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; andZ represents a lower alkoxy group or a hydrogen atom.This compound is useful as an active ingredient of an agricultural and horticultural fungicide.