Factors influencing the herbicidal activity of cafenstrole (N, N-diethyl-3-mesitylsulfonyl-1H-1, 2, 4-triazole-1-carboxamide) against Echinochloa oryzicola Vasing in paddy fields were investigated in a greenhouse. The herbicidal activity of cafenstrole (1-3g a. i./a) against the plant was not affected by the temperature (Fig. 1), the soil type (Fig. 2), the flooding water depth in the range of 1-6cm (Fig. 3) or water leakage (Fig. 4). The activity of cafenstrole, however, decreased in the absence of flooding water (Fig. 3), and when the drainage time after application and the duration of dipping of Echinochloa oryzicola Vasing plants was less than 12hrs respectively, at the 2.5 leaf stage (Fig. 5, 6).
In conclusion, the flooding water depth and the period of exposure to cafenstrole could be important factors affecting the herbicidal activity. In particular, the management of the flooding water is the most important factor for obtaining a high herbicidal activity of cafenstrole.