Fusarium Head Blight Prediction Online for 2010

The Fusarium Head Blight Prediction Center is again up and running for the 2010 wheat growing season. I will be providing commentary on this site for Wisconsin similar to the previous growing seasons and this commentary often focuses on observations of all diseases we have noted around the state, and more importantly the current range of growth stages we have observed. Also, the U.S. Wheat and Barley Scab Initiative will be providing resources to help in communicating the current risk and situation across the wheat growing region. Some additional resources that may be of help as you access this site as well as determine the need for foliar fungicides for control of Fusarium head scab include:

1) Understanding the Fusarium Head Blight Prediction Center

2) Check Your Wheat Closely

Feel free to contact us with any questions and we will provide further updates as the conditions warrant.

Management of Small Grains - Fungicide Efficacy for Control of Wheat Diseases, Updated

We have been receiving several questions about the use of foliar fungicides for wheat. To provide further information regarding relative efficacy of foliar fungicides in wheat, the NCERA 184 (North Central Regional Committee on Management of Small Grain Diseases) recently updated their information of fungicide efficacy for control of certain foliar diseases of wheat. Efficacy ratings were based on field testing of materials over multiple years and locations by members of the committee. Efficacy is based on proper application timing to achieve optimum effectiveness of the fungicide as determined by labeled instructions and overall level of disease in the field at the time of application. Differences in efficacy among fungicide products were determined by direct comparisons among products in field tests and are based on a single application of the labeled rate as listed in the table. The Table lists the most widely marketed labeled products and is not intended to be a list of all products. The information in the table is provided only as a guide and does not provide an endorsement for any product.

Any questions about the table can be addressed to Paul: esker@wisc.edu

Early Season Wheat Diseases

Winter wheat in Wisconsin is looking very good across the majority of our field trials. In some of these trials, we are already at the Feekes 4 (Zadoks 30, pseudostem erection) growth stage. This week, it was noted that there is some evidence of powdery mildew (see photos below courtesy of John Gaska) in some of these trials. This is an important period for some early-season management decisions (not just for foliar fungicides also). Specifically for decisions for disease management, it really starts with knowledge of the relative susceptibility of your wheat variety against powdery mildew. With that knowledge, a second step is to then determine how severe and where in the wheat canopy are symptoms of powdery mildew being noted. At Feekes 4-5, the recommendation for the use of a foliar fungicide is based on the appearance of symptoms of powdery mildew on the newest (i.e., upper) leaf. Scouting by examining approximately 100 leaves in a field from different locations. Assess the severity for each leaf by counting the number of powdery mildew pustules. If the average number of pustules is 10 or greater, this may indicate the need for use of a foliar fungicide. In most years, we often see symptoms of powdery mildew in the wheat canopy, but typically only in the lower canopy due to the microclimate and varietal differences. Disease management decisions at these earlier growth stages need to take into account the assessment of the most appropriate leaf material that may impact the flag leaf later in the growing season.

Photos from Arlington, WI (Courtesy of John Gaska, Dept. Agronomy). Notice that the primary location of symptoms are in the lower canopy. As discussed earlier, guidelines for the use of foliar fungicides are based on examination of the uppermost leaf.