Wheat soil-borne mosaic

Wheat soil-borne mosaic, caused by the Wheat soil-borne mosaic virus (WSBMV) of the Furovirus genus, is a significant viral disease affecting winter cereals. This pathogen is unique due to its ability to persist in soil for decades, making it a persistent threat to cereal production globally.

The disease primarily impacts winter wheat, although it can infect barley and rye. The virus is obligately transmitted by the soil-borne plasmodiophorid fungus Polymyxa graminis, which infects the roots of wheat seedlings, delivering the viral particles directly into the plant cells.

Early symptoms are most visible in early spring, appearing as chlorotic stripes, mosaics, and mottling on the foliage. Infected plants often exhibit stunting, excessive but weak tillering, and an overall rosette appearance. In severe cases, the foliage may turn necrotic, leading to substantial crop thinning.

The development of the disease is highly dependent on environmental factors, specifically soil moisture and temperature. Cool, wet conditions in the autumn facilitate the infection of wheat roots by Polymyxa graminis, while a cool spring promotes the systemic spread of the virus throughout the plant.

Management of this viral infection is challenging as there are no direct chemical treatments to cure infected plants. Control strategies rely heavily on preventive measures:

• Planting resistant or tolerant wheat cultivars specifically bred for WSBMV resistance.
• Implementing long-term crop rotation to reduce the inoculum levels of the fungal vector in the soil.
• Avoiding planting in fields with known history of soil-borne viral infestations.
• Improving soil drainage to minimize the conditions favorable for the fungal vector.