Abstract
The herbicidal performance of MT-147, (2R,3S,3aS,9bR)-2-ethyl-3-(2-fluorobenzyloxy)-6,7-methylenedioxy-3,3a,5,9b-tetrahydro-2H-furo[3,2-c][2]benzopyran, was examined as a graminicide for paddy rice. MT-147 completely controlled barnyardgrass from pre-emergence up to the 2.0-leaf stage at 300 g a.i./ha by submerged application; however, the efficacy decreased as the leaf stage proceeded further. The herbicidal activity of MT-147 was not influenced by water depth, but it was slightly affected by the seeding depth of barnyardgrass, the activity being lower when the seeding depth was deeper. MT-147 had no phytotoxicity to transplanted rice at 300 g a.i./ha but phytotoxicity was observed when rice seedlings were placed on the soil surface and the roots were exposed to water. Bromobutide remarkably increased the herbicidal activity of MT-147 against barnyardgrass. In this study, it was revealed that a novel 3,3a,5,9b-tetrahydro-2H-furo[3,2-c][2]benzopyran, MT-147, has excellent herbicidal activity against barnyardgrass, and its activity was enhanced by bromobutide.
