A herbicidal composition is provided, the composition comprising an aqueous suspension of microcapsules, the microcapsules having a capsule wall of a porous condensate polymer, wherein the microcapsules contain a solution of fluroxypyr in a rosin solvent system comprising rosin and/or a rosin derivative. There is also provided a herbicidal composition comprising microcapsules, the microcapsules having a capsule wall of a porous condensate polymer, wherein the microcapsules contain fluroxypyr and a solvent comprising rosin and/or a rosin derivative. A method of preparing a herbicidal composition is also disclosed, the method comprising the steps of providing a water immiscible phase comprising fluroxypyr and an isocyanate dissolved in a rosin solvent system comprising rosin and/or a rosin derivative； providing an aqueous phase comprising one or more surfactants； combining the water immiscible phase and the aqueous phase to form a dispersion of the water immiscible phase in the aqueous phase； adding to the resulting dispersion an amine, thereby forming microcapsules of polyurea containing droplets of the water immiscible phase； and curing the microcapsules.一種除草組合物，包含微膠囊的水懸液。此微膠囊具有多孔性縮合聚合物之囊壁。其中，微膠囊包含在松香溶劑系統中的氟草煙溶液，且松香溶劑系統含有松香和/或松香衍生物。本發明還提供一種包含微膠囊的除草組合物，此微膠囊具有多孔性縮合聚合物之囊壁。其中，微膠囊包含氟草煙以及含有松香和/或松香衍生物的溶劑。本發明還公開一種除草組合物的製備方法，包括以下步驟：提供含有氟草煙和異氰酸酯的水不混溶相，其中氟草煙和異氰酸酯係溶解在含有松香和/或松香衍生物的松香溶劑系統中；提供含有一種或多種表面活性劑的水相；將水不混溶相與水相合併以形成水不混溶相在水相中的分散液；在分散液中加入胺，藉以形成含有水不混溶相的液滴之聚脲的微膠囊；以及固化微膠囊。
