The invention relates to methods for controlling mycotoxin production in field populations of heterothallic and homothallic filamentous fungi through application of biocontrol compositions comprising selected strains of the heterothallic and homothallic filamentous fungi, the selected strains having a lineage of low mycotoxin production or no mycotoxin production and having opposite mating types (heterothallic) or both mating types (homothallic) (e.g., MAT1-1, MATT-2).