Effect of dose and mode of metribuzin application on Phalaris minor and yield of wheat (Triticum aestivum).

A study was conducted during winter (Rabi) season of 1998-2000 to find out optimum dose and mode of metribuzin application on its effect on Phalaris minor (Retz) and yield of wheat (Triticum aestivum L. emend. Fiori and Paol). The results showed that there was severe competition between wheat and little canary grass (Phalaris minor). Competition by yellow sweet clover (Melilotus indica), swincress (Coronopus didymus) and wood sorrel (Rumex sp.) which also invaded the field was insignificant. The average reduction in grain yield due to P. minor competition was 36%. Weed control treatments lowered weed population and weed biomass accumulation and boosted up crop yield. Application of metribuzin as post-emergence resulted in better control of weeds than its pre-emergence application. At 200 g/ha, it killed all the plants of swincress, yellow sweet clover and wood sorrel (Rumex sp.) and gave excellent control of Phalaris minor (94%). At 150 g/ha, its effect on e. didymus and Rumex sp. was almost similar to that of 200 g/ha,but slightly lower on P. minor (86%) and poor on M. indica. Pendimethalin gave moderate control ofP. minor and good control of M. indica, e. didymus and Rumex sp. The highest yield was recorded in hand weeding which was significantly superior to all other treatments. Metribuzin as post-emergence at 100 and 150 g/ha caused significantly higher increase compared to its application at 200 g/ha pr7 and post emergence and 150 g/ha pre emergence. It caused marked increase in productive tillers and yield attributes. 'The increase in yield attributes in pendimethalin was similar to that ofmetribuzin 100 g/ha pre-emergence.