Surfatante siliconado e glyphosate no controle de Brachiaria decumbens

Abstract

-The research goal was to evaluate the effects of silicone surfactant and simulated rainfall in glyphosate efficiency in controlling Brachiaria decumbens. The experiments were carried out at (a unit of the University of São Paulo) Escola Superior de Agricultura Luiz de Queiroz (ESALQ -Luiz de Queiroz College of Agriculture) in greenhouse conditions, in a randomized block design with four replications. In one experiment, a simulated rainfall of 10 mm was carried out, 30 minutes after treatments application, and in the other there was no simulation. The treatments were arranged in a 5x3 factorial arrangement, with the first factor corresponding to the doses of glyphosate (0, 135, 270, 540 and 1080 g ha -1 a.e.), and the second one to the doses of silicone surfactant (0, 50 and 100 mL ha -1 ). The applications were performed at 30 days after sowing. In the presence of a simulated rainfall, the percentage of control was increased and chlorophyll content was reduced in the dose of 135 g ha -1 a.e. of glyphosate, together with 100 mL ha -1 of silicone surfactant. Increase in lipid peroxidation was also observed with the addition of 100 mL ha -1 . In the experiment without a simulated rain, at seven days after treatments application, a higher percentage of control was observed at doses of 540 and 1080 g ha -1 a.e. with 100 mL ha -1 of silicone surfactant. Therefore, the use of silicone surfactant at a dose of 100 mL ha -1 increases the efficiency of glyphosate in the control of Brachiaria decumbens in the absence of simulated rain and rain conditions held for half an hour after application.