Clear Choice® (Petro-Canada, Calgary, Canada) is an environmentally-friendly herbicide for broad-leaf weed control in turfgrasses. However, our laboratory and field data show that the herbicide also will help control tropical sod webworm, Herpetogramma phaeopteralis Guenee, populations in St. Augustinegrass. We believe this is the first report of an herbicide helping to control a pest insect in any turfgrass. Mortality is primarily caused in small and medium-sized larvae by a feeding response (starvation or toxicity via ingestion) rather than direct contact or volatilization. Future research will be needed to determine the specific chemical(s) responsible for the larval mortality and if the herbicide may also help control other insect pests of turfgrasses.