Abstract: 1,2,3-thiadiazole-5-carboxylic acid derivatives having herbicidal and growth regulating activity and having the formula ##STR1## in which R.sub.1 is hydrogen or is alkyl of which the chain may be interrupted in one or several places by oxygen or sulfur or which may be substituted by halogen and in whichX is(a) --Y--R.sub.2, wherein R.sub.2 is hydrogen, alkyl which may be substituted, aryl which may also be substituted, aryl-C.sub.1 -C.sub.2 -alkyl which may also be substituted, or a univalent metal equivalent and wherein Y is oxygen or sulfur, or(b) wherein X constitutes the residue ##STR2## wherein R.sub.3 and R.sub.4 may be the same or different and have the meaning further defined in claim 1 of the accompanying specification.The compounds are soil- or leaf-applicable herbicides with a high activity against seed weeds and resistant weeds.

Abstract: 1,2,3-Thiadiazole-5-yl-urea derivatives of the formula ##STR1## in which R.sub.1 is hydrogen or alkyl of 1 to 5 carbon atoms, R.sub.2 is hydrogen or alkyl from 1 to 5 carbon atoms which latter may also have at least one oxygen or sulfur atom interposed in the carbon chain and wherein R.sub.3 is a heterocyclic hydrocarbon residue in which at least one nitrogen atom is present in the ring, which residue may also be substituted by the same or different substituents comprising alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms, halogen, nitro or trifluoromethyl. The compounds are effective as agents for growth retardation and defoliation of plants.The invention also comprises a process of making the product and compositions in which the products are the, or one of the, effective agents.

Abstract: The specification discloses the use of compounds having the formula: ##STR1## wherein R is a possibly substituted aromatic hydrocarbon radical as insecticides and ovicides.

Abstract: 1,2,3-Thiadiazole-5-yl-urea derivatives of the formula ##STR1## in which R.sub.1 is hydrogen or alkyl of 1 to 5 carbon atoms, R.sub.2 is hydrogen or alkyl from 1 to 5 carbon atoms which latter may also have at least one oxygen or sulfur atom interposed in the carbon chain and wherein R.sub.3 is a heterocyclic hydrocarbon residue in which at least one nitrogen atom is present in the ring, which residue may also be substituted by the same or different substituents comprising alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms, halogen, nitro or trifluoromethyl. The compounds are effective as agents for growth retardation and defoliation of plants.The invention also comprises a process of making the product and compositions in which the products are the, or one of the, effective agents.