This study had the purpose of evaluating the efficiency and selectivity of the herbicide clethodim, in two formulations (120 and 240 g/l) for weed control in onion crop. The experiment was realized at the University of Ponta Grossa, in Brazil, in 1998. The experimental design was of randomized blocks with four replicates. The following treatments were evaluated: clethodim (120 g/L + mineral oil) using doses of 72, 84 and 96 g i.a./ha; clethodim (240 g/L) with 84 g i.a./ha added with 1.0 L/ha of mineral oil; weed free and weedy. The onion cultivar used was Baia Periforme and the following weeds were prevailing: Brachiaria plantaginea (capim-papuã), Digitaria horizontalis (capim-milhã) and Eleusine indica (capim-pé-de-galinha). Evaluations were performed at 7, 14, 28 and 42 days after treatments applications when it was observed that clethodim (120 g/L) at the doses 84 and 96 g i.a./ha and clethodim (240 g/L) were similar and showed efficient control to Brachiaria plantaginea, Digitaria horizontalis and Eleusine indica; these treatments caused a slight reduction of plants height at 7 days after application but later on it was no more observed. The production from these treatments was similar among them; however they were superior when compared to control without weeding.
Allium cepa L.; weeds; chemical control
