Turfgrass tolerance to tetflupyrolimet applications for preemergence grassy weed control

Abstract Tetflupyrolimet (Dodhylex™ Active, FMC Corporation) is a novel herbicide inhibiting de novo pyrimidine biosynthesis that controls grassy weeds preemergence in rice ( Oryza sativa L.) production. Field trials were conducted from 2021 to 2024 to evaluate turfgrass tolerance to tetflupyrolimet applications for annual bluegrass ( Poa annua L.) and smooth crabgrass [ Digitaria ischaemum (Schreb.) Schreb. ex Muhl.] control. Tolerance was evaluated on seven turfgrass species, including creeping bentgrass ( Agrostis stolonifera L.), Kentucky bluegrass ( Poa pratensis L.), tall fescue [ Schedonorus arundinaceus (Schreb.) Dumort.; syn.: Festuca arundinacea Schreb.], hybrid bermudagrass [ Cynodon dactylon (L.) Pers. × Cynodon transvaalensis Burtt-Davy], and manilagrass [ Zoysia matrella (L.) Merr.] at various mowing heights ranging from 3.8 to 12.5 mm. Separate experiments were conducted on each turfgrass species to evaluate tolerance in both fall and spring. Tetflupyrolimet was applied at rates of 0, 25, 50, 100, 200, 400, 800, 1600, 3200, or 6400 g ai ha −1 . No injury was observed on any warm-season turfgrass species in either season, whereas cool-season grass tolerance varied among species each season; however, cool-season turfgrass tolerance for all species was greater in spring than fall. While efficacy of tetflupyrolimet (400 g ha −1 ) for preemergence D. ischaemum control varied among years, mixtures of tetflupyrolimet (400 g ha −1 ), pyroxasulfone (128 g ai ha −1 ), and rimsulfuron (35 g ai ha −1 ) applied preemergence or early postemergence effectively controlled multiple-resistant P. annua in both seasons. Overall, these findings highlight that warm-season turfgrasses are highly tolerant of tetflupyrolimet applications for P. annua or D. ischaemum control.