Optimizing the surfactant dose for sulfosulfuron and ready mix combination of sulfosulfuron and carfentrazone against weeds in wheat

Field and pot studies were conducted to determine the efficacy of sulfosulfuron and ready mixture, sulfosulfuron + carfentrazone- 45 (25+20) WDG at different surfactant doses against complex weed flora of wheat. The weed control, particularly the grass was significantly poor, when sulfosulfuron or its ready mix combination with carfentrazone was applied without surfactant compared with surfactant. The grass (Avena ludoviciana, Echinochoa crusgalli, Phalaris minor and Polypogon monspeliensis) weed control with sulfosulfuron or ready mixture (RM) of sulfosulfuron + carfentrazone- 45 WDG was similar at surfactant doses of 625, 750 and 1250 ml/ha indicating the possibility of reducing the surfactant doses by 40–50% from the present recommendation of 1250 ml/ha in India. The optimum dose of RM, sulfosulfuron + carfentrazone was 45 (25+20) g/ha with 625–750 ml/ha surfactant. This combination was superior over sulfosulfuron, due to the control of Rumex dentatus, thereby increased the wheat yield by 7.6% on an overall mean basis. The RM, sulfosulfuron + carfentrazone with surfactant was similar to ready mixtures, Total (sulfosulfuron 75 + metsulfuron 5)-80 WDG at 32 (30+2) g/ha and Atlantis (mesosulfuron + iodosulfuron) at 14.4 (12+ 2.4) g/ha in controlling weeds and producing wheat yield. The carry over effect of sulfosulfuron involving treatments (sulfosulfuron, sulfosulfuron + metsulfuron, sulfosulfuron + carfentrazone) was observed on succeeding maize (Zea mays L.) crop. At 2X dose of sulfosulfuron + carfentrazone (50+40 g/ha), the reduction in maize biomass was 62.6–73.0% in comparison to weed free check.