Efficacy of different herbicides against complex weed flora in direct-seeded basmati rice (Oryza sativa)

Abstract

A field experiment was carried out during the rainy (kharif) season of 2013 at the Chaudhary Charan Singh Haryana Agricultural University, Regional Research Station, Karnal, India, to evaluate the different combinations of herbicides as alone and tank-mix to control the dynamic and complex weed flora in direct-seeded basmati rice (Oryza sativa L.). Bispyribac-Na was the most effective against grassy weed Echinochloa crus-galli, and pyrazosulfuron, azimsulfuron and ethoxysulfuron against broad-leaf weeds and sedges. Tank-mix application of fenoxaprop showed antagonistic effect on efficacy of bispyribac against weeds. Among the herbicidal treatments, application of pendimethalin 1,000 g/ha (PRE) followed by(fb) tank-mix combination of bispyribac-sodium 25 g/ha with pyrazosulfuron 25 g/ha or azimsulfuron 20 g/ha or ethoxysulfuron 18.037.5 g/ha (weed-control efficiency at 60 DAS: 93.395.6%) were found to be the best combinations for control of complex weed flora in direct-seeded rice, with significant improvement in effective tillers (71.373/m row length), grain yield (4,0134,103 kg/ha), net returns ( 108,856113,485/ha) and benefit: cost ratio (2.452.53) as compared to weedy check (35.0/m row length, 1,552 kg/ha, 1,590/ha and 1.02 respectively).