Fungal Vectored Virus Diseases of Sugar Beet

Rhizomania

Beet necrotic yellow vein virus, vectored by Polymyxa betae, causes rhizomania, the most economically important disease of sugar beet worldwide. We recently reported that strength of genetic resistance was positively correlated to mutation frequency in BNYVV RNA 3 and that this could lead to rapid emergence of new resistance breaking (RB) strains. This hypothesis was verified this season with emergence of new RB strains of BNYVV that overcame Rz2 genetic resistance in sugar beet. Furthermore, the mutation in BNYVV associated with overcoming Rz1 resistance is not present in Rz2 RB strains of BNYVV. Priority research areas include:

• Beet necrotic yellow vein virus population genetics
• Evolution of resistance breaking strains of BNYVV
• Virus/vector interactions
• Benyvirus strain/species competitionspecies competition