By DOUG GRAVES
Ohio Correspondent

COLUMBUS, Ohio — Warm, rainy conditions throughout Ohio has meant a superb season for corn and soybean growers. Not so for wheat growers in this state. Such weather conditions the first three weeks in June has resulted in an outbreak of wheat head scab, the worst the state has seen in nearly a decade.

“Incidence of head scab ranges from three to 61 percent, meaning that between four and 53 heads out of every 100 heads has some level of head scab,” said Pierce Paul, an Ohio State University Extension plant pathologist and small grains specialist.

A statewide survey of Ohio wheat fields shows incidence of head scab to be moderate to high in 70 percent of fields surveyed. The majority of the fields with greater than 25 percent head scab incidence are in the west central and northwestern parts of Ohio.
Head scab, or head blight, is a disease that attacks wheat during the crop’s flowering stage when conditions are just right. The disease not only affects yields, but the fungal pathogen produces a mycotoxin that is harmful to humans and animals if ingested.

“We’ve seen more head scab in some fields than we’ve seen the past 10 years,” Paul said. “I think that we are seeing higher incidences of head scab than normal this year partly because of the high level of ear rots we had in corn last year. More spores are carrying over from last year’s corn to this year’s wheat. Add to that favorable weather conditions and the fact that most of our varieties are susceptible, and you have all the makings for an outbreak.”

And Ohio wheat growers are not alone. Kiersten Wise, plant pathologist at Purdue University, says head scab is prevalent in Indiana as well.

“We are seeing scab in the northern part of the state, less in the southern sector,” Wise said. “Many fields in the northern part of Indiana have seen severe incidences of scab. A lot of factors go into this, like the flowering date, and how much rain those plants have received.”

According to Wise and others, the scab is present in many commercial fields in central and northern Indiana. The incidence, or number of infected heads, ranges from five to 60 percent or higher in areas of central and northern Indiana, with severity (amount of infection per head) ranges from seven to 40 percent in these areas.

In Illinois, wheat farmers have seen low incidence of wheat head scab.

“We had just 300,000 acres of wheat grown in Illinois this season, the lowest acres planted on record,” said University of Illinois Plant Pathologist Carl Bradley.

“Most of that wheat is grown in the southern portion of the state and from the fields I’ve inspected there was low incidence of head scab. It’s not an issue with our state in 2010, but it has been bad in previous years.”

Head scab can impact yield and can produce several mycotoxins (like vomitoxin) that affects grain quality.

Feeding infected grain to livestock can be harmful and using infected grain for bran, flour and germ can be unhealthy for human consumption.