The present invention aims to provide a microcapsule composition that enables reduction or prevention of injury of useful plants caused by pyroxasulfone, a production method therefor, an agrochemical formulation containing the same, and a weed control method. A microcapsule composition including pyroxasulfone and a polyester block copolymer encapsulated therein, an agrochemical formulation containing the same, and a weed control method are provided. A method of producing the microcapsule composition, the method including: an emulsifying dispersion step of performing high-speed stirring of pyroxasulfone crystal particles, a polyester block copolymer, isocyanate, oily phase, and aqueous phase at a peripheral speed of 10,000 to 50,000 mm/s to allow emulsifying dispersion of the oily phase in the aqueous phase, to form emulsion particles of the oily phase； and a membrane formation step of forming a membrane on at least the surface of the emulsion particles of the oily phase formed by the emulsifying dispersion step； is also provided.本發明為提供一種可減輕或防止因派羅克殺草碸(Pyroxasulfone)導致之有用植物的藥害之微膠囊組成物及其製造方法、含有該組成物之農藥製劑及雜草防除方法。本發明為一種微膠囊組成物、含有該組成物之農藥製劑及雜草防除方法，其特徵為封入派羅克殺草碸與聚酯嵌段共聚物。又，為一種微膠囊組成物之製造方法，其特徵為包含：藉由將派羅克殺草碸之結晶粒子、與聚酯嵌段共聚物、與異氰酸酯、與油性相、與水性相以周速10,000～50,000mm/s進行高速攪拌，乳化分散前述油性相於前述水性相中，形成油性相的乳化粒子之乳化分散步驟、與在前述乳化分散步驟所形成之油性相的乳化粒子的至少於表面形成膜之膜形成步驟。
