Barley Yellow Dwarf (BYD) is caused by the viral pathogen Barley Yellow Dwarf Virus (BYDV) complex.
The BYDV complex consists of five closely related viruses in the Luteoviridae family.
The virus is spread by aphid vectors.

Identification

Symptoms are often patchy due to aphid movement.
Symptoms are most notable on the flag leaf and can be yellow, red, and/or purple (Fig 1).
Infected plants may be stunted and have decreased internode lengths.
Enzyme-Linked Immunosorbent Assay (ELISA) testing by laboratory or extensions services maybe necessary for accurate strain identification.

Fig 1: Yellow to purple flag leaf discoloration symptoms caused by Barley Yellow Dwarf Virus

Fig 2: Bird cherry-oat aphids

Management

Bird Cherry Oat Aphids are associated with more yield loss than other aphid vectors (Fig 2) and fall infection is more damaging than infection of mature plants in the spring.
Insecticide use is not usually economical due to sporadic aphid movement.
Delaying planting until aphid populations decline can reduce the risk of BYD.
Control grass weeds and volunteer
cereals that are food sources for aphids.
Genetic resistance is available in oats but
limited in wheat and barley.

References

Crop Protection Network (2022, January 28). Barley

Yellow Dwarf of Wheat. Retrieved from:

https://cropprotectionnetwork.org/encyclopedia/barley-yellow-dwarf-of-wheat

D'Arcy, C. J., and L. L. Domier. “Barley Yellow Dwarf.”

Barley Yellow Dwarf, American Phytopathological Society, 2005,

https://www.apsnet.org/edcenter/disandpath/viral/pdlessons/Pages/BarleyYelDwarf.aspx

Frank Peairs, Colorado State University, Bugwood.org

Authors: Joseph Cinderella and Dr. Alyssa Koehler

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