(THIADIZOLE -1,2,3 YL-5) PROCEDE POUR LES PREPARER ET AYANT UNE ACTION DEFOLIANTE ET REGULATRICE SUR LA CROISSANCE

New 1,2,3-thiadiazole-5-yl-urea derivatives as plant growth regulating agents are provided, including processes for producing and using these compounds. The new 1,2,3-thiadiazole-5-yl-urea derivatives have the formula I in which R1 is an aromatic hydrocarbon group which may be substituted with one or more members of the group consisting of C1-C6-alkyl, halogen, C1-C6-alkoxy, nitro and trifluoromethyl and R2 is hydrogen, a monovalent metal or its metal equivalent, a substituted or unsubstituted C1-C6-alkyl, a C3-C6-alkenyl or alkinyl, a substituted or unsubstituted aryl- C1-C2-alkyl or the group aryl-C1-C2-alkyl wherein R3 is hydrogen, a substituted or unsubstituted C1-C10-alkyl, C2-C6-alkenyl, a C2-C6-alkenyl, an aryl-C1-C2-alkyl, a C3-C8-cycloaliphatic hydrocarbon group which may be substituted with one or more C1-C6-alkyl substituents, an aromatic hydrocarbon group which may be substituted with at least one of C1-C6-alkyl, halogen, C1-C6-alkoxy, nitro and trifluoromethyl, a substituted or unsubstituted heterocyclic hydrocarbon, C1-C6-alkoxy, C3-C6-alkenyl-or alkinyloxy, a substituted or unsubstituted aryloxy, and C1-C4-alkylthio or an arylthio or an amino group wherein R4 and R5 are each the same or different and are selected from the group consisting of hydrogen, C1-C6-alkyl, aryl or aryl substituted with one or more of the members selected from the group consisting of C1-C6-alkyl, halogen, C1-C6-alkoxy, nitro and trifluoromethyl.