RAPID METHOD OF EVALUATING MAIZE FOR SHEATH-COLLAR FEEDING RESISTANCE TO THE EUROPEAN CORN-BORER (LEPIDOPTERA, PYRALIDAE)

An internal visual rating method of evaluating Zea maize L. for sheath-collar feeding resistance to Ostrinia nubilalis (Hubner) is presented. The method involves determining the number of stalk subsections containing larval tunneling almost-equal-to 60 d after artificial infestation of plants. The subsections examined range from four nodes above the ear node to four nodes below the ear node. Comparisons were made between internal visual ratings and two previously described methods: centimeters of larval tunneling within the stalk and sheath-collar damage ratings. Correlations between the various methods showed that the internal visual rating can be used to evaluate maize genotypes for resistance. Also, the internal visual rating is almost-equal-to 40% faster than determining centimeters of tunneling.