SEQUENTIAL APPLICATION OF PRE- AND POST- EMERGENCE HERBICIDES FOR CONTROLLING WEEDS IN OLITORIOUS JUTE

Abstract

An experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh during April to September, 2014 to find out the weed control efficacy of different pre-emergence and post-emergence herbicides in tossa jute (Corchorus olitorious). Two pre-emergence herbicides viz. pendimethalin and pretilachlor; and three post-emergence herbicides viz. metamifop, quizalopfop-p-ethyl and fenoxapro-p-ethyl; were used in the experiment. Ten weed control treatments viz. no weeding control (T₁), weed free control (T₂), pendimethalin fb one hand weeding (T₃), pretilachlor fb one hand weeding  (T₄), pendimethalin fb metamifop (T₅), pretilachlor fb metamifop (T₆), pendimethalin fb quizalopfop-p-ethyl (T₇), pretilachlor fb quizalopfop-p-ethyl (T₈), pendimethalin fb fenoxapro-p-ethyl (T₉) and pretilachlor fb fenoxapro-p-ethyl (T₁₀) were used in a randomized complete block design with three replications. Weed control treatments significantly affected weed density and dry weight and exerted significant effects on plant height, plant diameter, stick diameter, green weight plant⁻¹, green weight of bark plant⁻¹, green weight of stick of plant⁻¹, dry fibre weight plant⁻¹, dry stick weight plant⁻¹, fibre yield and stick yield. The result revealed that application of pretilachlor fb fenoxapro-p-ethyl produced the lowest weed density and dry matter and resulted in the highest fibre and stick yield. The present study concludes that the highest weed control in tossa jute could be possible by applying pretilachlor @ 1 L ha⁻¹ at 2 days after sowing (DAS) followed by fenoxapro-p-ethyl @ 0.75 L ha⁻¹ at 25 DAS.