Soapy-water Flush

Soapy-water flush is the most effective monitoring technique for mobile insects in thatch, leafy areas and the soil profile. Soap irritates the insect exoskeleton and external orifices, forcing them to move to the turfgrass surface.


Step 1. Fill a container with 1-2 gallons (3.8-7.6 liters) of water. Put 1-2 tablespoons (15-30 milliliters) of lemon-scented liquid dish detergent. When using the solution on bentgrass, dilute the rate further to minimize turfgrass stress.

Step 2. Mix by hand until soap suds appear.

Step 3. Slowly pour the soap mixture over approximately one square yard (1 square meter) of turfgrass. When placing a soap flush, be sure to place in healthy turfgrass around damaged areas. Insects are less likely to be recovered from heavily-damaged turfgrass.

Soapy-water Flush Sampling, Step 1
Soapy-water Flush Sampling, Step 2


Step 4. Watch closely for 5-10 minutes for insects to emerge.

Note. Repeat applications of the soap mixture in different areas might be necessary to gain a full understanding of the insect’s population density.

The following insects can be monitored with soapy-water flush:

  • Annual bluegrass weevil (adults)
  • Black turfgrass ataenius (adults
  • Bluegrass billbug (adults)
  • Chinch bugs (nymphs and adults)
  • Cutworms (larvae)
  • Fall armyworms (larvae)
  • Mole crickets (nymphs and adults)
  • Tropical/Sod webworms (larvae)