Field experiments conducted at the Research Farm of Department of Agronomy, Himachal Pradesh Krishi Vishvavidyalaya,.Palampur during rabi seasons of 1990–91 to 1992–93 revealed that post-emergence application (35 DAS) of isoproturon at different rates (1.0, 1.25 and 1.50 kg/ha) was found effective in reducing weed density and biomass significantly as compared to pre-emergence application at above said rates. Post-emergence application of isoproturon at 1.0 and 1.25 kg/ha remaining at par produced significantly higher plant height, grain, stalk and fibre yield of flax as compared to pre-emergence application at different rates. However, post-emergence application of isoproturon at 1.50 kg/ha combination of isoproturon+2, 4-D (1.0+ 1.0 kg/ha) were found to have phytotoxic effect on flax plants.
