Fungicide Use Evaluated, Summarized in Soybeans

In the recent Iowa State University Integrated Crop Management Newsletter, XB Yang and his associates summarize six years of fungicide research on soybeans. Their research appears to be exhaustive, examining up to 50 treatments replicated four times in a year. Obviously, the summary of data relates directly to Iowa, but I believe there is some applicability in Ohio.

Their study found that some soybean fungicide treatments consistently ranked top in terms of increase in yields in our multiple year tests (except for one season) even when disease pressure was low to moderate. Also, they found that application at R1 or earlier did not pay off, but application at R3 consistently produced highest yields. They summarize their study by stating that fungicide application is best reserved for seasons when foliar diseases are severe. The full Iowa State University article is available here.

In local research, Gary Prill and I have conducted three years of similar research at Farm Focus. Our findings are consistent:

2006: We compared separately Quadris, Headline, and Presto (foliar fertilizer) to an untreated check. Fungicide application was made at soybean growth stage R3. The Headline treatment provided a statistically significant yield increase compared to the Quadris, Presto and untreated check. The application of Headline paid for itself and provided an economic return in 2006. Study available here: http://farmfocus.osu.edu/bean_plant_health-06.pdf

2007: We compared separately Stratego, Headline and Presto (foliar fertilizer) to an untreated check. Fungicide application was made at soybean growth stage R3. The Headline treatment provided a statistically significant yield increase compared to the Stratego and untreated check. The application of Headline paid for itself and provided an economic return in 2007. Study available here: http://farmfocus.osu.edu/bean_plant_health-07.pdf

2008: We compared separately Domark, Headline and Stratego to an untreated check. Fungicide application was made at soybean growth stage R3. None of the treatments provided a statistically significant yield increase when compared to the untreated check even though the Headline and Domark treatment increased yield over the check. (Unpublished at the time or writing this blog post)

It is clear from three years of data that using fungicides on soybeans as a preventative measure may provide a net return in some years. In none of the three study years at Farm Focus was soybean foliar leaf disease present at levels that would have justified a fungicide treatment.

Full podcast available here:

12/18/08 Update:

XB Yang contacted me and provided a link to the full presentation.  He indicates the presentation is available for use, except for the photos (which are copyright protected). Full presentation available in a pdf file here.