Wheat streak mosaic virus confirmed in Oklahoma wheat

Monday, April 10, 2017

Oklahoma State University’s Plant Disease and Insect Diagnostic Laboratory has confirmed the presence of wheat streak mosaic virus in Oklahoma.

“Unfortunately, there is not much a wheat producer can do at this stage,” said Heath Sanders, OSU Cooperative Extension area agronomy specialist. “It’s why we recommend producers employ the proper cultural controls around planting time in the fall.”

The virus is transmitted via the wheat curl mite, a small, cigar-shaped pest that can do big damage to a crop. Plant mortality potentially can be extensive, robbing a producer of his or her investments in time, effort, seed and harvest loss.

“Wheat streak mosaic is difficult to control because there are no wheat varieties that are highly resistant to the virus or to the wheat curl mites,” Sanders said.

Producers therefore must rely on cultural controls, including controlling volunteer wheat at least two weeks prior to planting in the fall and delaying planting of the seedling wheat.

“Wheat curl mites have a life span of about two weeks, so controlling volunteer wheat in and surrounding a field for at least two weeks will greatly reduce the number of mites that can infect the seedling wheat in the fall,” Sanders said.

Planting wheat late reduces the length of time mites have to infest wheat and transmit wheat streak mosaic virus in the fall, which results in the most severe yield reductions.

Varying degrees of yellowing and tissue death are associated with wheat streak mosaic. Leaves of plants infected with wheat streak mosaic virus generally appear light to medium green with yellow streaks, which usually are longer than the streaks on leaves of plants infected with wheat spindle streak mosaic virus.