Sphacelotheca reiliana
Nature of damage
- The infection is systemic: the fungus penetrates the seedlings and grows inside the plant without showing symptoms, until the tasseling and silking stages.
- Infection of the tassel also leads to reduced pollen production.
Signs
- Abnormal development of the tassels, which become malformed and overgrown
- Black masses of spores that develop inside individual male florets
- Masses of black spores in place of the normal ear, leaving the vascular bundles exposed and shredded
Factors favoring development
- Dry and cool weather at the start of the season favors the disease as maize seedling growth is slow.
- Later in the season dry and warm conditions (21-30°C) favor disease severity.
- Soil moisture content of 15-25% W/w is optimal for seedling infection.
- Head smut has been recorded as being more severe under nitrogen deficiency.
Geographic distribution
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Worldwide distribution
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