Wheat Streak Mosaic Virus
Apr 02, 2020
In light of current events, I thought it would be a good time to take a look at viral diseases affecting crops. There are some parallels in the issues of dealing with viruses in plants and humans. I’ll do my best to draw comparisons between COVID-19 and plant disease.
One of the more significant viral diseases in plants is the Wheat Streak Mosaic Virus. Unlike COVID-19 which spreads by droplets, WSMV is spread by wheat curl mites. These mites can pick up the virus from basically any kind of grass and be blown by wind into a susceptible wheat field. This is particularly difficult for winter wheat since these mites can survive very cold temperatures and infect winter wheat as it begins to grow in the fall. The infection remains as the crop resumes growth in spring. The mites are highly difficult to control. Insecticides and cold temperatures are not effective. Really the only effective means of controlling these mites is destruction of potential hosts. The key here is spraying volunteer spring wheat before planting winter wheat in that type of a crop rotation.
Wheat Streak Mosaic will yellow plants significantly, causing lack of photosynthesis and damaging potential yield. Once an infection occurs, there is no treatment but rotating to a non-susceptible host and waiting. Corn is also a host for both the virus and the mites as well as brome, green and yellow foxtail, and many of our native species though the virus damages none as much as wheat. While wheat, especially winter wheat, are not major crops in our area at this time, this disease can wreak havoc in the lower Midwest and the winds have the potential to blow it up here on the backs of those troublesome mites.