Barley Yellow DwarfCausal Agent: Barley yellow dwarf virus
Hosts: Wheat, barley, oats, etc. Barley yellow dwarf virus attacks oats and wheat is transmitted by many species of aphids. In Oklahoma, the two most common aphids associated with transmission are the bird-cherry oat aphid (Rhopalosiphum padi) and the greenbug (Schizaphis graminum).
Symptoms: In Oklahoma in mid-March through early-April, wheat, barley or oat plants infected with barley yellow dwarf virus generally have varying degrees of yellow, red, and/or purple associated with the foliage. Generally infected plants appear in circular patches corresponding to aphid infestations that occurred sometime through the fall. Usually the yellow, red and/or purple color is expressed more toward the leaf tips than toward the base of the leaves. As the season progresses and temperatures rise, the red or purple colors are replaced with chlorosis (yellowing) and necrosis (tissue death). Barley yellow dwarf-infected plants, especially if infected in the fall, will be significantly shorter than non-infected plants.
Control: Some wheat varieties such as 2137 and Custer have some tolerance to barley yellow dwarf, but no variety is highly resistant. Controlling the aphid vectors with chemicals will help to limit incidence and spread of barley yellow dwarf, but frequently aphids transmit the virus before reaching levels believed sufficiently high to merit application of an insecticide. Planting late also helps reduce incidence and severity of barley yellow dwarf because of the reduce time in the fall for aphid infestations and transmission of the virus. Please contact your local county extension office for current information.
Additional information can be found in the most current OSU report of barley yellow dwarf control on wheat.
For more information you may contact Dr. Robert Hunger, e-mail address: firstname.lastname@example.org
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