Compositions and methods for indirectly reducing incidence of fungal pathogeninfection in a plant are disclosed,wherein the fungal pathogen may be Botrytis, Macrophomina, Rhizoctonia,Sclerotinia, or Verticillium. The compositions comprisepasteurized microalgae cells in an amount effective to reduce incidence of thefungal pathogen in a plant compared to a substantiallyidentical population of untreated plants. The composition treatment caninclude at least one microalgae such as Chlorella,Aurantiochytrium acetophilum HS3 99, Galdieria, Scenedesmus, Haematococcus,Isochrysis, Spirulina or any combination thereof. Where thecomposition comprises a combination of a first microalgae and a secondmicroalgae, the composition may consist of a ratio of 25:75,50:50: or 75:25.
