EVALUATION OF PYRIFTALID + BENSULFURAN METHYL ON WEED SUPPRESSION AND YIELD OF TRANSPLANTED RICE IN BANGLADESH

Abstract

Weed affect rice production and grain, which not only contest with crop yield but also ruin quality. Pyriftalid + Bensulfuran methyl is a new early post-emergence herbicide in Bangladesh. Field trials were conducted at Bangladesh Rice Research Institute (BRRI), Gazipur during Boro season of 2016-17 and Aman season of 2017 to evaluate the efficacy of the weedicide on weed suppression and performance of transplanted rice. Pyriftalid + Bensulfuran methyl @ 165, 207 and 248 ml a.i. ha−1 were applied along with Pyrazosulfuran Ethyl WP @ 12.5 g a.i. ha−1, while weed free and unweeded control was used for the efficacy assessment. Visual inspection indicated that this herbicide possesses high selectivity and not toxic to rice plants. The results revealed that the major weed flora associated with the transplanted rice was mainly comprised of two grasses, two sedges and four broadleaves in Aman, 2017, while two grasses, two sedges and two broadleaves in Boro, 2016-17. The most dominant weeds were Cyperus difformis, Echinochloa crus-galli, Scirpus maritimus and Monochoria vaginalis in both the growing seasons. Application of Pyriftalid + Bensulfuran methyl @ 207 ml a.i. ha−1 was most effective to suppress weed density and dry masses in both the seasons resulting increased grain yield more than 30% as compared to unweeded control. Therefore, Pyriftalid + Bensulfuran methyl @ 207 ml a.i. ha−1 should apply at one to two-leaf stage of weed may be recommended for effectively control weeds in transplanted rice.