‘Covered smuts’ disease in Barley is caused by Ustilago hordei, a biotrophic smut fungus that infects seeds systemically, replacing kernels with spore masses covered by a persistent membrane at heading stage. This distinguishes it as the covered smut pathogen specific to barley. The correct answer is option (4).

Option Analysis

• (1) Ustilago nuda: Causes loose smut of barley (and wheat); spores are exposed and powdery, not covered by a membrane, emerging early from infected florets—unlike covered smut’s intact spore sacs.

• (2) Ustilago kolleri (syn. Ustilago segetum or U. avenae): Responsible for covered smut of oats, not barley; infects oat seeds similarly but host-specific, producing covered sori in oat panicles.

• (3) Ustilago scitamineae: Pathogen of sugarcane smut, forming whip-like sori on sugarcane; unrelated to barley or grains, targeting monocots like Saccharum.

• (4) Ustilago hordei: Correct; causes covered kernel smut in barley (Hordeum vulgare), seed-borne, systemic infection leading to dark brown teliospores enclosed in gray-white peridium on grains at maturity.

Covered smuts disease in Barley Ustilago hordei is a seed-borne fungal infection transforming barley kernels into covered spore masses, impacting yield worldwide. Ustilago hordei, a Basidiomycete smut, penetrates seedlings from contaminated seeds, growing asymptomatically until spike formation.

Disease Characteristics

Infection starts at sowing; mycelium colonizes meristems, producing sori at kernel sites by anthesis. Covered smuts feature a tough peridium enclosing teliospores, rupturing post-harvest to contaminate seed—unlike loose smuts. Favored by cool, moist soils; yield loss up to 30% in untreated fields.

Pathogen Comparison

Management Strategies

Use certified disease-free seeds, hot water treatment (52°C/10 min), or carboxin-based fungicides. Resistant varieties like those with ‘Dw2’ gene reduce incidence. Early rogueing limits spread in fields. Crucial for GATE/NEET Life Sciences and crop protection studies.