The fungicidal properties of plant seed peptides from Heuchera sanginea (Hs-AFP1), Raphanus sativus (EA-AFP2), and Impatiens balsamina (Ib-AMP3) were determined for the nongerminated and germinated conidia of Aspergillus flavus and Fusarium moniliforme. These peptides were weakly lethal for germinated but not for nongerminated conidia of A. flavus. Both nongerminated and germinated conidia of F. moniliforme were susceptible to these peptides. Overall, F. moniliforme was more susceptible than A. flavus to the peptides. The peptides bound strongly to chitin, mannan, galactocerebrosides, and sphingomyelin. Binding results varied for ergosterol, cholesterol, and β1,3-glucan.