Larvae of the corn earworm,Heliothis zea(Boddie), and the fall armyworm,Spodoptera frugiperda(J. E. Smith), were reared under laboratory conditions on a diettreated withAspergillus flavusLink orA. parasiticusSpeare. Results indicate A.parasiticusis more toxic to the corn earworm than A.flavuswhen larvae are not transferred daily. The larval stage of the corn earworm sustains more toxic effects than either the pupal or adult stages. When larvae were transferred to fresh diet daily after initial exposure to treated diet, neither the corn earworm nor the fall armyworm showed any significant pathogenic effects (P= 0.01). Overall, toxicity was more evident than pathogenicity.