The castor been (Ricinus communis L.) is a rustic plant, heliophile, resistant to drought, belonging to the family of Euforbiace. It is characterized by being sensitive to several herbicides and the competition imposed by harmful plants. This work had as objective to study the influence of different doses of the herbicide trifloxysulfuron-sodium in different states of development of the castor been, cultivar BRS Nordestina. The experiment was conducted during 2006, in a greenhouse of EMBRAPA - Cotton at Campina Grande, PB. The experimental design was totally randomized, with a factorial 4 x 4 + 1 design, consisting of four doses 5.0; 7.5; 10.0 and 12 g ha-1 of trifloxysulfuron sodium and four stages of the development of the plant (leaves cotyledon, two true leaves, two expanded leaves and four leaves) and an absolute control. In total 7 treatments were tested with four repetitions. The variables measured were growth reduction and dry matter of the castor been of the to cultivar BRS Nordestina. It was verified, for the variable growth reduction, reflected by the height and size of the plants, that there was a significant effect for doses and stages of the development and the interaction among them, and the youngest plants were more sensitive to the product. The herbicide that acts in the leaves and root, was phytotoxic to the castor been, cultivar BRS Nordestina, even in the lowest tested dose.
Euforbiace; growth reduction; dry matter; Ricinus communis L
