FUNGICIDIC COMPOSITION

1,3,4-Oxadiazole derivatives, are disclosed which correspond to the formula in which R represents the phenyl radical; a phenyl radical which is substituted by 1 to 5 identical or different substituents chosen from amongst halogen atoms, the nitro radical, the cyano radical, the hydroxy radical, alkyl radicals containing from 1 to 4 carbon atoms, alkoxy radicals, the alkyl part of which contains from 1 to 4 carbon atoms, alkenyl radicals containing from 2 to 4 carbon atoms, alkenyloxy radicals containing from 2 to 4 carbon atoms, alkenyl radicals containing from 2 to 4 carbon atoms, alkynyloxy radicals alkynyl part of which contains from 2 to 4 carbon atoms, alkylsulphonyl radicals, the alkyl part of which contains from 1 to 4 carbon atoms, alkylthio radicals containing 1 to 4 carbon atoms dialkylamino radicals, of which each of the identical or different alkyl parts contains from 1 to 4 carbon atoms, the carbamoyloxy radical which is optionally substituted by 1 to 2 alkyl radicals containing from 1 to 4 carbon atoms, or the trifluoromethyl radical, a phenyl radical which is substituted by a divalent alkylenedioxy radical in which the alkylene part contains from 1 to 4 carbon atoms, or a naphthyl radical or a heterocyclic radical comprising from 5 to 7 chain members and containing, as the heteroatom, a nitrogen, sulphur or oxygen atom, these radicals being optionally substituted by 1 to 3 identical or different substituents chosen from amongst halogen atoms, and alkyl, alkoxy or alkylthio radicals in which the alkyl part contains from 1 to 4 carbon atoms. These compounds can be used as agricultural fungicides.