“Growing the most scab-resistant varieties available may be the most important scab management decision,” said Fred Kolb, University of Illinois small grains breeder.
The U of I in recent years has screened wheat varieties for resistance to scab, or Fusarium head blight.
Research results are available online at http://vt.cropsci.illinois.edu/wheat.html.
There are a number of wheat varieties available in Illinois that are resistant or moderately resistant to scab, Kolb reported.
Scab can reduce wheat yields and result in poor test weights. And the fungus that causes the disease (Fusarium graminearum) can produce mycotoxins, such as deoxynivalenol (DON), that contaminate the grain, according to Carl Bradley, U of I Extension plant pathologist.
“Scab is one of the greatest threats to Illinois wheat producers,” Bradley said.
Variety selection should be combined with the use of fungicide at flowering for the best control of scab, according to Kolb. Sowing wheat into soybean stubble, as opposed to corn residue, also reduces the chance of a scab outbreak.
“A resistant variety and fungicide (even in research fields with high levels of scab) have been able to suppress the toxin below two parts per million,” Kolb said. “And that’s key because mills don’t want wheat over two parts per million with DON.”
The severity of a scab threat or outbreak is dependent on weather conditions at flowering. But Kolb advised farmers to take precautions now to minimize the risk of scab rather than react to an outbreak in the spring.
“Having genetic resistance with a fungicide (as a combination plan to manage scab) is better than either one individually,” Kolb said.
More scab research results generated by the U.S. Wheat and Barley Scab Initiative are available online at www.scabusa.org.
