The present invention provides a method for controlling weed in wet rice cultivation which comprises: a step wherein an aqueous diluted solution that contains a herbicidal compound such as 1 (2 chloro 6 propylimidazo[1 2 b]pyridazin 3 ylsulfonyl) 3 (4 6 dimethoxypyrimidin 2 yl)urea is sprayed over a rice field and a step wherein the rice filed is flooded within a week after the treatment with use of the herbicidal compound.
