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Wheat Spindle Streak Mosaic Virus

© Purdue University, Plant and Pest Diagnostic Laboratory

Pathogen(s) causing disease:

Wheat yellow mosaic virus (WYMV)


Yellow-green mottling, dashes, and streaks on lower leaves. Reddish streaking and necrosis at leaf tips sometimes occurs. Fewer tillers, seeds, and heads. Mild stunting.


The virus particles are carried on or in the fungal zoospores (swimming spores). The fungus invades root hairs of the young wheat in the fall during periods of high soil moisture. Apparently spring infections are possible but inconsequential to the wheat.

The fungus forms dark clusters of resting spores in the wheat roots which are released to the soil when the roots decay. Since the fungus survives in the soil as resting spores, the disease is always associated with infested soil. Soils may remain infective for at least 8 years. Neither WSSMV nor WSBMV are insect-borne or seed-borne. Wheat is the only known host of WSSMV.


Tolerant varieties.


Kansas State University
Purdue University

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