A pest control composition for agricultural or horticultural use, characterized by comprising, as the active ingredients, one or more kinds of 4-(3-butynyl)aminopyrimidine derivatives represented by general formula [I] [wherein, for example, R1 is selected from among phenyl, a hydrogen atom, etc. R2 represents a hydrogen atom R3 represents a hydrogen atom and R4 represents a hydrogen atom], said derivatives having excellent controlling effect on pests, in particular, agricultural or horticultural pests, together with one or more kinds of pest control compounds for agricultural or horticultural use selected from among a bactericidal compound for agricultural or horticultural use, a biological bactericide and/or an insecticidal/acaricidal/nematicidal compound for agricultural or horticultural use. By the combined use of the aforesaid derivative with a conventional compound having bactericidal activity and/or a conventional compound having insecticidal activity, the usage of a pest control, in particular, a 4-(3-butynyl)aminopyrimidine derivative that is useful as a pest control for agricultural or horticultural use, can be reduced and the bactericidal activity or insecticidal activity can be enhanced.
