A system for reducing the incidence or severity of fungal infection of a plant, comprising a chemical fungicide component, which may be provided by foliar or root (soil or liquid nutrient) application, together with an antifungal plant defensin not in nature expressed in the plant being protected or expressed in lower amounts or in different tissues, provides synergistic improvement in protection against infection by a plant pathogenic fungus which is susceptible to the defensin and the fungicide. The fungicide can be a strobilurin or a triazole, and the defensin can be selected from a wide range of known defensins, for example, NaD1 and others, or it can be a chimeric defensin engineered for low toxicity to the plant. The defensin can be provided as a protein formulation, optionally together with the fungicide, or it can be provided by recombinant expression in the plant to be protected from fungal infection.