Estimation of GR50 Values of New Herbicides Used to Control Isoproturon Resistant Phalaris minorin Wheat

Pot experiments were conducted to find out GR50, values of isoproturon, clodinafop, sulrosulfuron and fenoxaprop-p-ethyl for controlling Phalaris minor. Clodinafop, sulfosulfuron and fenoxaprop-p-ethyl were recommended at 60, 25 and 100 g ha−1. On an average of two years, GR50 values for isoproturon, clodinafop, sulfosulfuron and fenoxapropp-ethyl were found to be 1210, 2.47. 2.08 and 7.58 g ha−1, respectively. Among the alternate herbicides, lowest GR50, value was observed in clodinafop which was followed by sulfosulfuron and fenoxaprop-p-ethyl and these values were many times lower than their recommended doses; however. GR50 values for isoproturon were found to be much higher than even its recommended dose.