PhysOrg.com by Kay Ledbetter:
Wheat streak mosaic virus is the most prevalent disease in the southwestern wheat producing region of the U.S. Dr. Charlie Rush and Jacob Price, AgriLife Research plant pathologists in Amarillo began a study with varieties of wheat with bred-in resistance to wheat streak mosaic virus and an influence of different temperatures.
The disease incidence depends on vectors: wheat curl mites, which have the potential to build high populations very quickly. When populations explode, wheat streak can spread to epidemic proportions in a short time, causing devastating losses throughout the wheat growing region. The temperatures affect this process: “If you have a lower number of mites, and a lower number of those are carrying the wheat streak virus, it will reduce the incidence of disease and reduce the potential for development of an epidemic,” Rush said.
Study shows that temperatures above 24 deg C may change disease resistance to the virus bred into them. While several varieties of wheat have resistance, there has been a problem with that genetic resistance breaking down in temperatures above 75 degrees F.