Smut
Ustilago maydis (corn), Tilletia spp. (wheat bunt), Ustilago spp.
Overview
A group of fungal diseases primarily affecting grains and grasses, producing masses of dark, powdery spores that replace plant tissues, particularly in flowers and developing seeds.
Symptoms
Dark, powdery masses of spores replacing kernels, flowers, or other plant parts. Corn smut produces large, silvery-white galls that rupture to release black spores. Covered smut replaces grain heads with spore masses enclosed in a membrane.
Environmental Conditions
Variable
Prevention
Plant resistant varieties. Use treated seed. Rotate crops. Remove and destroy smut galls before they rupture. Avoid excessive nitrogen fertilization.
Management
Remove smut galls from corn before they mature. Fungicide seed treatments for small grains. Crop rotation. Destroy infected plant residues. Hot water seed treatment for some crops.