Gray Leaf spot
scouted Sept. 24, 2025
- Scientific Name
- Cercospora zea-maydis
- Background
- Corn in Iredell County was being scouted, and it was observed that 65% of the field was affected by a blight and by marginal blackening on the entire plant. A sample was sent to the PDIC for diagnosis., The side is a dry and sunny site.
- Conclusion
- The lesions were identified as Gray leaf Spot of corn, caused by the fungus Cercospora zea-maydis. This disease is present in almost all growing seasons, but it only causes economic losses if the conditions favor disease development. There are fungicides labeled for gray leaf spot, there are resistant hybrids available, and crop rotation and tillage reduce the survival of the fungus. It's also important to note that the blackening observed is likely due to secondary fungal growth, like Cladosporium colonizing dead or dying tissue, rather than it being directly caused by the primary leaf pathogens.
- Resources
