When disease pressure is very high, this resistance may not be enough. Plant breeders specifically breed for resistance to certain diseases, and high levels of resistance are available for these diseases. Check with your seed company representative for specific information on the seed you buy. Following is a brief summary of the types of resistance you can expect to find in common hybrids and varieties. Gray leaf spot of corn .
Resistance is polygenic.
Most hybrids do not have a high level of resistance, but in recent years, some moderately resistant hybrids have become available. Northern corn leaf blight . Both single-gene and polygenic resistance are available, but the polygenic type is more common. There are many hybrids available with good resistance to northern leaf blight, and most seed companies publish ratings. Eyespot of corn .