Selectivity of post-emergence herbicides to crambe

Abstract

Crambe is a dedicated oilseed crop suitable for production of industrial feedstocks. Due to the lack of information of post-emergent herbicides, the aim of this study was to evaluate the selectivity of post-emergence herbicides to crambe. The experiment was conducted in Maracaju, MS, Brazil, in 2013. Clethodim (120 g ha^-1 a.i.), haloxyfop-p-methyl (63.35 g ha^-1 a.i.), fomesafen + fluazifop-p-butil (125 + 125 g ha^-1 a.i.), fomesafen + fluazifop-p-butil (187.5 + 187.5 g ha^-1 a.i.), nicosulfuron (45 g ha^-1 a.i.) herbicides without and with mineral oil, and a control without herbicide application were assessed. Evaluations were performed 7, 14, 21 and 28 days after herbicide application based on the percentage of crambe plants with visual phytotoxicity, on the percentage of dead plants caused by herbicides, and the grain yield. In general, mineral oil increased the phytotoxic effects of herbicides on crambe plants when sprayed post-emergence. The mineral oil addition to haloxyfop-p-methyl increased the phytotoxicity to crambe plants. The herbicide fomesafen + fluazifop-p-butil and nicosulfuron were harmful to crambe plants with or without mineral oil, and clethodim (with and without mineral oil) and haloxyfop-p-methyl (without mineral oil) were harmless to crambe plants and can be used on post-emergence.