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The Risk Map below applies to cereals in the most susceptible stages for infection.
For wheat that occurs at flowering (Feekes 10.51).
For barley flowering occurs around head emergence
Check the map below to see the predicted risk for your area of South Dakota.
This map indicates relative risk for scab based on weather data analyzed over the past 7 days and the forecasted weather for up to 3 days .
***Map Updated July 6, 2009** **Disclaimer**
SPECIAL COMMENTARY July 6, 2009
A little risk remains...
First let me apologize for the extended absence of a current forecast!! While I was out of the office for a number of days, we also ran into a family emergency and couldn't get the site updated until today.
Parts of the state have recieved abundant rainfall in the past several days, while other parts remain quite dry. All or nearly all of the winter wheat is past flowering stages however some northern spring wheat remains at risk of scab depending on rainfall patterns. If you have wet soils, heavy dew, and forecasted rainfall you may still experience some elevated risk of scab infection (if your wheat is flowering or nearly there).
Producers are reminded to continue monitoring the risk maps through flowering stages for their crops. Should you decide on a fungicide application, remember that strobilurin products (e.g. Headline, Stratego, TwinLine, etc.) are not recommended for application to heads if scab inoculum is present. Triazole products (Folicur, Caramba, Prosaro, etc.) are most effective against scab when applied at or just before flowering stage (but not before heads are fully emerged).
Just a few notes about scab: the disease is caused by a fungus (Fusarium graminearum) that enjoys warm, wet weather prior to and during flowering. If your crop is near heading or flowering, pay close attention. Cereals planted over corn residue are at somewhat higher risk because of the high levels of inoculum present. Winter wheat often escapes major infection. However some years when growth is delayed due to over-wet soils, or weather is particulary wet through heading/flowering, scab can occur at damaging levels. Check back regularly for further developments and updates.
For additional information, go to www.wheatscab.psu.edu - our partner forecasting site.
Click on a date below to view archived risk advisories from earlier in the season:
June 17, 2009 Archived Advisory
June 15, 2009 Archived Advisory
June 7, 2009 Archived Advisory
June 1, 2009 Archived Advisory
May 28, 2009 Archived Advisory
May 26, 2009 Archived Advisory
Legend for Map Colors:
Red High Risk Info Yellow Info Blue Info White Unknown Info
DISCLAIMER:This website and the risk advisory service contained within are offered free of charge to the public. The advisory was developed to provide wheat and barley growers with information to help them make more informed decisions about disease management. It is not intended that the advisory be used solely to schedule fungicide treatment, rather it is intended to aid growers and crop managers in that decision process. Understanding the relationship of weather/enviroment to scab development is one of the keys to implementing sound management strategies. The advisory is only a tool to illustrate the relative risk for scab development. The models used to develop the risk advisory are experimental. Any management decisions made based on the information contained herein are strictly the responsibility of the person or persons making such decisions. No warranty or guarantee is expressed or implied.
Links to return to:
SDSU Extension Plant Pathology Homepage
College of Agriculture & Biological Sciences
SDSU Plant Science Department
This page is maintained by the SDSU Extension Plant Pathology Project, Dr. Lawrence Osborne, Extension Plant Pathologist and Project Leader, SDSU Plant Science Department. ph (605) 688-5543.
Comments or Questions? Please feel free to email: Lawrence Osborne
Last modified: June 17, 2009
