University Response to Plant Health Label for Headline Fungicide

Paul Esker

Extension Plant Pathologist 

During the past winter, BASF was granted a supplemental Plant Health label for Headline® fungicide. In Wisconsin, the following crops are currently labeled: barley, corn, edible legumes, oats, oilseed crops, rye, and soybean. To date, there have numerous fungicide trials conducted at the University of Wisconsin in field crops like corn and soybean as well as winter wheat over the past few years, including trials that examine multiple active ingredients, different application timings, different crop rotations, and differences in genetics. These trials have included small plot research, small plot efficacy, and on-farm small plot and long strip trials. We have summarized results from these trials in the Wisconsin Crop Manager (Esker et al. 2009a; Esker et al. 2009c), the Proceedings of the Wisconsin Crop Management Conference (or Proceedings of the Wisconsin Fertilizer, Aglime, and Pest Management Conference) (Esker and Conley 2009; Esker et al. 2009b; Esker et al. 2009d; Esker et al. 2008; Grau et al. 2008) and various winter meetings. To date, the results from our trials have not shown a consistent response for use of foliar fungicides, except when the level of disease (i.e., higher severity) has warranted the application of a fungicide. Because of the lack of a consistent response it is difficult to predict the management conditions that will likely provide an economic response for many crops, especially corn and soybean. 

Specifically, the supplemental label indicates that improved plant health benefits from the application of Headline® may include:

• Host plant tolerance to yield-robbing environmental stresses like drought, heat, cold temperatures, and ozone damage

• Improved plant utilization of nitrogen

• Increased tolerance to bacterial and viral infections

• More specifically, for small grains, claims of improved straw strength and better harvestability

• In corn, improved stalk strength and better harvestability; induced tolerance to stalk diseases; better tolerance to hail; more uniform seed size

In response, 46 University research and extension specialists submitted a letter to EPA regarding the concern for the supplemental label. The letter is available for viewing at: http://www.epa.gov/opp00001/factsheets/final%20-epa%20letter2-13%20.pdf. Also, an excellent discussion of this issue is available in the Kentucky Pest News from February 24, 2009 (http://www.uky.edu/Ag/kpn/kpn_09/pn_090224.html#Corn). In particular, the primary theme of the letter is the concern over the broad statements made regarding the application of fungicides and the perceived benefit. Fungicides can have a physiological effect on plants, however, the main concern is that this label will be justification for the widespread use of foliar fungicides for reasons other than disease control and that this will increase the risk for earlier selection for resistance for some pathogens. Overall, I want to emphasize that the use of an IPM framework for disease management in field crops is most appropriate. Decisions should always begin with hybrid or variety selection and the use of an active scouting program is warranted before making any decision to apply a foliar fungicide. Applications should be made following the label recommendations and in a sound manner. 

Acknowledgements: I thank Chris Boerboom, Joe Lauer, Shawn Conley, and Bryan Jensen for their review, comments, and support of this article.

References:

Esker, P., M. Ballweg, G. Blonde, J. Bollman, J. Clark, D. Fischer, C. Hargrave, B. Halfman, S. Huntzicker, and B. Jensen. 2009a. Considering foliar fungicides for corn grain in 2009? Part I: A look at the results of on-farm fungicide trials from 2007 and 2008. Wisconsin Crop Manager, Vol. 16, Number 11, Pages 41-43.

Esker, P., M. Ballweg, G. Blonde, J. Bollman, J. Clark, D. Fischer, C. Hargrave, S. Huntzicker, and B. Jensen. 2009b. Summary of the 2008 strip trials for foliar fungicide use on corn. Proc. of the 2009 Wisconsin Crop Management Conference, Vol. 48, Pages 51-55.

Esker, P., G. Blonde, B. Jensen, J. Clark, M. Hanson, J. Bollman, T. Anderson, B. Halfman, and N. Schneider. 2009c. Considering foliar fungicides for corn in 2009? Part II: A look at results of on-farm fungicide trials from 2007 and 2008 for corn silage. Wisconsin Crop Manager, Vol. 16, Number 11, Pages 44-45.

Esker, P., B. Halfman, and B. Jensen. 2009d. Management decisions for foliar fungicides in corn. Proc. of the 2009 Wisconsin Crop Management Conference, Vol. 48, Pages 47-50.

Esker, P., and S. Conley. 2009. Integrated management for wheat diseases. Proc. of the 2009 Wisconsin Crop Management Conference, Vol. 48, Pages 43-46.

Esker, P., C. Grau, and B. Jensen. 2008. Foliar fungicides for corn. Proc. Of the 2008 Wisconsin, Fertlizer, Aglime & Pest Management Conference, Vol. 47, Pages 57-59.

Grau, C., P. Esker, M. Ballweg, J. Clark, D. Fischer, C. Hargrave, B. Halfman, S. Huntzicker, and B. Jensen. 2008. University of Wisconsin’s Corn Foliar Fungicide Trials Results. Proc. Of the 2008 Wisconsin, Fertlizer, Aglime & Pest Management Conference, Vol. 47, Pages 60-66.