A 2015 research project revealed the most prevalent viruses on wheat in Oklahoma, along with detecting two new viruses in the state. These findings will help wheat growers better scout for wheat viruses, identify viruses quickly and understand how to treat specific viruses, leading to more efficient and economical virus management in wheat.
Wheat is the leading crop in Oklahoma, bringing an income of more than 600 million dollars to the state. Plant viruses are one of the major causes of yield losses in wheat and other crops, since lack of knowledge about symptoms can lead to rapid spread. Often virus symptoms look like symptoms of other issues, so growers do not treat before damage is done.
Using funding from a 2015 Southern IPM Center IPM Enhancement Grant, University of Tulsa Plant Virologist/Plant Pathologist Dr. Akhtar Ali led a project to catalog viruses detected on Oklahoma wheat. The goal of the project was to identify the viruses present in wheat crops of Oklahoma and determine how prevalent they were on wheat in the state.
Surveys in 33 counties for a total of 15 possible wheat viruses revealed five major viruses in the state. Barley mild mosaic virus (BaMMV) was the most prevalent, followed by Wheat streak mosaic virus (WSMV), Barley yellow dwarf virus-PAV (BYDV-PAV), Barley yellow dwarf virus-RPV (BYDV-RPV) and High plains virus (HPV). Five other viruses were detected, but their incidence was below 2 percent.
Dr. Ali, also surveyed weeds nearby wheat fields and discovered that several weeds served as reservoirs for viruses, including Johnson grass, cheat grass and ryegrass. Ryegrass samples tested positive for four different viruses. Researchers discovered BaMMV in cheat grass and Johnson grass mosaic virus (JGMV) in Johnson grass.
In fact, JGMV was one of two viruses discovered during the project that had not been reported before. Maize chlorotic motile virus (MCMV) was the other. Although both viruses were not detected at levels above 2 percent, their discovery provides new information to growers as they scout their fields. Dr. Akhtar Ali and Dulanjani Wijayasekara reported the discovery of JGMV in a peer-reviewed article in Plant Disease Journal.
The discovery of these viruses, along with the dissemination of the information to Extension educators and growers, will help wheat growers more quickly identify wheat viruses and treat them before they cause economic damage.
Reference: D. Wijayasekara and A. Ali (2017). First report of Maize Dwarf Mosaic Virus in Johnsongrass in Oklahoma. Plant Disease. http://dx.doi.org/10.1094/PDIS-12-16-1767-PDN