Comparison of Spring and Summer Herbicide Applications for Nutsedge Control in Turfgrass

Abstract

Sulfosulfuron, imazaquin, and halosulfuron applied beginning in May exhibited a high degree of nutsedge control from August to the end of September. Late spring initiated applications of imazaquin, sulfosulfuron, and trifloxysulfuron gave consistent nutsedge control that was better than 85% for most of the rating dates through the summer. Halosulfuron and flazasulfuron tended to decline in nutsedge control efficacy about one month after applications. The summer timing series of three monthly applications that began in July showed that sulfosulfuron and trifloxysulfuron provided an average of better than 90% nutsedge control throughout the summer. Applications of all herbicides in May caused ryegrass injury. Halosulfuron applications initiated in May were marginally safer on overseeded ryegrass while providing a moderate degree of nutsedge control. Bermudagrass was very slow to recover and to achieve full cover in sulfosulfuron and imazaquin treated plots.