Disease outbreaks found in winter wheat plots
SHEBOYGAN – Based on recent visits by state level plant pathologists to the state's four winter wheat trial plots, Sheboygan County Extension Service crops and soils agent Mike Ballweg has issued an advisory to growers and crop consultants to check for one or more plant diseases.
The observations by Extension Service field crops pathologist Damon Smith and graduate student research assistant Brian Mueller found significant differences between winter wheat varieties in their susceptibility to stripe rust, Ballweg reported.
On the winter wheat varieties known to be susceptible to the stripe rust, the disease outbreak had risen to “epidemic levels” by the last week of May in the winter wheat trial plots, Ballweg noted. Those varieties had stripe rust on the leaf immediately below the flag with some having 20 percent or more severity on the flag leaves themselves, he pointed out.
At the same time, there have also been reports from across the state that some fields of winter wheat are virtually free of plant diseases, Ballweg added. He suggested that this shows the value of choosing varieties with excellent resistance to stripe rust.
Growers whose wheat has not yet reached the flowering stage could apply a fungicide, especially on those varieties with minimal resistance to stripe rust, Ballweg and the pathologists indicate. In his analysis circulated on May 28, Smith observed that fusarium head blight is a potential threat after the flowering stage and that in some cases it might be possible to apply a fungicide to address both of the diseases.
Even without the likely yield losses being caused by plant diseases, Wisconsin's winter wheat crop for this year was forecast to drop by 29 percent compared to 2016 due to a combination of reduced acres and yields per acre. More acres are being lost as some growers have begun to harvest uneven and disease plagued stands as forage.
The initial forecast for a winter wheat production of 14.1 million bushels for this year was based on crop conditions as of May 1. An update based on June 1 conditions will be issued on June 9.