WOOSTER, Ohio – Ohio growers following wheat planting after corn harvest should be mindful of the potential for head scab development in their crop.
Pierce Paul, an Ohio State University Extension plant pathologist, said that recurring disease problems – ear rot and stalk rot in corn in 2009 and head scab in wheat in 2010 – may pave the way for continuing issues if weather conditions favor head scab development during the 2011 growing season.
"Wheat and corn are both members of the grass family, and as such, are affected by some of the same pests and diseases, one of which being head scab," said Paul, who also holds an Ohio Agricultural Research and Development Center appointment.
Head scab, a major disease of wheat that affects the crop during the flowering stage, is caused by the same fungus (Fusarium graminearum) that causes ear and stalk rot in corn.
"So even if the cornfield into which wheat is planted did not have a major ear rot or stalk rot problem this year, the fungus still is present in the corn stubble left in the field after harvest. In addition we had high levels of scab and vomitoxin in some parts of the state this year largely because most of our wheat varieties are susceptible, spores hung around from the ear rot problem we had in corn in 2009, and favorable weather conditions promoted disease development," said Paul. "So wheat planted into this stubble is more likely to have a head scab and vomitoxin problem next year, especially if conditions are favorable."
The key message: plant wheat after soybeans, not after corn.
"The production practice is one of the best ways of minimizing losses due to head scab and vomitoxin in wheat," said Paul.
If it's essential to plant wheat following corn, Paul urges growers to plant a scab resistant variety.
"In addition, plow under the corn stubble before planting wheat and be prepared to apply a fungicide next year at flowering if the weather becomes favorable," said Paul. "These approaches will minimize, but will not eliminate the risk of head scab in wheat planted after corn."
Growers are encouraged to follow the OSU Extension Crop Observation and Recommendation Network (C.O.R.N.) newsletter for updates at http://corn.osu.edu or refer to the Wheat Fusarium Head Blight risk map tool at http://www.wheatscab.psu.edu.
According to the Ohio Agricultural Research and Statistics Service, 36 percent of the corn in Ohio and 43 percent of the soybeans have been harvested, far ahead of this time last year, as well as the five-year average. Wheat planting is also ahead of schedule with 30 percent of the crop planted to date.
Timely wheat planting results in good stand establishment and ample tiller development, and it reduces the risk of winter kill.