Grey leaf spot (Cercospora zeae-maydis
Symptoms are similar to Southern leaf blight but the spots are much narrower. They are initially light brownish in colour, and with age they bleach to ashen grey surrounded by narrow light-brownish border. When wet, spore mass is formed on the spots with a light shade. This disease is favoured by prolonged periods of high relative humidity. It can cause yield losses of 30 to over 50%.
- Use resistant varieties if available.
- Practise field sanitation. It helps in reducing the inoculum (infection) source.