Small grains pest alert issued in Idaho

BYD virus has been reported in winter barley in south-central Idaho. Yield losses increase with earlier infections, especially if they occurred the previous fall, which is likely in this case, and can approach 100 percent in severely affected fields.

The Pacific Northwest Pest Alert Network has issued a pest alert for barley yellow dwarf virus in small grains in south-central Idaho.

BYD in winter barley in the Filer area was reported by Steve Hines, University of Idaho Extension educator for Jerome County.

The network recommends producers scout for the disease in winter wheat and barley fields. Yield losses increase with earlier infections, especially if the infection occurred in the previous fall, which is likely to be the case, the alert noted.

Symptoms include yellowing of leaves, stunting of plants above and below ground and irregular heading with small heads in affected plants. Often, the most severe symptoms will occur along field edges and the edges created along the tracks of pivot tires, the alert stated.

There may also be a yellowing to a characteristic reddening of leaves of infected weedy grasses in nearby ditch banks, which also host the virus and the aphids that help spread it. Additional symptoms may also include notching of the leaf margins, twisting, leaf tip scorch, and abnormal development of emerging leaves.

The alert also noted:

• Fall infection occurs as large populations of aphids migrate from other crops to newly emerged wheat or barley.

• At this point, reducing crop stress will reduce the effect of the virus on the plant, but yield losses will occur both through reduced grain production as well as reduced test weight.

• The most effective control is through the use of resistant varieties, but insecticidal seed treatments may reduce the initial spread in fall wheat and barley.

Online

To view the full alert, and to download any attached files:

www.pnwpestalert.net



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