Abstract
Infections of Nosema pyrausta (Paillot 1927) Kotlan 1928, in egg masses of Ostrinia nubilalis (Hübner) used to artificially infest maize did not significantly decrease the ability of the infected larvae to migrate to adjacent plants. When 25% of the egg masses placed on the plants contained N. pyrausta, the resulting larvae had an incidence and an intensity of infection significantly greater than those of the controls. If 100, 75, 50, and 25% of the infesting eggs were infected by N. pyrausta, the number of larvae per plant were reduced by 72.0, 44.0, 29.3, and 38.7% respectively. N. pyrausta was transmitted via contaminated frass. The result was a reduction in populations of O. nubilalis larvae.