January 19, 2005 | By: Laura Skillman
PRINCETON, Ky.

With two years of crop damage due to head blight, a large number of farmers and crop consultants turned out recently to hear the latest information from the University of Kentucky College of Agriculture’s Wheat Science Group at its annual conference.

Fusarium head blight not only can damage the kernels but also can result in the crop containing mycotoxins especially deoxynivalenol, or DON, which can restrict use of diseased grain as a feed source.

Kentucky ’s 2003 and 2004 wheat crops were hit hard by the head blight and as a result millers and grain buyers have had to blend Kentucky wheat with grain from other states to ensure a safe DON level, said Chad Lee, UK Extension grains specialist.

With two years of damage, the disease is on the minds of most growers and Lee said that is why the UK Wheat Science Group focused much of its annual conference on management decisions surrounding the disease.

In 2004, Kentucky received an exemption for the U.S. Environmental Protection Agency, called a Section 18, to use the fungicide Folicur on wheat to help suppress the disease. Only 17,000 acres, or five percent of the state’s wheat crop, was sprayed in 2004 and that was in part due to the late approval of the Section 18, said Don Hershman, UK Extension plant pathologist.

Hershman said the state again will apply for a Section 18 for the 2004-05 wheat crop.

Producers need to be realistic about the use of Folicur, he said. It is not a control for the disease but rather suppresses it. Fields will still have some damage if they are infected with Fusarium even after using the fungicide.

Hershman said he recognizes that while it is not a silver bullet for the disease, it is better than nothing. He also noted that there are no new fungicides on the horizon.

“We are relying on the plant breeders to develop resistant varieties,” he said.

UK Wheat breeder Dave Van Sanford said that work continues on developing resistant varieties and there are a few that are showing good resistance. Identifying and developing resistance is a time-consuming process. Resistant strains from China as well as some developed in Missouri are being used in the breeding process, he said. This year, UK has field tested three experimental lines that are showing good resistance but more research needs to be conducted before a variety will be ready for public release.

Hershman also discussed the relationship between tillage practices and crop residue to Fusarium head blight. Corn residue can be a reservoir for the disease. Because of this, no-tilling behind corn would seem to be the worst thing to do, yet many farmers in Kentucky are doing that. However, research has shown that while there is a higher incidence of Fusarium and DON in no-till, it does not greatly increase it.

“The fear of Fusarium head blight and DON should not be the reason to shy away from not-tilling wheat behind corn if you’ve got a good reason to do it,” he said. “You’ve got to decide if the benefit outweighs the risk or the risk outweighs the benefit. If you’ve got good reasons to plant no-till and plant behind corn then you should go ahead and do it because the overriding risk factor is the weather.”

The Fusarium head blight prediction model developed at Pennsylvania State University was outlined by Erick DeWolfe. The model compiles data to help predict the likelihood of Fusarium infection. This was the first year the model was available and it continues to be refined to help farmers best determine when and if they may need to apply a fungicide to try to suppress a disease outbreak.

For more information on wheat production, contact your county Extension office.


Contact: 

Writer: Laura Skillman 270-365-7541 ext. 278

Contacts: Don Hershman, 270-365-7541 ext. 215;
Chad Lee, 859-257-3203;
Dave Van Sanford, 859-257-5020 ext. 80770