Diseases of Wheat - Viral

Barley Yellow Dwarf

What to look for?
Most wheat cultivars are resistant to this aphid-borne virus disease. Some spring wheat cultivars and winter wheat selections are quite susceptible, as shown by stunting and leaf yellowing. Barley yellow dwarf virus overwinters in wild grasses. Grain aphids transmit this virus once infested in a persistent manner. At the end of the growing season in mid- to late-August, most Alberta wheat plants will test positive for this virus though no symptoms may be visible.

Photo: Haber

Picture description
Yellow colour of heavily infected wheat.

Photo: Haber

Picture description
Yellow leaves on infected plant.

Management strategy
No feasible controls are recommended for this disease in wheat.

A more complete description of Barley yellow dwarf virus.

Wheat Streak Mosaic and Spot Mosaic Virus

This virus disease can cause crop failure in winter wheat and severe injury in spring wheats. Actually two viruses cause this disease, spot mosaic and streak mosaic, both of which are spread by the same mite vector. Spot Mosaic only occurs in Southern Alberta.

What to look for?.

Photo: Haber

Picture description
Distinct yellow streaks on virus infected leaves.

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Management strategy
Wet summers that allow virus infected volunteer wheat to grow alongside new fall-seeded fields of winter wheat are the cause of major yield losses in the winter wheat. Spot mosaic is much less common than streak mosaic. See Wheat Streak Mosaic in Alberta and Its Control, FS112/632E for full description and control.

A more complete description of Wheat streak mosaic virus.

Photographs and information assembled and prepared for ARD by Dr. Ieaun R. Evans Agri-Trend Agrology Ltd.

Diseases of Wheat - Viral

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