There are many species of ants that occur in lawns and other turfgrass areas. Most ants do not require controls and are considered beneficial. The ants found in Iowa lawns are not biting or stinging pests. The fire ants of the southern U.S., well known for their aggressive behavior and painful stings, are not present in Iowa.
Ants in the lawn occasionally become a nuisance by constructing mounds or small hills in the lawn or by invading the home in search of food. These mounds may be unsightly, may cause lawn unevenness, and if large, may smoother out the surrounding grass.
To avoid some of the worst ant hill activity rake or "wash" (with a water stream from the garden hose) on a regular and frequent basis anthills that appear above the grass tops. The need for such maintenance will be greatest during periods of prolific ant nesting activity (such as during periods of wet spring weather). If necessary, you can spot treat anthills with an insecticide such as diazinon or Dursban. Rake the anthill flat and sprinkle granules onto the soil surface or drench the mound area with diluted solution. Read and carefully follow instructions on the insecticide label. If granules were used, rake the area lightly after application. Irrigate the mound area to move the insecticide ingredient into the soil and away from the surface where it may be exposed to people, pets or wildlife. Keep children and pets away from the treated area until the grass has dried.
Pest control operators or lawn care professionals can also treat ant mounds. Overall lawn treatments specifically for ant colonies are seldom necessary.
This article originally appeared in the May 14, 1999 issue, p. 58.