NOVELTY - A pyrazole-4-carboxamide derivative (I), is new.    USE - New pyrazole-4-carboxamide derivative is used in agent for agricultural and horticultural for preventing and controlling microbial diseases (claimed), preferably fungal disease, and various plant diseases. The fungal disease includes powdery mildew caused by Ascomycetes, rust fungi disease caused by Basidiomycetes, downy mildew caused by Rhizoctonia solani, rice blight caused by Pyricularia grisea, leaf spot caused by Cochliobolus miyabeanus, sheath blight caused by Thanatephorus cucumeris, bakanae disease caused by Gibberella fujikuroi, rice blast disease caused by Claviceps virens, red mold disease caused by Gibberella zeae, Fusarium avenaceum, F.culmorum and Monographella nivalis, snow blight caused by Pythium, Typhula, M.nivalis and Myriosclerotinia borealis, eye spot disease caused by Pseudocercosporella herpotrichoides, leaf blight caused by Septoria tritici, small black speck disease caused by Diaporthe phaseolorum, scab disease caused by Elsinoe fawcettii, brown rot disease caused by Phytophthora citrophthora, green mold disease caused by Penicillium digitatum, blue mold disease caused by P.italicum, early blight disease caused by Botryosphaeria berengeriana, red spot disease caused by Gymnosporangium yamadae, canker caused by Mycosphaerella melonis, wilt disease caused by F.oxysporum, leaf mildew of tomato, early blight of potato caused by Alternaria solani, and white rust of Chrysanthemum caused by P.horiana.    ADVANTAGE - The pyrazole-4-carboxamide derivative causes no drug induced damage to crops, is environmentally-friendly, cost-effective and safe to crops and controls diseases at very low dose.    DETAILED DESCRIPTION - A pyrazole-4-carboxamide derivative of formula (I), is new.    R1=1-6C alkyl;    R2=1-6C alkyl or 1-6C haloalkyl;    R3=H or halo;    R4=H, halo, 1-6C alkyl or 1-6C haloalkyl;    Ar'=phenyl optionally substituted by halo, 1-6C alkyl, 1-6C alkoxy, 1-6C haloalkyl, 1-6C haloalkoxy or 1-6C alkylthio, pyridyl optionally substituted by halo, 1-6C alkyl, 1-6C alkoxy or 1-6C haloalkyl, thienyl optionally substituted by halo or 1-6C alkyl or furyl optionally substituted by 1-6C alkyl;    X=H, halo, 1-6C alkyl or 1-6C haloalkyl;and    n=1-4.    An INDEPENDENT CLAIM is included for manufacture of pyrazole-4-carboxamide derivative (I).