A microbicidal composition having at least four components. The first component is 2-25 wt % of 2,2-dibromo-3-nitrilopropionamide. The second component is 2-30 wt % water. The third component is 5-30 wt % of an aliphatic compound having 2-6 hydroxyl groups. The fourth component is 20-70 wt % of a glycol solvent.