Landscape Management, February 2019

SUN DWELLER Fire ants prefer open sunny areas on lawns but can also be found elsewhere in the turf TIPSHEET Background Fire ants are easily identified by the mounds they build The above ground portion of the mound is usually conical and can be a few inches tall and several inches across to as much as a few feet across They can be found anywhere on a lawn or landscape The insects tend to move down further into the ground when its dry Mounding will occur after rain events because the ants try to raise their brood above the saturated soil to get away from the moisture A fire ant colony established in June could contain 15000 insects one year later A mature colony of three years may contain 100000 to 500000 workers and several hundred winged forms You can determine if fire ants are active by putting out a piece of greasy food and checking it 30 minutes later Fire ants prefer open sunny areas found on lawns though you can find fire ant mounds in any area of a lawn The size of the mound depends on the lawns soil characteristics and how frequently the mound is disturbed Control tips There are several different species of fire ants the red imported fire ant and southern fire ants chief among them but the species of ant doesnt make any difference in control method If youre walking lawns and laying down fertilizer always be cognizant of fresh fire ant mounds Spraying insecticide on foraging ants will not control a colony and spraying a nest may cause the colony to disperse which could make control even more difficult Treat the mounds either with liquids granular products watered in over the top of the mound or bait control Digging up mounds typically results in the movement of nests or dispersal of the fire ant mound A granular or liquid broadcast program provides good residual and potentially preventive control for fire ants In the case of a new queen flying in from a neighboring yard the broadcast treatment should be able to stop the queen fire ant from starting a fresh colony Fire ant baits will take longer than broadcast treatments which can knock mounds down within 15 minutes or less and provide residual treatment in the yard for 30 to 90 days For lawns with a wide infestation broadcast treatments are ideal and a technician can spray larger mounds with additional applications of insecticide For direct mound treatments technicians should treat the area 1 to 2 feet outside the mound Whatever theyre using to treat the mound technicians should be sure to use enough force to break the apex of the mound to get the material down into the mound itself to kill the insects Unless the apex of the mound is broken fire ants will simply move the mound away to avoid the insecticide BY ABBY HART LM SENIOR EDITOR HIGH AND DRY Fire ants typically build mounds after rain events to escape saturated soil Fire ant control PHOTOS DAVID SHETLAR FMC BAYER Turf Ornamental SOURCES Brian Mount insecticide technical service manager FMC Bayer Green Solutions Team FEBRUARY 2019 LANDSCAPEMANAGEMENT NET 33 FIRE ANTS M O Fire ants can be easily identified by the conical above ground mound that they build