Hatching and dispersal of early instars ofChilo partellus(Swinhoe) on maize were studied in the field at different initial densities. Approximately 20% of the larvae remained on the oviposition plant 1 wk after hatching. Dispersing larvae were about 25% of the original number of eggs. On average, 50% of the potential larvae (eggs) were lost within 14 d after oviposition. The mean number of plants infested from each oviposition plant varied from 2.26 to 4.22. The mean dispersal distance in the field for the larvae was ≈30–70 cm. Fewer new plants were infested by dispersing larvae as the initial density of egg batches increased; this may be due to competition for resources. No density dependence of mortality of egg and larvae due to natural enemies or other factors was demonstrated.