The present invention provides a process for producing co-crystal comprising thiophanate-methyl and triazole based compound and a process for producing an agricultural and horticultural chemical formulation in which the co-crystal is used as raw materials. For example, the agricultural and horticultural chemical composition of the present invention is obtained by keeping the temperature of the suspension containing thiophanate-methyl, triazole based compound, surfactant, antifoaming agent and water at 60 ℃, obtaining a sol containing the co-crystal by a method comprising stirring at 0.1 to 1.0 of the degree of mixing, and adding the supplementary components such as silica, calcium carbonate, and the like, to the sol.根據本發明，提供一種由甲基多保淨(thiophanate-methyl)與得克利(tebuconazole)等三唑系化合物所構成之共結晶之製造方法及使用該共結晶作為原材料之農園藝藥劑製劑之製造方法。作為本發明之農園藝藥劑組成物之一例，係藉由包括如下步驟之方法獲得：藉由包括將含有甲基多保淨、得克利等三唑系化合物、界面活性劑、消泡劑及水之懸浮液於懸浮液溫度保持於60℃、混合度0.1~1.0之條件下進行攪拌之步驟之方法而獲得含有共結晶之溶膠，於該溶膠中添加二氧化矽、碳酸鈣等輔助成分。
