Performance of early post-emergence herbicide in irrigated groundnut (Arachis hypogea L.) in red sandy loam soils of Tamil Nadu.
A field investigation was carried out at Agricultural Research Station, Tamil Nadu Agricultural University, Bhavanisagar during kharif 2009 and 2010 to evaluate the early post emergence application of new formulation of imazethapyr (10% SL) on weed control in groundnut. Based on two years of field experimentation, it was found that early post emergence application of imazethapyr (10% SL) at 200 g ha-1 gave significantly lower total weed density, weed dry weight and higher weed control efficiency at all the stages. However, imazethapyr at 200 g ha-1 and 150 g ha-1 had slight phytotoxicity on groundnut upto 15 DAS. Application of new formulation of imazethapyr (10% SL) at 100 g ha-1 as early post emergence herbicide kept the weed density and dry weight below the economic threshold level and increased the pod yield (1602 and 1900 kg ha-1). This treatment was found to be on par with the application of 150 g ha-1 (1580 and 1854 kg ha-1) in groundnut.