Disclosed herein is a pest control composition for agricultural or horticultural use comprising as the active ingredients one or more 4-(3-butynyl)aminoquinazoline derivatives represented by general formula [I] wherein R4 taken together with R3 and two carbon atoms of the pyrimidine ring forms a benzene ring, together with one or more pest control compounds for agricultural or horticultural use selected from for example chlorothalonil, chinomethionate, iminoctadine albesilate, triflumizol, tebuconazole, difenoconazole, triadimefon, fenpropimorph, azoxystrobin, pyraclostrobin, trifloxystrobin, kresoxim-methyl, cyflufenamid, penthiopyrad, flutianil, quinoxyfen, thiophanate-methyl, diflumetorim, acibenzolar-S-methyl, manzeb, cyazofamid, amisulbrom, cymoxanil, kresoxim-methyl, azoxystrobin, metalaxyl M, mandipropamid, benthiavalicarbisopropyl, dimethomorph, acephate, imidacloprid, tolfenpyrad, acrinathrin, flonicamid, and pyrifluquinazon. Also disclosed are methods of treating or preventing microbial infection or insect infestation in plants using these compositions.
