Gray Leaf spot
scouted Aug. 27, 2025
- Scientific Name
- Cercospora zea-maydis
- Background
- Corn in Northampton was being scouted at halfway through the milk stage and heading for black layer, and it was observed that 95% of the field was affected by general reddening with scabby lesions and speckling/stippling. The site is sunny. A sample was submitted to the PDIC for diagnosis.
- 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.
- Resources
