An aqueous horticultural microbicidal composition suspension comprising: Component (A), a specific oxime compound, or salt or N-oxide thereof Component (B), at least one kind selected from the group consisting of polyoxyalkylene alkyl ethers, polyoxyalkylene fatty acid esters, polyoxyalkylene sorbitan fatty acid esters, and silicone surfactants and Component (C), at least one kind selected from non-component (B) nonionic and anionic surfactants.