Provided is a composition that enhances the effects of monosaccharides. The composition is a composition comprising a monosaccharide as an active ingredient thereof and comprising at least one or more assistants selected from a nonionic surfactant (excluding acetylene glycol-based surfactants, fluorine-based surfactants and silicone-based surfactants), an anionic surfactant (excluding lignin sulfonate), a cationic surfactant, an amphoteric surfactant, a water-soluble polymer, an amino acid, an amino sugar, a disaccharide alcohol and a salt, and is effective as an agricultural control composition against plant disease, particularly plant disease caused by fungi and plant disease caused by bacteria.