Recent weeks have been very hectic in terms of changes to the wheat foliar fungicide situation in Kentucky.  Much of what I am about to describe has its origin in EPA’s recent favorable response to a review of triazole chemistry. Without going into any details, new section 3 labels of triazole fungicides were held up for years due to questions regarding the environment and health risks associated with a common breakdown product of all triazole fungicides.  A favorable ruling by EPA in 2007 on this question opened the door for the section 3 labeling of new triazole fungicides. 

The Bayer fungicide, Proline (prothioconazole), labeled in the spring of 2007, was one of the first post-EPA-review triazoles to receive a section 3 label that could be used for disease management in wheat.  Then on April 21, 2008, EPA granted a section 3 label to two BASF fungicides containing the active ingredient, metconazole.  Caramba is straight metconazole and Multiva is a premix product of Caramba and Headline (pyraclostrobin). To my knowledge, neither of these products have received state approval as of this writing (May 7), but this should change shortly. However, due to the lateness of label approvals relative to the advanced stage of wheat development in Kentucky, it is likely that little or no Caramba or Multiva will applied to wheat in Kentucky this spring.

During the winter months of 2007-08, there was (again) considerable interest in seeking a section 18, emergency use,  label for Folicur to manage Fusarium head blight (a.k.a., head scab). However, due to the availability of Proline for this use, EPA made it clear that a section 18 was not a possibility this year. Then, in an odd twist of circumstances, it became clear that the supply of Proline available for use in Kentucky this spring was not sufficient to meet the projected demand.  As a result, the Kentucky Department of Agriculture issued a Crisis Exemption for Folicur on May 1, 2008 allowing the use of this fungicide for FHB management during the period May 1 through May 15. The next day, May 2, the announcement was made by Bayer that Folicur was granted a supplemental label to its existing section 3 label, which allows application to wheat and Barley in most states, including Kentucky.  Now, an additional tebuconazole fungicide, Orius, may be applied, but manufacturers of other tebuconazole fungicides have some additional hoops to jump though before that may be applied in Kentucky.

The Crisis Exemption for Folicur prompted Bayer to re-release a 2ee recommendation for the use of a combination of Folicur + Proline to manage FHB. However, since a shortage of Proline in Kentucky is the original reason for the Crisis Exemption, it seems unreasonable to expect that many producers will have access to enough Proline to be able to take advantage of Bayer’s 2ee recommendation.

If you need a copy of the Orius or Folicur labels, please contact us at info@kysmallgrains.org.

More information about Fusarium Head Blight

Written by Jennifer Elwell, KySGGA Director of Communications – 502/921-2625 or Jennifer@kysmallgrains.org

Source: Dr. Don Hershman, University of Kentucky Extension Pathologist