Looking Ahead – Early Scab Forecast and Fungicide Labels
Shawn Conley
Winter wheat in southern Wisconsin is starting to head (Feekes 10.1) indicating we are ~ 7 days away from anthesis or flowering (weather dependent of course). Calendar wise this puts the WI wheat crop developmentally about 3 weeks ahead of normal. Anthesis is the last critical wheat management growth stage and accurate identification of this stage is important due to fungicide label restrictions as well as timing of fungicides for management of fusarium head scab. To better understand and identify the flowering growth stage, please check here for an UWEX YouTube Video.
Most commercial fungicide products are only labeled through Feekes 10.5 (full heading) and others have restrictions based on days to harvest. A partial summary of these products as well as those labels for head scab please access them here. Not all products may be listed and not all products (especially some generic forms of tebuconazole) may be approved in WI. It is important to always check the label for specific use requirements.
Our prediction for Fusarium head scab is based on the Fusarium Head Blight Risk Assessment Tool (please see below). In terms of Fusarium head scab risk as of today (May 8), pockets of medium to high risk are showing up in the western portion of the state, as well as a small pocket in the eastern portion of Winnebago and Outagamie Counties. The current increase in risk is most likely a function of the weather events of the past several days. Interestingly, when we checked the May 7 forecast map and did a 24 hour prediction, it did pick up the areas in the western portion of the state, although today’s risk is somewhat higher than the forecast was. There is a chance for rain today around the state before some drying patterns move in. The risk for FHB may remain higher over the next several days. However, since we are approximately a week from flowering in the southern portion of WI, these conditions can, and will change, so we will continue to monitory and update the risk information, and management recommendations as we near flowering.
