Genetic studies of resistance to leaf feeding by the European corn borer, Ostrinia nubilalis (Hübner), in grain corn, Zea mays L., were conducted using an 8 × 8 diallel cross. In the eight inbreds used, the additive component appeared to be the most important in determining resistance to leaf feeding. There was only one group of genes showing some degree of dominance. Heritability was estimated at 40%. Possible reasons for the significance of the environmental component were discussed. The feasibility of developing resistant lines or varieties in Quebec was also considered.
Trials were conducted in 1997 and 1998 to determine if there is a range of resistance to European corn borer [Ostrinia nubilalis (Hübner)] (ECB) in commercially available processing sweet corn (Zea mays L.). Twelve processing corn cultivars were tested in 1997 and 18 cultivars in 1998. About 40 first instar larvae of colony-reared ECB were used to infest plants in both whorl and silking stages of growth. At harvest, plants infested at the whorl stage were evaluated for numbers of larvae and larval tunnels, and length of larval tunnels. Plants infested at the silking stage were evaluated for number of larvae per ear and were rated for ear damage using a 9-point scale. Resistance rankings among cultivars were consistent between years and between silk- and whorl-infested plants. We conclude that there is a substantial range of resistance already present in processing sweet corn cultivars, and that resistance is probably a combination of both exclusion and suppression of feeding. Our findings have two immediate uses: incorporation into existing IPM programs and incorporation of identifiable resistance bearing cultivars into a long-term breeding program for resistance to ECB in sweet corn.
Corngrass 1 of Maize (Zea mays L.) Delays Development of Adult Plant Resistance to Common Rust (Puccinia sorghi Schw.) and European Corn Borer (Ostrinia nubilalis Hubner)