Issue No. 6, Article 6/May 4, 2007
Comparison of Fungicides Available for Fusarium Head Blight (Scab) Control in Wheat
Since I wrote last week's article on "Using the Fusarium Head Blight Risk Assessment Tool To Help Make Fungicide Application Decisions for Wheat" (issue no. 5, April 27, 2007), a new development in wheat fungicides has occurred. Bayer CropScience now has a section 2(ee) label recommendation that allows for a 3 fl oz/A + 3 fl oz/A mixture of Folicur and Proline fungicides for control of Fusarium head blight, and the company is offering a rebate to reduce the price of this mixture.
Combining Folicur + Proline is essentially making a tank-mix of the product Prosaro, which is currently under EPA review for registration on wheat. Prosaro has been tested in comparison with Folicur in wheat fungicide trials in Illinois and other regional states. Table 3 provides some data from these trials. According to the data presented, yields were not always improved greatly with the mixture compared to Folicur alone, and the yields of the untreated plots were often similar to the yields of the fungicide-treated plots. The amount of scab pressure, which tended to be low in most trials, will certainly play a role in the effect of the fungicide on yield. The Folicur + Proline mixture has shown to be very good at reducing DON (vomitoxin) levels in the grain, which may be the biggest improvement over Folicur alone; however, both the mixture and the stand-alone products are effective at reducing disease and DON levels. So the big choice may be not what to spray, but if a spray is needed. If the crop has good yield potential and conditions are favorable for scab, then spraying will likely be beneficial. Remember that the Fusarium Head Blight Risk Assessment Tool is available online to help with your decision.--Carl A. Bradley
Carl A. Bradley