Revista Brasileira De Herbicidas 2015; 14(3): 243-247

ISSUE Cover

Alternative control of ryegrass biotypes resistants to clethodim

DOI: 10.7824/rbh.v14i3.424

Ryegrass is an annual cycle weed, present in winter crops, orchards and vineyards of southern Brazil. The species is typically controlled by the herbicide clethodim. However, continued use of this product selected resistant biotypes. Thus, the objective of this research was to evaluate the response of ryegrass populations resistant to clethodim to the application of herbicides of different mechanisms of action, and propose chemical control alternatives. An experiment was carried out in the Brazilian city of Coqueirosdo Sul, in a randomized block design with three replications. The treatments assessed were: nicosulfuron (60 and 120 ga.i. ha-1), iodosulfuron-methyl (6 and 12 g a.i. ha-1), paraquat (400 and 800 g a.i. ha-1), ammonium-glufosinate (600 and 1200 g a.i. ha-1), clomazone (750 and 1500 g a.i. ha-1), tembotrione (100 and 200 g a.i. ha-1), clethodim (144 and 288 g a.i. ha-1), haloxyfop-methyl (60 and 120 g a.i. ha-1) and a control without the application of a herbicide. Herbicides tembotrione, nicosulfuron, iodosulfuron-methyl, clomazone, clethodim and haloxyfop-methyl were not efficient to control ryegrass. However, only herbicides paraquat and ammonium-glufosinate caused weed control and may be used to control populations of ryegrass resistant to herbicide clethodim.