Wheat streak mosaic virus is the most prevalent disease in the southwestern wheat producing region of the U.S., according to a Texas AgriLife Research scientist.

Dr. Charlie Rush, AgriLife Research plant pathologist in Amarillo, is assembling several teams of scientists to work on the disease from every aspect: vector to diagnosis and mapping to control.

"There are other diseases of concern, but wheat streak mosaic is always found somewhere in this wheat growing region, and every couple of years, we have an epidemic of it," Rush said.

Several issues cause the disease to be more problematic, he said. It is hard to distinguish the disease from drought or nutrient deficiencies because the symptoms often look similar in all three. Also, the vector is so tiny it can't be seen in the field, so the disease is already present before it can be detected. And there are no chemical controls for either the insect or disease.

The disease doesn't just affect grain and forage yields, but has a negative effect on the ability of the wheat plant to use irrigation water, Rush said. Therefore, irrigation applied to diseased wheat wastes time, energy and groundwater.

Through a Texas Cropping Systems grant, work was started about a year ago to look at the factors that affect disease incidence and severity, primarily at the vector, which is the wheat curl mite, Rush said.