Diseases of Maize 1. Smut Caused by fungus: Ustilago maydis Most widely recognized maize disease Symptoms: Complete barrenness in most plants Result: Reduced grain development ~30% yield loss

Appears as galls on both the ear and stalk White at first, but develop into dark lesions with dark spores inside the whitish membrane. Galls break and scatter spores More likely to attack vigorous growing plants Not poisonous to livestock and man.

Smut organism lives in the soil Seed disinfection or treatment is ineffective, except to prevent spread to new fields Treatment: Crop rotation Don’t spread manure infested with smut on fields. Plant resistant varieties.

Control Rotate field out of maize for 2 years Used treated seed to prevent infestation into other fields

2. Leaf Blight Infection of the lower leaves Boat-shaped, grayish lesions Spread to other leaves in cool, damp weather Can cause leaf death

Control Plant resistant varieties. Crop rotation.