How do you know when an Extension program is a success? Perhaps it’s when the practices it promotes become so widely adopted that they become the norm.
Ames Herbert, Extension specialist at the Tidewater Agricultural Research and Extension Center, along with Extension agents David Moore, Keith Balderson, and Paul Davis, recently became aware of the impact of their educational programs on barley yellow dwarf virus when they studied how Virginia growers are combating the disease.
“We looked around and realized that over the past 10 years — by analyzing the research, doing field demonstrations, preparing educational materials, and collecting and sharing data — we have effected a major change in the way growers approach this disease,” Herbert says. “What we’ve taught has become the normal practice — it’s a great feeling.”
Barley yellow dwarf virus attacks small grains, causing stunted growth and smaller seed heads, which can contribute to yield losses of up to 20 to 30 percent. In eastern Virginia, wheat and barley are planted in the fall, giving the plants a good start before the first frost and allowing for vigorous growth when temperatures begin to warm up the following spring. The virus becomes noticeable on the plants during the active time of spring growth; in the past, producers used planting-time foliar sprays to try to control the disease. This practice was only marginally effective.
Extension specialists studied the research about barley yellow dwarf virus and learned that although disease symptoms appear on plants during the spring, the virus is actually transmitted through aphids feeding on the fall-planted seedlings.
The research showed that controlling the aphid population on the plants in the fall gets good results. Extension specialists and agents worked with growers to determine which fields were most at risk for developing the virus and to control it in the fall — either with seed treatments or foliar insecticides applied between the three-leaf stage and early tillering.
Over time, fall evaluation and treatment has become the common practice for controlling barley yellow dwarf virus in Virginia’s wheat and barley crops. When the Extension faculty surveyed growers, they found that 96 percent of them understood the connection between the virus and the presence of aphids in their fields in the fall. Well more than half of the growers reported that their wheat and barley yields improved after adopting the fall control methods — by as much as from 8 to 30 bushels per acre — and representing anywhere from $26 to $52 per acre in profits.