Herbicidal activity and characteristics of pyraflufen-ethyl for controlling broad-leaved weeds in cereals

Pyraflufen-ethyl [ ET-751, ethyl 2-chloro-5-(4-chloro-5-difluoromethoxy-1-methylpyrazol-3-yl)-4-fluorophenoxyacetate] is a potent Protox inhibiting herbicide which is also designated as a peroxidizing or photobleaching herbicide. In this paper, we demonstrated the herbicidal activity and characteristics of pyraflufen-ethyl as a cereal herbicide. Pyraflufen-ethyl showed excellent selectivity between cereal crops (wheat and barley) and a.broad range of important broad-leaved weeds in post-emergence application. Its herbicidal activity was significantly higher than that of the existing cereal herbicides such as bifenox, ioxynil and mecoprop-p and comparable or even superior to carfentrazon-ethyl and metsulfuron-methyl, which are known as low use-rate herbicides. Pyraflufen-ethyl was also characterized by the fast herbicidal action and excellent activity against Galium aparine, one of the most troublesome broad-leaved weeds infested in winter cereal fields in West Europe. Field trials conducted in U.K. and France in 1990/1991 proved that pyraflufen-ethyl possessed high potentiality as a post-emergence cereal herbicide for controlling broad-leaved weeds selectively at rates of 6-12 g a.i./ha.