Pot experiments were conducted at the Research Farm of Department of Agronomy, PAU, Ludhiana during 1998–99 and 1999–2000 to calculate the GR50 value of different herbicides against Phalaris minor. Experimental results revealed that in case of isoproturon, the dose increased 1.7 times than the recommended dose for 50% reduction in growth of P. minor. In case of alternate herbicides viz., clodinafop, fenoxaprop and sulfosulfuron though it provided good control of P. minor in both the years, but their GR50 value increased slightly in the 2nd year indicating that there may be chances of occurrence of cross resistance of P. minor against these herbicides in the near future and their order of occurrence may be fenoxaprop-p-ethyl>clodinafop>sulfosulfuron.
