Bean Yellow Mosaic Virus (BYMV)

CAUSED BY

• Caused by Bean Yellow Mosaic Virus (BYMV) which is a common mosaic disease of faba bean caused by potyvirus group.
• Two variants of the virus have been identified: mild (leaf mosaic with no necrosis) and severe (leaf mosaic with necrosis).
• Virus is spread from overwintering hosts such as clovers and vetch to faba bean by aphids
• While infections seldom cause plant death, the impact of yield will depend upon the time of infection, with earlier infections having greater impact.

SYMPTOMS

• Symptoms start to show 7 – 10 days after the plant has been infected.
• The youngest leaves have milder green mosaic mottling and veins appear to be branded or yellow; rolling and narrowing of leaves occurs and plants suffer from stunting.

PREVENTION AND CONTROL

• Use certified seed.
• Fungicides are ineffective in managing viral diseases.

IMPACT

• This virus is not currently producing economic losses in Alberta.

RESOURCE

• Alberta Faba Bean Producers Manual
• North Dakota Agriculture Experiment Section, Pea Seed-Borne Mosaic Virus (PSbMV) in Field Pea and Lentils