PURPOSE: To obtain a herbicide, especially a selective controller for weeds in a paddy field, comprising 5-chloro-1,2,3,-thiadiazole-4-carboxamide or 5- chloro-1,3,4-thiadiazole-2-carboxamide as an active ingredient.
CONSTITUTION: This herbicide comprises 5-chloro-1,2,3-thiadiazole-4-carboxamide of formula I or 5-chloro-1,3,4-thiadiazole-2-carboxamide of formula II as an active ingredient, shows excellent activity against various weeds emerging in a paddy field and extremely low phytotoxicity to crops. The herbicide is useful for controlling weeds in a paddy field. The amount of the application of the herbicide is usually 0.1-100g, preferably 1-30g per 1 are. The herbicide has wide herbicidal activity, can wither a great number of important weeds such as barnyard grass, monochoria, bulrush, umbrella plant, broadleaf weeds, etc., at a low treating concentration but does not provide rice plant with drug toxicity.
ONO SATORU
ASADA TORU
