Northern Corn Leaf Blight
Symptoms:
- Lesions are gray to green in color, cigar shaped, and (3 - 15 cm) long
- Lesions may contain prominent, dark areas of sporulation as they mature
- The length or size of lesions may vary with their different reactions to resistant genes within corn hybrids
Pathogen Involved:
- Setosphaeria turcica (a fungus)
- Overwinters on corn leaf debris.
- Races of this pathogen are grouped according to their virulence to resistant Ht genes
- Race 1 is not considered important, because of use of the Ht1 gene for resistance in most commercial corn hybrids
- Race 2 may infect commercial corn hybrids that only have the Ht1 gene for resistance .
Time of Occurrence:
- Occur at silking or after silking of corn
- Most prevalent during warm and prolonged periods of moisture during the growing season
- Significant grain losses can result if this disease begins before silking
Conditions Favoring Disease:
- Moderate temperatures of 66 - 80 F
- Long periods of dew
Disease Management:
- Use resistant hybrids
- Fungicides may be warranted during the early stages of this disease for seed corn