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.