Beet necrotic yellow vein virus

Beet necrotic yellow vein virus (BNYVV) is a significant plant pathogenic virus belonging to the genus Benyvirus. It is recognized as the causal agent of rhizomania, a devastating disease of sugar beets worldwide. The virus consists of rod-shaped particles containing a multipartite single-stranded RNA genome, which facilitates its biological adaptability.

The primary symptom of the disease is the proliferation of thin, hair-like lateral roots, often described as a "beard" or "root madness." Infected plants show stunted growth, yellowing (chlorosis) of the leaves, and necrotic browning of the vascular tissues. These symptoms lead to reduced root weight and a significant decrease in sucrose content, causing severe economic losses.

The virus is transmitted by the soil-borne obligate parasite Polymyxa betae, a plasmodiophorid protist. The virus particles are harbored within the resting spores of the vector. Because these spores can persist in the soil for over 15 years, the virus remains an enduring threat to beet production fields once established.

Favorable conditions for infection include high soil moisture levels and moderate temperatures, which promote the motility of Polymyxa betae zoospores. The pathogen is spread across regions primarily through the movement of contaminated soil attached to farm machinery, tillage equipment, and irrigation water, or through infected beet debris.

Current management strategies rely heavily on the cultivation of resistant or tolerant sugar beet varieties, which is the most effective approach. Additional control methods include:

• Strict field hygiene and cleaning machinery to prevent soil transport.
• Improving soil structure and drainage to reduce vector activity.
• Avoiding the planting of sugar beets in known heavily infested soils.
• Implementing long-term crop rotations to manage vector populations.