Coliseum Herbicide (active constituent rimsulfuron) is registered for the control of Wintergrass (Poa annua) & Ryegrass (Lolium spp) in Couch & Hybrid Couch.
Coliseum Herbicide allows turf managers to control the various genotypes of Wintergrass & Ryegrass that other herbicides have struggled to manage, and has shown to be user friendly compared to other herbicides in the sulfonylurea family.