FIELD: agriculture. SUBSTANCE: the described composition contains a) imidazole compound of formula (1) 
, where R - the lowest alkyl or alkoxygroup, n = 1, as active ingredient and b) one inorganic phosphorus compound chosen out of the group including phosphorus acid, phosphorous acid and their salts, or one fungicide for phycomycetes chosen out of the group: methyl-(E)-2-2-[6-(2- cyanphenoxy)pyrimidine-4-iloxy] phenyl-3- methoxyacrylate, methyl-(E)-methoxyimino[alpha-otolyloxy)-o-tolyl] acetate, 3- anilino-5-methyl-5-(4- phenoxyphenyl)-1.3-oxazolidine-2.4-dion, 1-(2-cyano-2- methoxyiminoacetyl)-3-ethylurea, tetrachloroisophthalonitrile, methyl-N-(2- methoxyacetyl)- N-(2.6-xylyl)-DL-alaninate, (E, Z)-4-[3-(4-chloro-phenyl)- 3-(3.4- methoxyphenyl)acryloil] morpholine, inorganic copper-containing fungicide, aluminium tris- (ethylphosphonate) as active ingredient, or c) distributing agent as activity-enhancing ingredient as silicone surfaceactive substance or mineral oil, where component a) and phosphorus compound are at 1:50 - 5:1 weight ratio and fungicide is at 1: 2000 - 2000-1 weight ratio, or a) and c) are at weight-volume ratio (kg/l) ranged 1:5000 - 1:0.25. It is, also, described method for preventing fungous diseases in cultivated plants including application of the above-mentioned composition upon plants and method for enhancing agent's action in suppression of fungous diseases and containing the above-mentioned compounds of formula (1) and distributing agent c) at weight/volume ratio (kg/l) being 1: 5000 - 1:0.25. EFFECT: increased curative and prophylactic action upon cultivated plants. 11 cl, 35 ex, 46 tbl
