There is disclosed a method of controlling unwanted vegetation in fallow wheatland by the application of a substituted thiadiazol-2-ylurea following the harvesting of the wheat crop.
Novel 1,3,4-thiadiazol-2-ylureas characterized by an hetero-ring sulfamoyl group at the 5-position, and by small alkyl or alkoxy groups on the urea nitrogens. The hetero-ring groups are 5- and 6-membered rings containing an oxygen, sulfur, or nitrogen atom, and may optionally be linked to the sulfamoyl nitrogen by a methylene group. The novel compounds are effective pre- and postemergence herbicides.