Betapartitivirus rhiso

Pathogen and disease type. Betapartitivirus rhiso is a member of the genus Betapartitivirus within the Partitiviridae family. It is a double-stranded RNA virus categorized as a mycovirus, meaning it infects fungi, particularly Rhizoctonia solani, rather than directly invading plant host tissues.

Affected crops. This virus primarily infects Rhizoctonia solani, a soil-borne fungal pathogen responsible for significant economic losses in various crops such as potatoes, cereals, and vegetables. By residing within the fungus, the virus can modulate the severity of the diseases caused by R. solani.

Symptoms and signs. The presence of the virus in fungal cells often leads to hypovirulence, reducing the pathogen's ability to kill the host plant. However, infected crops still exhibit signs of rhizoctonia disease, such as necrotic lesions on stems, pre-emergence damping-off, and reduced plant vigor, often exacerbated by environmental stress.

Development and transmission. Transmission occurs primarily through hyphal anastomosis between infected and healthy fungal mycelia. Since the virus persists within the fungal structures, it remains viable in the soil for long periods, spreading alongside the fungus as it colonizes new root systems of susceptible plants.

Harmfulness and preventive measures. The overall impact depends on the viral-fungal interaction. While some strains might reduce fungal virulence, the host plants remain at risk. Preventive measures include crop rotation to break the disease cycle, maintaining soil health to discourage fungal proliferation, and using registered chemical fungicides targeted against Rhizoctonia species.