Sorghum ergot

Claviceps africana is a fungal phytopathogen within the genus Claviceps, primarily responsible for the development of sorghum ergot. This fungus specifically targets the ovaries of sorghum plants, disrupting the fertilization process and transforming the floral tissues into structures known as sphacelia, which eventually produce spores.

The disease is characterized by the secretion of "honeydew," a sugary, sticky liquid that covers the flowering panicles. This honeydew contains high concentrations of conidia, which facilitate the rapid spread of the fungus to neighboring plants via wind, rain splash, or insect vectors, leading to secondary infection cycles during the flowering stage.

The life cycle of the pathogen is highly dependent on specific environmental conditions, particularly high relative humidity and moderate temperatures during the pollination period. When these conditions align, the fungus colonizes the ovary tissue, eventually producing a characteristic white to cream-colored mass that replaces the grain kernel entirely.

The economic impact of Claviceps africana is significant, leading to severe yield reductions and contamination of the harvested grain. The infected grain often contains toxic alkaloids, which pose serious health risks to livestock if used in feed. Consequently, infected crops often face rejection in commercial grain markets.

Management and control strategies are essential for minimizing the impact of sorghum ergot:

• Selecting and planting resistant sorghum hybrids.
• Timing planting dates to avoid favorable environmental conditions for infection during the flowering phase.
• Removing collateral host plants or wild grasses that harbor the fungus in the vicinity of fields.
• Implementing fungicide applications at the onset of flowering when weather forecasts predict high-risk conditions for infection.