- Worldwide distribution. On maize and sweet corn. A minor disease.
- Spores from soil infect seedlings, grow inside and distort the ears, turning seeds into galls with millions of black spores. Smaller galls on leaves.
- Spread long distances is by spores on wind and seed, but also on people, animals, fodder, and machinery.
- Cultural control: do not replant on land where disease has occurred (spores stay alive for many years in soil); do not injure plants during cultivation; remove plants with signs of disease before galls burst; do not over fertilise plants; resistant varieties.
- Chemical control: treat seed with carboxin or thiram.
