Influence of season and surfactant on efficacy of glyphosate shown by ED50, ED75 and ED93 values in Cyperus rotundus management.

摘要

A pot study was conducted to investigate the effects of application season (E1-E9) and addition of surfactant (Triton X 100 at 0.01%) on the efficacy of glyphosate (at 0, 20, 40, 80, 160, 320, 640, 1200 and 2400 g a.i./ha) in C. rotundus management. The ED50, ED75 and ED93 values were determined. Low ED50 values were observed during the E6 season (July-September). Surfactant application with glyphosate reduced the ED50 value by 3.67-3.46 times during July-September and November-January growing seasons, suggesting that surfactant reduced the required concentration of glyphosate without losing efficacy.