Crops and Horticulture Focus

With wheat harvest completed across the Midway District, producers should already be thinking about controlling volunteer wheat. In years past many producers have had severe problems with wheat streak mosaic virus and in most cases, it can be traced back to lack of control of volunteer wheat which creates a green bridge, allowing wheat streak mosaic and wheat curl mites to survive locally.

This year, the wheat crop faced several challenges that could increase the amount of seed left behind after the wheat harvest, which will also increase the amount of volunteer wheat. Some of the problems we saw in the Midway District include hail, fusarium head blight, and waterlogged conditions.

Producers often wait several weeks after harvest to allow as much volunteer wheat to emerge before making their first herbicide application, or tillage to control volunteer wheat. But more than likely another spray application or tillage will be needed to control later emerging volunteer wheat later in the summer to eliminate the green bridge to wheat by making sure all volunteer wheat is dead within a half mile of wheat being planted in the fall.

Volunteer wheat is not the only host of the wheat curl mite, research studies have evaluated the suitability of wild grasses as a possible host for the wheat curl mite and wheat streak mosaic virus. Barnyardgrass is among the more suitable host for both virus and mites, and also some of the various foxtails although a rather poor host, could be an important disease reservoir simply because of their abundance, these grasses also could play an important role in allowing the mites and virus to survive during the summer months, so it is important to control them also.

Planting wheat with genetic resistance to wheat streak mosaic can reduce the risk of severe disease problems. Currently, there are only three varieties adapted to Kansas: Clara CL (white) Joe (white), and Oakley CL (red). These varieties have the same resistance source (WSM2) it does have some limitations.

For example, this resistance source does not cover triticum mosaic virus or high plains virus, it is also temperature sensitive and is less effective at high temperatures. In addition, there are some varieties with resistance to the wheat curl mite, but those varieties are still susceptible to the wheat streak mosaic virus, but they generally slow the development of the mite populations in the fall.

As a general rule of thumb, volunteer wheat should be controlled and completely dead two weeks before planting the new wheat crop this fall to ensure wheat streak mosaic virus won’t spread to the newly planted wheat.

Information sourced from Extension Agronomy eUpdate Wheat streak mosaic the importance of early control of volunteer wheat.

For more information contact Craig Dinkel, Midway District Extension Crops and Horticulture Agent. Dinkel can be reached by email at cadinkel@ksu.edu,or by phone at (785) 472-4442 or

(785) 483-3157.