Resistance to isoproturon in Phalaris minor Retz. in Punjab.

摘要

Investigations were conducted during 1993-94 and 1994-95 to study the occurrence of resistance in Phalaris minor to isoproturon and to find effective alternative herbicides to control the resistant biotypes. Seeds of different Phalaris biotypes werecollected from farmers' fields where poor or no control of this weed was noticed over the previous three to four years with post-emergence application of isoproturon. Most of the biotypes were not controlled by isoproturon even at double the recommendeddose (1.88 kg ha-1). All the biotypes were controlled by the post-emergence application of tralkoxydim at 0.35 kg ha-1 and diclofop-methyl 0.90 kg ha-1, applied at the 2- to 3-leaf stage of Phalaris. These studies clearly show that Phalaris populationshave developed resistance to isoproturon. All (resistant and susceptible) biotypes, when grown in association with wheat, suffered severe competition, reflected in greatly reduced shoot biomass as compared to Phalaris monocultures.