Seeds from ears of Zea mays infected by Gibberella zeae and Nigrospora oryzae frequently failed to show these fungi when germination took place in the absence of Pythium debaryanum. Diplodia zeae emerged from symptomless, infected seeds in both the presence and absence of P. debaryanum. Symptomless infection by Fusarium moniliforme evidently did not reduce germination in the absence of Pythium. The effect of F. moniliforme in the presence Pythium could not be tested because of inadequate controls. Symptomless infection by D. zeae, G. zeae, and N. oryzae always reduced the ability of seedlings to resist Pythium
