Area of impact: Ears, leaves, stalk and tassels

Description: Galls are white or silvery at first later turning into dark masses of spores.

Pathogen involved: Ustilago maydis (a fungus)

Timing/Conditions: Strikes at anytime during the season but wounding of young plants (from hail wind etc.) and rainy wet weather may increase risk.

Contributing factors: Poor pollination and excess nitrogen fertilization. Overwinters in crop debris or soil.

Management practices: Plant resistant hybrids, rotate crops and maintain fertility.