WSU Extension


Lawn and Turf : Ants
(revision date: 3/10/2017)

Ants are primarily a nuisance pest in lawns. Occasionally, they may kill the grass, causing an aesthetic problem. Various species may occur in lawns, including harvester ants which can have a severe sting.
Management Options

Non-Chemical Management
  • Repeated flooding of infested areas can drive ants out of their nests and force them to relocate. Flooding must be done every few days until the ants move.
  • Tolerate ants when possible, as they can be beneficial insects.
Select non-chemical management options as your first choice!

Chemical Management

Effective ant control normally requires destruction of the queen. In most cases, this necessitates one or more applications of a liquid or granular insecticide. In situations where only a few colonies are present, apply insecticides directly to colony openings and the areas immediately surrounding the mounds.

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.
  • Monterey Garden Insect Spray [Organic]
    Active ingredient: spinosad (spinosyn A+D)  |  EPA reg no: 62719-314-54705
  • This list may not include all products registered for this use.
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Caption: Thatching ant mound
Photo by: A.L. Antonelli