Wet weather encouraging yield-hurting wheat diseases
Weeks of wet weather have increased the chances that wheat disease will affect yield, plant pathologists with the University of Arkansas Division of Agriculture said on May 18.
"We were looking at a light to moderate disease year until about two weeks ago," said Scott Monfort assistant professor-extension plant pathologist based at the Rice Research and Extension Center at Stuttgart. "The extensive rain events have pushed diseases like Septoria leaf blotch, powdery mildew, and Fusarium head blight, also known as wheat scab, typically minor problems, to be major.
Monfort said the Division of Agriculture is not encouraging growers to apply fungicide for these problems beyond the flowering stage, due to label restrictions.
Gene Milus, Division of Agriculture plant pathologist based at Fayetteville, said there was little growers could do to prevent head blight.
"The only way to have prevented head blight would have been to not plant any wheat," he said. "All current wheat varieties are more or less susceptible, and the Fusarium fungi that cause head blight are ubiquitous.
"The absence of long periods of rainy weather after heading stage is the only thing that limits head blight during most years," he said.
Division personnel will be surveying grower fields in the coming week to determine the incidence of Fusarium head blight and how much of the crop has been affected across the state. What they've found so far is that fields in the Arkansas River Valley and the Delta were showing scab from less than 1 percent to 20 percent of the wheat heads as of two weeks ago.
There is some good news--forecasters are predicting several days of dry weather, which may help forestall the spread of these diseases.
The Cooperative Extension Service is part of the University of Arkansas Division of Agriculture.