Bad news, good news, more bad news and maybe some even better news may be coming out of wheat research plots at the USDA-ARS/Texas AgriLife Research station in Bushland, Texas.

Wheat streak mosaic virus, says AgriLife research pathologist Charlie Rush, can be a devastating disease for High Plains wheat producers.

Good news for growers—two varieties, Mace and Ron L, have shown resistance to the virus. But, bad news, that resistance breaks down with temperatures above 75 degrees. Since farmers in the region plant a lot of wheat in August and early September, young plants are exposed to temperatures much higher than 75 degrees and consequently to wheat curl mites, which transmit the wheat streak mosaic virus.

“Early planted wheat for grazing has a higher exposure to plant pathogens such as wheat streak mosaic virus,” Rush said.

“We wanted to see if resistant varieties would recover once temperatures cooled down in the fall,” Rush said during a recent “Wheat and Water Issues” field day at the station.

They found more bad news. “Mace and Ron L did not recover,” Rush said.

But they did discover something else that could help farmers manage the disease.

“We planted Karl 92, TAM 111 and TAM 112 as checks,” Rush said. “We found low levels of the curl mite on TAM 112. It is extremely resistant to curl mites. Populations do not build up.”

He says the wheat is still susceptible to the virus and when transmitted by the mite will be infected with the disease.

“But reduced numbers of mites means less disease pressure,” he said. “That’s really good news. If wheat breeders can identify genetic resistance to mites, we have less to worry about genetic resistance to diseases. In 2013, we will look at planting multiple lines with various resistance traits, for instance, different varieties with some resistant to diseases and some resistant to insects.”

He said farmers could plant a mixture of varieties to reduce opportunities for insects, such as curl mites, to build to damaging populations and to offer protection against other diseases, such as leaf rust. “Farmers could have seed dealers prepare the mix they want.”

Mixed varieties could also help with problems such as lodging. Rush said wheat producers would need to match maturity dates and other characteristics to meet management goals.