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Posted 15 April 2008. PMN Crop News.

Triticum Mosaic Virus Adds New Wrinkle to Wheat Disease Picture

Kansas State University.

Manhattan, Kansas (March 25, 2008)--First found by Kansas State University researchers in 2006, a newly discovered virus affecting wheat was officially recognized and named Triticum Mosaic Virus in 2007.


The discovery was made by plant pathologist Dallas Siefers and wheat breeder, Joe Martin, both of whom are based at the K-State Agricultural Research Center in Hays.

Triticum Mosaic Virus is now considered one of three viruses affecting wheat in approximately the same manner - the other two being Wheat Streak Mosaic Virus and High Plains Virus, said Erick DeWolf, K-State Research and Extension plant pathologist. All of these virus diseases are vectored, with varying degrees of efficiency, by the wheat curl mite, DeWolf said. In addition, the disease symptoms of all three diseases are virtually identical, he added.

Although some initial observations have been made, many aspects of Triticum Mosaic Virus remain largely unknown at this point, including varietal reaction, distribution within Kansas, and yield loss potential.

"Although there has been no conclusive varietal screening for Triticum Mosaic Virus alone yet, it is known that RonL is susceptible," DeWolf said. Thatīs important because RonL is the first variety to have true genetic resistance to Wheat Streak Mosaic, at least under cool temperature conditions. If RonL shows Wheat Streak Mosaic symptoms, and temperatures have been cool, then Triticum Mosaic Virus should be suspected. Otherwise, the effect of Triticum Mosaic Virus alone on varieties is not known.

To date, Triticum Mosaic Virus has been confirmed in Cheyenne, Ellis, Ford, Ness, Osborne, Pawnee, and Thomas counties in Kansas, the plant pathologist said. These are the only locations where samples have been taken for testing, and all have been positive so far.

At this point, there is no reason for producers to be unduly alarmed by the detection of this new virus disease on wheat, DeWolf said.

"Triticum Mosaic Virus may have been present at low levels for many years in the High Plains, and was only now detected when disease symptoms appeared on RonL, which is known to be resistant to Wheat Streak Mosaic under most conditions," he said. "It is also possible that Triticum Mosaic Virus is new to the High Plains, but there is no way to know for sure."

Because Triticum Mosaic Virus is vectored in the same manner as Wheat Streak Mosaic and High Plains Virus, producers should take the same preventive measures against the disease: control volunteer wheat and plant after the Hessian fly-free date, DeWolf said. There is no practical way for producers to distinguish Triticum Mosaic Virus symptoms from the symptoms of Wheat Streak Mosaic - unless the symptoms occur on RonL.

Erick DeWolf