Fire ants are the most common insect pest of home lawns. Fire ant control is a never-ending battle in the South, but there are steps you can take to keep your lawn and landscape relatively free of these troublesome pests.
The easiest, cheapest, most effective thing you can do to control fire ants is to use baits. Learn to use baits properly and preventively, and you will reduce the number of mounds in your yard by 80 to 90 percent. If you want even better control, you can supplement your baiting program with some additional tricks, like spot-treating mounds that survive the bait treatments. According to Dr. Dan Suiter, a UGA Cooperative Extension entomologist with the College of Agricultural and Environmental Sciences, attacking fire ant colonies now will help next spring when they start to swarm again. Dr. Suiter says fire ants are easier to kill now 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,” Suiter said. “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. Actively foraging ants will pick up bait and carry it into the nest within the first hour or two. If the ants are inactive, the bait may not appeal to the ants by the time they find it.
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. “Quite often, you don’t even know they’re there,” he said. “But if you don’t treat them, they’ll become the big mounds you see next year.
Fourth, and the one thing that makes fall the single best time to treat fire ants, Suiter said, is that it’s followed by winter. Extreme cold is tough on fire ants. This makes baits even more effective in the fall. Baits also take a long time to work. They weaken colonies and make them less able to respond to the challenges of winter weather. Young colonies are especially vulnerable because they don’t have many workers. So, they can’t respond very quickly to the need to escape freezing temperatures.
So, how do you treat for fire ants if you don’t know where they are? The key to success with baits is applying them as broadcast treatments instead of treating only individual mounds. You will never win the battle against fire ants by only treating individual mounds. In addition to the big mounds you can easily see—or trip over—there are a lot of little colonies that are just getting started. If you eliminate only the big mounds, the small colonies will thrive because they have less competition, and they will quickly grow into large mounds. Broadcast bait treatments target all colonies in the yard, regardless of size. Broadcasting fire ant bait is the first step in the process. Use fresh bait and apply it using the label directions. Never apply bait using a spreader that’s been used to spread fertilizer. Fertilizer can contaminate the smell of the bait. Use only a new spreader, dedicated only to the use of spreading fire ant bait.
The insecticides used in fire ant baits have to be slow-acting to allow time for the insecticide to be spread throughout the colony. A fast-acting insecticide would kill the worker ant before she got back to the colony with the bait granule, defeating the objective. Depending on which bait you use, it can take 2 to 6 weeks to obtain maximum control. Baits work great, but you have to be patient!