A benzothiazole derivative represented by the general formula: ##STR1## wherein X represents --NHR, --R or --OR group in which R is a lower alkyl, cycloalkyl, aryl or substituted aryl group; Y represents a lower alkyl, alkenyl, alkyloxycarbonylalkyl, benzyl or substituted benzyl group; and Z represents a lower alkoxy group or a hydrogen atom. This compound is useful as an active ingredient of an agricultural and horticultural fungicide.