Wheat streak mosaic virus (WSMV) has hit the wheat crop in western Kansas. The virus is spread by the wheat curl mite and causes stunted growth and streaks of yellowed, non-uniform discoloration, and has been known to cause 100 percent crop mortality.
The wheat crop in the counties of Finney, Greeley, Wichita, Lane, Hamilton and Kearny are affected by WSMV, as well as triticum mosaic and high plains mosaic virus, according to the Kansas State University Research and Extension Agronomy. The affected areas are at risk for 70-100 percent crop loss. Areas of central Kansas are experiencing high and moderate infection levels, according to Kansas Wheat.
The amount of crop losses will depend on the variety, weather and percentage of plants infected.
“Infections that occur in the fall are the most damaging, with yield losses of 50 percent or more. Spring infections may cause losses closer to 20 percent,” Kansas Wheat said.
While there is no chemical treatment for WSMV, there are management techniques, including controlling volunteer wheat.
“Volunteer wheat provides a ‘green bridge’ through the summer between successive wheat crops, and that green bridge is the perfect home for wheat curl mites, the only known vector of WSMV. The volunteer wheat must be thoroughly destroyed for no fewer than two weeks in order to eliminate the wheat curl mites. Kansas winds are the preferred mode of transportation for wheat curl mites, so volunteer must be killed within one-quarter to one-half mile of a newly planted field,” according to Kansas Wheat, which said avoiding early planting can also control the virus.