Comparative Efficacy of Pyrazosulfuron Ethyl and Bentazon with Acetamides for Weed Control in Transplanted BoroRice (Oryza sativa L.) in the Lower Gangetic Plain Zone of West Bengal, India

The efficacy of sulfonyl urea herbicide like pyrazosulfuron ethyl, benzothiadiazinone like bentazon alone and its combination with MCPA, clefoxydim and quinclorac were studied in comparison to traditional acetamides like butachlor and pretilachlor under field condition in transplanted boro rice. The dominating weed species in the experimental site were grasses like Echinochloa crusgalli, Paspalum distichum, sedges like Cyperus iria, Fimbristylis miliacea and broad leaved weeds like Ammania baccifera and Ludwigia parviflora. The herbicidal treatments were significantly superior to weedy check. There was 32.97% reduction in the grain yield of rice due to competition with weeds in the weedy plots. The pyrazosulfuron ethyl @ 30 g a.i. ha⁻¹ applied as pre-emergence, with an weed control efficiency of 71.78%, was found to be the most effective in controlling predominant weeds, in comparison to acetamide and benzothiadiazinone herbicides. In terms of profitability, application of pyrazosulfuron ethyl @ 20 g a.i. ha⁻¹ gave the highest gross and net return than other weed control treatments.