Technical Abstract: Gallic acid, from hydrolysable tannins in the pellicle of walnut kernels, dramatically inhibit biosynthesis of aflatoxin by Aspergillus flavus. Additional research using other antioxidant phenolics showed similar antiaflatoxigenic activity. Treatment of A. flavus with butyl peroxide resulted in an almost doubling of aflatoxin biosynthesis compared to untreated cohorts. Thus, antioxidative response systems are potential molecular targets for control of A. flavus. For example, the S. cerevisiae sod2 delta mutant was highly sensitive to treatment by certain phenolics and strobilurins/antimycin A, fungicides which inhibit complex III of the mitochondrial respiratory chain. Verification of stressing this system in the target fungus, A. flavus, was shown through complementation analysis, wherein the mitochondrial superoxide dismutase (Mn-SOD) gene (sodA) of A. flavus in the ortholog mutant, sod2 delta, of S. cerevisiae, relieved phenolic induced stress. Identifying the antioxidative response systems in other pathogens could improve methods for fungal control.