Friday, April 17, 2015

Barley Yellow Dwarf Virus and Stripe Rust Updates


By Juliet Marshall, University of Idaho Cereal Cropping Systems Agronomist and Pathologist, Aberdeen Research & Extension Center.

Idaho Barley yellow dwarf symptoms are now appearing in additional areas in eastern Idaho (Hamer, Idaho Falls, Shelly, Blackfoot, Pocatello Valley, Soda Springs, Preston, Northern Utah) in winter wheat and winter barley (although there is less winter barley in these areas). As fields in southern and western Idaho start to develop flag leaves and initiate heading, you may see a reappearance of symptoms in the flag leaves. (See the picture of Stephens just prior to heading in the CIS 1210 at: http://www.cals.uidaho.edu/edcomm/pdf/CIS/CIS1210.pdf ).

The symptoms do not seem to be as severe or extensive in eastern Idaho, but we are keeping an eye on the situation, especially due to the complications of cold weather and snow causing tips burn and freeze damage. Also being seen is leaf purpling that may be phosphorus deficiency.

This virus is finicky to test, and it is hard to detect the virus in ELISA tests that depend on virus concentrations in the plant tissue. 

Without the presence of high populations of aphids, we don’t expect the virus to be a problem in our spring wheat and barley. The virus requires aphids for transmission.

Barley Yellow Dwarf Sample Testing
We are no longer processing samples, due to the expense and time associated with testing. 
But if you wish to have samples tested, please contact one of the following people: 

Harry Kreeft at Western Labs in Parma, ID

Liz Vavricka at the ISDA (will test a limited number of samples from western Idaho)
Plant Industry Laboratory
P.O. Box 790
Boise, ID 83701
Office: (208) 332-8640
Fax: (208) 332-8645

STRIPE RUST 

Please also be aware that the potential for stripe rust to show up early and be more severe than last year is high! Keep an eye out for stripe rust in susceptible varieties, especially Brundage soft white winter wheat. Reports from Washington and Oregon indicate high infection levels in susceptible varieties. With cool / cold temperatures and very high winds, we could be in for damaging levels of this disease.

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