New Fungicide Available to Combat Wheat Diseases

May 8, 2007

WOOSTER, Ohio -- A new fungicide has been introduced this season to help Ohio wheat growers in their fight against diseases.

Proline from Bayer CropScience has shown to be effective against diseases such as Stagonospora leaf/glume blotch, Septoria leaf blotch, tan spot and leaf rust. Proline joins six other fungicides made available to Ohio growers to control foliar diseases. They include Tilt, PropiMax, Headline, Quadris, Stratego and Quilt.

"Proline does very well in terms of controlling Stagonospora and leaf rust, two of the more problematic diseases in Ohio. We are testing it in trials this year to see how well it works against powdery mildew," said Pierce Paul, an Ohio State University plant pathologist with the Ohio Agricultural Research and Development Center. "As with other fungicide use, growers should scout fields first and then apply fungicide only when it's warranted."

Paul said that growers might be especially interested in Proline because of its effect against head scab, a serious wheat disease that attacks the plant during flowering under favorable moist conditions. The disease infects the wheat heads, causing shrunken, lightweight kernels, thereby reducing the quality and feeding value of the grain. The fungus that causes the disease also produces a chemical in the infected grain called vomitoxin that is toxic to livestock and humans.

"To date, Proline is the best fungicide we have for head scab control," said Paul, who also holds a partial Ohio State University Extension appointment. "But, despite its effectiveness, the important thing that growers need to keep in mind is that the fungicide doesn't cure scab and doesn't guarantee 100 percent control. Proline suppresses head scab, but it's not going to prevent it from occurring."

Paul said that the best results with Proline are observed when it is used in conjunction with variety resistance and when it is applied at flowering, using the correct nozzle setting. Growers should use the Fusarium Head Blight Prediction Center -- a Web-based forecasting model that predicts the level of head scab risk -- to aid fungicide decision-making for head scab control. The site can be accessed through http://www.wheatscab.psu.edu. The system is a joint project between Ohio State University Extension, Penn State University, Purdue University, North Dakota State University, South Dakota State University, and the U.S. Wheat and Barley Scab Initiative.

"If there ever was a time to use the head scab model, the 2007 growing season would be it. If growers choose to apply Proline to their wheat to control head scab, they need to use the model as a guide," said Paul. "Unlike other foliar diseases where you use visual symptoms as a threshold for fungicide application, you apply fungicides to protect the wheat heads against head scab during a time when there is no disease present on the plant."

Growers using the head scab model will see new additions to the site, including risk predictions based on 24 to 48 hours of forecasted weather, and commentary on the state of the wheat crop to help in fungicide decision-making.

Ohio's wheat crop is anticipated to begin flowering by the end of May or first week of June depending on planting date and variety planted.

For more information on Proline or other wheat fungicides, or to learn more about wheat management, refer to the Ohio State Agronomic Crops Team Web site at http://agcrops.osu.edu.

Author(s): 
Candace Pollock
Source(s): 
Pierce Paul