Winter Wheat Variety Trials Disease Assessments: We are currently in the process of examining the winter wheat variety trials that are at Arlington, Chilton, Janesville and Lancaster for foliar fungal diseases. So far, we have completed assessments at Arlington. The growth stage ranged from Feekes 9 (when the ligule of the flag leaf is visible) to Feekes 10.3 to 10.4 (almost full head emergence). From these assessments, the two main fungal diseases observed have been Septoria leaf blotch and powdery mildew. Tan spot has also been noted in some plots. However, we have also noted the presence of wheat leaf rust and wheat stripe rust. For these assessments, we measured the severity, which is the area of leaf tissue infected on the flag leaf and also the leaf directly below the flag leaf. For wheat leaf rust, symptoms were noted on 40% and 47% of plots on the two assessed leaves, respectively. Severity was as high as 10-15% in some plots. Wheat stripe rust was noted in only a few plots, and with only 3-4 pustules. We will continue to actively monitor for further rust development in the different wheat studies and locations.

 

Fusarium Head Scab Update: We are entering a critical period for wheat scab development in the state. The most up-to-date risk maps from the Fusarium Head Blight Risk Assessment Tool (http://www.wheatscab.psu.edu/riskTool.html) indicates that we have moved into a moderate to high risk in the southern portions of Wisconsin. In the past few days, we have seen temperatures move into the lower 80's with high humidity and heavy rainfall. As of our wheat assessments late last week, the growth stage ranged from Feekes 9 (when the ligule of the flag leaf is visible) to Feekes 10.3- 10.4 (heading almost complete). Flowering should be occurring during the next seven days or so, which is also the most favorable period for head scab development and vomitoxin accumulation. Growers should be actively scouting their fields, also for determination of wheat leaf rust and wheat stripe rust. Many of the current fungicides cannot be used after Feekes 10.5 or 10.5.2, so consult the label accordingly if you make a decision to spray. For example, the current labels for some of the representative fungicides indicate the following growth stages for last application:

Example product	Growth stage when last application can be made	Description
Quilt	Feekes 10.5	Full head emergence
Proline	Feekes 10.5.2	Wheat heads are in full flower growth
Headline	Feekes 10.5	Full head emergence
Stratego	Feekes 10.5	Full head emergence
Quadris	Feekes 10.5	Full head emergence

For the most up-to-date information regarding the current wheat development in the state, check http://thesoyreport.blogspot.com. For up-to-date risk prediction information for Fusarium head scab, check http://wheatscab.psu.edu.