Effect of Several Herbicides on Blyxa aubertii L. and Chara braunii Gmelin in Paddy Field

This study was conducted to understand controlling effects on the Blyxa aubertii L. and Chara braunii Gmelin by soil-applied herbicides at different application times. The number of leaves of B. aubertii at 7, 10, and 15 days after harrowing (DAH) was 1.2, 4, and 8.8, respectively. B. aubertii could be controlled by other herbicides having different modes of action from sulfonylurea herbicides, such as benzobicyclon, oxadiazon, benzobicyclon+pretilachlor, and fentrazamide when they were applied at 0 DAH, carfentrazon, pryrazolate+butachlor, and bensulfuron+fentrazamide when they were applied at 7 DAH, pyrazosulfuron+fentrazamide, benfuresate+bifenox, pyrazosulfuron+pyrazolate+simetryn, thiobencarb+simetryn, and pyrazosulfuron+mefenacet when they were applied at 13 DAH. However, the B. aubertii was controlled only 31-84% by the recommended rate and 2 times of recommended rate of azimsulfuron and controlled 35-70% by sulfonylurea herbicide-based mixtures, azimsulfuron+thiobencarb, pyrazosulfuron+indanofan, pyrazosulfuron+molinate, pyrazosulfuron+pyriminobac, and cinosulfuron+pyriftalid when they were applied at 7 and 13 DAH. On the other hand, Chara braunii could be controlled over 92% by oxadiazon and butachlor when they were applied at 0 DAH, butachlor when it was applied at 7 DAH, and pyrazosulfuron+fentrazamide, benfuresate+bifenox, thiobencarb+simetryn, and pyrazosulfuron+mefenacet when they were applied at 13 DAH. However, similar to the B. aubertii, the Chara braunii was controlled only 18-35% by the recommended rate and 2 times of recommended rate of azimsulfuron and controlled 12-54% by sulfonylurea herbicide-based mixtures, bensulfuron+butachlor, bensulfuron+thiobencarb, azimsulfuron+thiobencarb, pyrazosulfuron+molinate, bensulfuron+benfuresate, pyrazosulfuron+carfentrazon+pyriminobac, pyrazosulfuron+pyriminobac and cinosulfuron+pyriftalid when they were applied at 7 and 13 DAH. Thus, results from these experiments indicate that the B. aubertii and Chara braunii from the paddy fields in Chonnam province may be resistnat to sulfonylures herbicides.