Looking Ahead – Early Scab Forecast and Fungicide Labels

Winter wheat in some areas of Wisconsin is starting to head (Feekes 10.1). With the warm weather we are currently experiencing, it is expected that the wheat crop will remain ahead of 2009 conditions and that we should soon seen evidence of flowering in portions of the state. To better understand the flowering growth stage, please check here for an UWEX You Tube Video by Shawn.

Additionally, I have begun to monitor more closely the forecast for Fusarium head scab and will be providing updates over the next few weeks, especially as we monitor our own studies for the current growth stages. In terms of our observations to date, powdery mildew is still the primary disease of note in the 2010 but there have been reports of Septoria leaf blotch, low levels of leaf and stripe rust, and some evidence of bacterial leaf diseases. The latter is one that we have few options for control (i.e., fungicides are not effective) at this point in the growing season.

In terms of Fusarium head scab risk as of today (May 24), it is low throughout the state and the risk remains low over the next one to three days.

As a reminder, paying attention to the wheat growth stage as we move into flowering is critical. Most commercial fungicide products are only labeled through Feekes 10.5 (full heading) and others have restrictions based on days to harvest. Below is a partial summary of many products and this can also be accessed 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.

Restrictions based on growth stage of Feekes 10.5 = Quadris, Headline, Tilt, Propimax, Bumper, Twinline, Quilt, Quilt Xcel

Restrictions based on a 30 day PHI = Caramba, Proline, Prosaro, Tebuconazole products (e.g., Folicur)

Restrictions based on a 35 day PHI = Stratego