Fire Ants in Tampa Lawns: Mounds and Control
Red imported fire ants build loose dome shaped mounds with no visible opening, and they swarm out and sting within seconds when the mound is disturbed. The sting leaves a white pustule after a day. Mounds appear fastest on new sod and disturbed ground after summer rain. Broadcast bait across the whole lawn works better than treating mounds one by one.
How to identify it
The mound is the easiest identifier. Fire ant mounds are loose, fluffy domes of worked soil, a few inches to over a foot across, with no single opening on top. They show up in the open sunny parts of a lawn, along driveway edges, next to sidewalks, around irrigation boxes and against fence posts, usually a day or two after heavy rain.
The ants themselves are reddish brown, and a colony contains several sizes from about an eighth to a quarter inch. The behavior settles it: disturb a mound and hundreds pour out within seconds and run up anything touching it, then sting more or less together. The sting burns immediately and leaves a small white pustule within a day.
Where they show up and why
Disturbed, sunny ground. That is why the worst yards in Hillsborough County are the newest ones: the subdivisions off Boyette Road, through Riverview and Brandon, and the current phases in New Tampa, where sod went down on cleared land in the last year or two.
Clearing land removes the native ant species that would normally compete with them, and fresh sod on loose soil is easy digging. Newly mated queens fly after summer rains and land wherever they can, which is why a clean lawn can show dozens of mounds within two weeks.
What works, and what does not
Broadcast bait over the entire lawn is the treatment that actually changes the yard. Foragers carry the granules back and feed them to the colony including the queen, which reaches nests that have not surfaced yet. It works slowly, over weeks, and goes down on a dry lawn according to the product label.
Individual mound treatment is for the mound by the play set or the front walk that you need handled today. Used on its own across a whole yard it is endless work, because you are treating the visible fraction.
Walk the lawn after heavy summer rain and report the mounds near a door, a play area or a pet run first.
Common questions
Why do new mounds appear right after I treat?
Two reasons. Treating a mound removes that colony and leaves open ground for a new queen to claim, and most colonies on a lawn have no visible mound yet. Mating flights follow summer rain, so fresh colonies land continuously through the wet season. A seasonal broadcast bait reaches them before they surface.
Do home remedies work on a mound?
Boiling water kills part of a colony and also kills the grass and any plant roots it reaches. Gasoline is dangerous and illegal to use this way. Shovelling a mound into another mound is an old story that does nothing useful. The queen sits deep and survives anything that treats only the top of the mound.
What should I do about a sting?
Wash the area, use a cold compress, and leave the pustule that forms alone so it does not become infected. Most stings are painful and then uneventful. Anyone with difficulty breathing, swelling away from the sting site, dizziness or a history of severe reactions to stings needs emergency medical help straight away.