Effect of Plant Height and the Yellow-Green Gene in Maize on Leaf Feeding by First-Generation European Corn Borers (Lepidoptera: Pyralidae)1

We detennined the level of the larval Ostrinia nubilalis Hübner establishment on maize, Zea mays L., of different heights and the effect of the recessive yellow-green (yg2) gene on larval establishment. The yg2 gene was incorporated in the WF9 line by three and four backcrosses. Larval establishment was very poor on small plants (30 cm extended leaf height) of inbred lines CL31A and WF9, compared with plants of 45 and 63 cm extended leaf height; infestations were made 20, 32, and 45 days after egg hatch for the 30-, 45-, and 63-cm plants. Larval survival, however, was very high on small plants that included the recessive yg2 gene compared with the WF9 types; both types were physiologically similar in age at time of infestation (45 days after egg hatch). Hence, poor establishment of first-generation, O. nubilalis larvae was due to physiological plant age rather than plant height.