| 摘要 |
Heterocyclic compounds R = -O, -S or Se X = cyano or thiocarbamoyl n = 0, 1, 2 or 3 Y = Cl, Br, nitro, alkyl (pref. C1-C2), amino, cyano or thiocarbamoyl Compounds with greatest herbicidal activity when X is in posn. 4 or 7 and a) n = 1 and Y = cyano or thiocarbamoyl; b) n = 2, one of Y = methyl, the other Y = cyano or thiocarbamoyl. (I) have pre- and post emergence herbicidal activity and may be used esp. in rice fields or as defoliating agents. (I) is therefore applied to the upper soil, pref. the upper 5-8 cm of the rice fields before flooding. After flooding the rice seedlings are planted. An application of 1/2-2 kg/ha is sufficient for killing weeds without damage to the rice. |
