WSU Extension


Lawn and Turf
2,4-D damage 
Anthracnose/Basal crown rot 
Brown blight 
Brown patch 
Curvularia blight (Fading out) 
Dog injury 
Dollar spot 
Fairy ring and mushrooms 
Leaf spot 
Microdochium patch (Pink snow mold) 
Necrotic ringspot 
Powdery mildew 
Pythium crown and root rot 
Red thread 
Septoria leaf spot (Tip blight) 
Slime molds 
Take-all patch 
Typhula blight (Gray snow mold) 
Yellow patch 
Chinch bugs 
European Chafer 
European crane fly 
Japanese beetle 
Japanese beetle 
Sod webworm 

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Caption: Thatching ant mound
Photo by: A.L. Antonelli
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