Pyrimethanil is a pyrimidine amine fungicide, which has leaf penetration and root systemic activity, and has excellent control effects on gray mold of grapes, strawberries, tomatoes, onions, kidney beans, cucumbers, eggplants and ornamental plants. It also has good control effect on apple black disease of fruit trees. Foliar application can prevent Botrytis cinerea on grapes, fruit trees, vegetables and other crops. The fungicide has high activity against all strains of Botrytis, and has no cross-resistance to Botrytis control agents currently on the market.