CONTROLE QUÍMICO DE PLANTAS VOLUNTÁRIAS DE SOJA ROUNDUP READY® EM DIFERENTES ESTÁDIOS DE DESENVOLVIMENTO

Abstract

This paper aimed to evaluate the effectiveness of herbicides [MSMA+diuron], [paraquat+diuron], metsulfuron-methyl and 2,4-D in control of volunteer plants of Roundup Ready® soybean, cultivar BRS Valiosa RR® when applied at various stages of development. The experiment was set up in Rio Verde city, in agricultural year 2007/08, using the randomized complete block experimental design in factorial scheme 5 x 3 (herbicide x application times) with four replications. The herbicide treatments were: metsulfuron- methyl (3,0 g ha-1), 2,4-D (1340 g ha-1), [MSMA+diuron] (1.800+700 g ha-1, respectively), [paraquat+diuron] (600+300 g ha-1, respectively) and control without spraying of herbicide; the second factor was the spraying of herbicides on phenological stages (V2, V6 and R2) of soybean plants. It was evaluated the percentage of controlling of volunteer soybean at 7, 14, 28 and 42 days after application (DAA) of herbicides, beyond the plant height and dry matter accumulation in shoots at 42 DAA. It was found that the herbicide treatments [MSMA+diuron] and 2,4-D provided greater control of volunteer plants of RR® soybean at stage V2 and the 2,4-D with spraying at V6. The treatment [paraquat+diuron] was more efficient in controlling at all phenologic stages. The metsufuron-methyl showed greater effectiveness of controlling when the spraying was done at stage R2.