K-State’s DeWolf says growers should be on the lookout for fungal disease
MANHATTAN – A Kansas State University wheat disease specialist says the state’s growers should be on the lookout for Fusarium head blight, also known as head scab, as they prepare to bring in the 2019 crop.
Erick DeWolf said the incidence of the disease seems to be higher this year than it has been over past years, showing up in parts of central Kansas in addition to eastern Kansas, where it has previously been more common.
“We’re still trying to get a full picture of the disease levels this year, but as we’ve been out doing plot tours (the past five weeks) in many areas of central Kansas and eastern Kansas, it looks like weather conditions were ideal for the development of Fusarium head blight back in May,” DeWolf said.
“We may see problems with Fusarium head blight this year in many areas of eastern and central Kansas. However, the full extent of the damage is unknown at this time.”
Fusarium head blight is a fungal disease that affects the developing grain and can produce a mycotoxin that is a threat to the health of animals and humans
DeWolf said that visual symptoms of Fusarium head blight include large tan lesions encompassing large portions of the developing wheat head. Close examination of the heads often reveals a chocolatey-brown color on the stem, and orange masses of fungal growth on the edges of the glumes.
At harvest, he adds, the kernels may be white and chalky, rather than a healthy amber color. The diseased grain is often shriveled and has a poor test weight.
“Many times, producers don’t realize they have a problem with it until they start harvesting their grain,” DeWolf said. “People start asking questions when they see the discolored, shriveled kernels in their loads of grain.”
Unfortunately, DeWolf adds, nothing can be done to suppress the disease at this point. In those fields where Fusarium head blight is present, the disease likely took hold in May. The state’s wetter weather during that time could have contributed to its spread this year.
“At this point, we are shifting over to making the best of an otherwise difficult situation,” he said.
That includes setting priorities, such as harvesting fields in which resistant varieties have been planted.
“I would suggest making fields planted to moderately resistant varieties such as Bob Dole, Everest, WB4269 or Zenda a top harvest priority. Early harvest will avoid any additional weathering of that crop, plus help preserve the test weight and quality of fields that were less at risk to Fusarium head blight,” DeWolf said.
He added that growers may also plan on adjusting their harvest equipment to remove as many of the light-weight, diseased kernels as possible. “Adjusting the air flow on the combine may help improve test weight and avoid costly discounts to the grain at the point of delivery,” he said.
Growers with on farm storage may be able to separate the loads of grain to avoid mixing healthy wheat with the grain from fields with unacceptable levels of grain. DeWolf said that taking the time to segregate grain may help preserve marketing options in the future.
Growers who have questions about their wheat crop can contact their local county extension agent for more guidance. K-State Research and Extension also publishes weekly updates related to many Kansas-grown crops in its weekly e-Update from the Department of Agronomy.