Toxicity of the nicosulfuron herbicide on rice (Oryza sativa L.).
The toxic effects of the herbicide nicosulfuron to rice cv. Milagro Filipino Depurado were determined under greenhouse conditions. Nicosulfuron at 40 and 80 g/ha, the mixture of nicosulfuron + 2,4-D (40 + 480 g/ha) and a nonherbicide treatment were evaluated. Herbicide treatments were applied to plants 3, 10, 17 y 24 days after emergence (DAE). Toxicity was evaluated seven days after application (DAA) and plant height was measured at seven, 15 and 30 DAA; the plant’s dry matter was also quantified at 30 DAA. The highest toxicity was observed in plants treated at three and 10 DAE with nicosulfuron at 80 g/ha and the mixture of nicosulfuron + 2,4-D. The height of rice plants applied with any of the herbicide treatments was significantly lower than that of the non-treated plants at seven and 15 DAA. The nontreatedplants were still significantly taller than the treated plants at 30 DAA, except forthose treated at three DAE with 40 g nicosulfuron or with the mixture nicosulfuron + 2,4-D, at 10 DAE. Plants applied with 40 g nicosulfuron at 10 DAE or later had dry matter productions statistically similar to that of non-treated plants, while plants treated with 80 g nicosulfuron produced the lowest dry matter.