The life cycle, population dynamics and sampling plan of the corn borer were investigated. The insect was found to have five instars instead of six as previously reported. Insects that were reared on field corn had longer life cycles with corresponding bigger size of individuals and higher fecundity than those reared on cornstalk, bush sitao, and artificial diet in the laboratory. The second, third, fourth leaves were significantly preferred for oviposition by the moths. The biology of the first generation corresponded with the vegetative growth and whorl stage of the corn plant and the biology of the second generation with pollen shedding of the tassel and ear formation.