Having fire ant mounds throughout a lawn can limit your customers’ ability to use it while also posing a risk for people on the site. Red imported fire ants are a non-native, mound-building ant species that have become established in many states, particularly in the Southeast, says Heather Patterson, technical service manager for Quali-Pro.
Fire ants are 1/8 to 1/4 inches long with a reddish-brown color. Ants will aggressively defend mounds by running out and stinging intruders, says Todd Lowe, technical service manager for the Bayer Green Solutions team.
Experts say there are different ways to manage this pest, from granular insecticides and baits to liquid concentrates. Professionals should incorporate the following tips to get the best results. As always, read and follow control product label instructions.
DO
Act. “If you have active fire ant mounds, you’ll want to treat them when you discover them,” says Jen Browning, pest control adviser (PCA) and technical service representative for BASF. “Their mounds are a hazard in the landscape for people, animals and equipment.”
Use fresh bait. If you’re using bait, make sure it’s not past its prime. “Baits contain a food source that is taken back to the colony, and it may expire and become less appetizing,” Lowe says.
Prepare for population booms in summer after a rain. “If you can intercept the mated females before they start new colonies, that can reduce your colony pressure down the road,” Browning says.
Get a head start. “Bait applications in the fall are effective for targeting these fire ant colonies when they are in decline, helping to reduce the population and mounds that will be observed the following spring,” Patterson says.
Treat based on the number of mounds. “In areas with few mounds, it may be best to treat the mounds individually, whereas it is best to broadcast apply products in areas with many mounds,” Lowe says.
Mix it up. “Use multiple products and approaches if you have perennial pressure from fire ants — especially on lawns where people and animals play,” Browning says.
Consider site traffic. “Baits can be used in areas with low- to moderate-traffic, whereas it is best to apply products directly to mounds as a soil drench or powder/granules in areas with high traffic,” Lowe says.
Expand your reach. “Have a second line of attack with a spray insecticide in the synthetic pyrethroid (IRAC group 3A) or neonicotinoid (IRAC group 4A) chemistry class as a line of defense for ant trails, foragers and mating-flight aggregations,” Browning says. “Products that contain combinations of these groups are also available and will do double duty to control other turfgrass insect pests.”
DON’T
Pour bait into a mound. “Baits are carefully formulated to be attractive to their target species, and they leverage the natural behavior of ants to seek out food and bring it back to the colony,” Browning says. “The sudden intrusion of bait right into the mound can trigger them to swarm and reject the bait instead. Read the label for the product you select and apply it exactly as directed for best results.”
Confuse fire ants with other ant species. “Observing if the mound has a central entrance hole or not will help you determine which type of ant it may belong to,” Patterson says. “Fire ant mounds lack that central entrance hole, whereas mounds from harvester, pyramid and leafcutter ants have it.”
Treat before rain. “Make sure it’s not going to rain in the next few days so the ants can collect and carry (bait) into a colony,” Browning says.
Improperly use a repellent. “If ants are up against a foundation wall or next to a structure, it’s not recommended to use a product with repellent chemistries that could potentially drive them into the structure,” Patterson says. “Products like baits or liquid concentrates with non-repellent chemistries should be considered for controlling such colonies.”
