Abstract: A process for destroying weeds in sorghum crops which comprises applying to the area of the growing crop or to the crop area before the crop emerges, 2,4-diamino-6-chloro-5-methylthio-pyrimidine or a mixture of the two isomeric compounds 2,4-diamino-6-chloro-5-methylthio-pyrimidine and 4,6-diamino-2-chloro-5-methylthio-pyrimidine in which 2,4-diamino-6-chloro-5-methylthio-pyrimidine is preponderant, the rate of application of the above compound or mixture being from 300 g/ha to 4,500 g/ha. Herbicides may be simultaneously applied.

Abstract: Heterocyclic compounds of the general formula: ##STR1## wherein: R.sub.1 represents alkyl, haloalkyl, alkenyl, haloalkenyl, arylalkyl, arylhaloalkyl, cycloalkyl, halocycloalkyl, aryl, haloaryl, alkoxyalkyl or haloalkoxyalkyl;X.sub.1 is chlorine, bromine, or fluorine;X.sub.2 and X.sub.3 are hydrogen, chlorine, bromine or fluorine;A represents oxygen or sulphur, S-O ##STR2## or N-R.sub.8 ; R.sub.8 is hydrogen, alkyl, haloalkyl, hydroxyalkyl, alkoxyalkyl, arylalkyl, aryl or ##STR3## B represents ##STR4## m is 0, 1 or 2; n and p are 0 or 1;R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.7, R'.sub.2, R'.sub.3, R'.sub.4, R'.sub.5 are the same or different and are hydrogen, alkyl, alkoxyalkyl, haloalkyl, or hydroxyalkyl;and Y and Z are the same or different and are hydrogen, halogen, alkyl or alkoxy.These compounds are used as antidotes against herbicides.