Pendimethalin, Resistance, Phalaris minor, Sulfosulfuron, Sulfosulfuron + metsulfurn, mesosulfuron + iodosulfuron

In this study, response of 20 Phalaris minor Retz. (little seed canary grass) populations against sulfosulfuron and its ready–mix formulation sulfosulfuron + metsulfuron and mesosulfuron + iodosulfuron was studied. Out of 20 populations, 12  showed high resistance, 8 showed  medium resitance and none were susceptible to sulfosulfuron (25 g/ha). GR50 value was in the range of 30-110 g/ha in P. minor populations  tested. In wheat, it was more than 200 g/ha. Eleven populations showed resistance to ready mix formulation of sulfosulfuron + metsulfuron, 8 populations  were medium R/medium S and one population was susceptible. Similarly, 11 showed resistance to ready mix formulation of mesosulfuron +  iodosulfuron, 7 populations  were medium R/medium S and one biotype was susceptible. GR50 values tested were in the range of 30-110 g/ha in contrast to 5 g/ha at the time of recommendation.