Peanut smut

The causal agent of peanut smut is the soil-borne fungus Thecaphora frezii, a member of the basidiomycetes. This pathogen is highly specialized, specifically targeting the peanut plant and systemic infection, resulting in the replacement of seed tissue with fungal sori.

The primary host for this disease is the peanut (Arachis hypogaea). Peanut smut has emerged as a significant economic threat, particularly in major producing regions, where it can drastically reduce both the quantity and quality of the yield.

Symptoms are often internal and become apparent only during harvest or pod shelling. The diagnostic sign is the transformation of peanut kernels into dark, dusty masses of teliospores. The pods may appear slightly stunted or deformed, but the destruction of the seed inside is the definitive indicator of infection.

The disease cycle is driven by the survival of teliospores in the soil for several years. Dispersal occurs through contaminated soil attached to farm equipment, infected seed lots, and movement of soil by water or wind. The fungus typically infects the plant during the early stages of pod formation when environmental conditions are conducive to spore germination.

Effective management strategies rely on integrated pest management practices:

• Strict use of high-quality, certified, and fungicide-treated seeds.
• Implementation of long-term crop rotation cycles to starve the pathogen in the soil.
• Sanitation measures to prevent the spread of soil and crop residues between fields.
• Monitoring fields for symptomatic pods to prevent further distribution of the inoculum.