PURPOSE: To obtain the title composition, containing Sumilex(R) and Prumycin(R) as active ingredients, having excellent synergistic effects, capable of exhibiting high controlling effects by foliar spraying and effective against chemical-resistant germs without exerting phytotoxicity on plant bodies, etc., and useful as an agricultural and horticultural germicide.

CONSTITUTION: A germicidal composition containing Sumilex(R) [=3-(3,5- dichlorophenyl)-5-methyl-5-vinyl-2,4-oxazolidione] used as an agricultural and horticultural germicide and Prumycin(R) (=4-N-D-alanyl-2,4-diamino-2,4- dideoxyarabinose) which is an antibiotic substance effective in use thereof for various agricultural and horticultural crops as active ingredients. The mixing ratio thereof is 20:1W1:1 weight ratio of the former to the latter and a pharmaceutical is prepared by adding a carrier or adjuvant so as to contain 0.1W99.9wt.% active ingredients by a conventional method for preparation thereof. The above-mentioned composition is applied in an amount of 10W300g/10a amount of the active ingredients in use thereof as an agricultural and horticultural germicide.