you have a question, call The University of Florida/IFAS-Santa Rosa County Extension, at 850-623-3868, between the hours of 8:00 am and 4:30 pm weekdays. Hearing-impaired individuals may call Santa Rosa County Emergency Management Service at 983-5373 (TDD).
Extension Service programs are open to all people without regard to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. The use of trade names in this article is solely for the purpose of providing specific information. It is not a guarantee, warranty, or endorsement of the product name(s) and does not signify that they are approved to the exclusion of others.