Sorghum kernel smut

Systematic position and pathogen type: Sporisorium sorghi is a fungal pathogen classified within the kingdom Fungi, phylum Basidiomycota, and class Ustilaginomycetes. It is an obligate parasite, which functions as an internal systemic pathogen that colonizes the host plant tissues from the seedling stage until the maturation of the panicle.

Diseases and host crops: This organism causes a condition known as kernel smut (or covered smut) of sorghum. It specifically targets Sorghum bicolor and related species, including Sudan grass. The pathogen replaces the grains within the panicle with sacs filled with black teliospores, effectively destroying the yield potential of the infected spikes.

Biology and life cycle: The life cycle begins primarily with teliospores adhered to the seed surface. When the seed germinates, the spores germinate as well, producing basidiospores that penetrate the young coleoptile. The mycelium grows systematically inside the plant, reaching the inflorescence primordia, where it replaces the floral tissues with fungal spore masses during the development of the grains.

Conditions for development and harmfulness: The development of the fungus is favored by moderate soil temperatures and adequate moisture during the emergence of the crop. Infection rates increase when planting occurs in cool, moist soil conditions. Beyond direct grain loss, the presence of smut reduces the overall quality of silage and fodder, making the harvest unsuitable for livestock feed.

Control and management measures: Effective control is achieved primarily through the application of systemic fungicides as seed treatments. Chemical control is highly effective because the pathogen is seed-borne. Other integrated pest management strategies include selecting resistant hybrids, ensuring planting is done in warm, well-draining soil to promote rapid seedling emergence, and strictly avoiding the use of seed from contaminated fields.