We are entering a critical period for wheat scab development in the state. The most up-to-date risk maps 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 our our wheat assessments late last week, the growth stage ranged from Feekes 9 (when the ligule of the 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:
Quilt: Feekes 10.5 (full head emergence)
Proline: Feekes 10.5.2 (when 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)
The Soy Report Mission
To provide Wisconsin growers and agricultural clientele with timely crop management recommendations, diagnostics, and crop updates, both locally as well as around the region and world.
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WI State Soybean and Wheat Extension Specialist
Shawn Conley
The Soy Report: Awarded 2009 ASA Extension Educational Materials Certificate of Excellence
