Genus Luteovirus
- Symptoms: The symptoms of barley yellow dwarf (BYDV) vary with the affected crop cultivar, the age of the plant at the time of infection, the strain of the virus, and environmental conditions. Symptoms often are masked by or confused with other problems. Affected plants show a yellowing (picture at right) or reddening (on oats and some wheats) of leaves, stunting, an upright posture of thickened stiff leaves (picture at left), reduced root growth, delayed (or no) heading, and a reduction in yield. The spikes of affected plants tend to remain erect and become black and discolored during ripening due to colonization by saprophytic fungi.
- Development: Temperatures of approximately 20°C are favorable for disease development and symptoms appear approximately 14 days after infection.
- Vectors / Hosts / Distribution: The term barley yellow dwarf virus (BYDV) includes several related viruses that are all aphid transmitted. Over 20 species of aphids may act as vectors. BYDV is probably the most widely distributed viral disease of cereals in the world. It attacks not only wheat, but also barley, triticale, oats, and many other grass species.
- Importance: Infections occurring early in the crop cycle can result in yield losses of more than 20%, and much larger losses have been recorded.
