PROBLEM TO BE SOLVED: To provide an agricultural and horticultural water-dispersible agent having improved persistence of effect by improving rain resistance of germicidal active component mancozeb on phylloplane in a foliage application treatment, and having improved high-concentration water reducibility.SOLUTION: This agricultural and horticultural water-dispersible agent includes crushed particles containing mancozeb, zinc oxide and a lignin sulfonate, and has a particle size distribution in which the medium diameter of the particles is 0.1-3 &mu；m, and the maximum particle diameter is &le；10 &mu；m.
