On-Farm Evaluation of Fluopyram As a Seed Treatment for Sudden Death Syndrome (Fusarium virguliforme) Management in Nebraska Soybean (Glycine max) Production.

Sudden death syndrome (SDS, Fusarium virguliforme) of soybean is becoming more common in Nebraska soybean production. ILeVO® (ai: fluopyram, Bayer Crop Science) has been shown to have efficacy in managing SDS. The Nebraska On-Farm Research Network evaluated the effect of ILeVO® on SDS development and soybean yield at three locations in 2015 (near Fremont, Scribner, and Ulysses, NE) and at three locations in 2016 (near Sutton, Clay Center, and Peru, NE). Three seed treatments were evaluated: non-treated, base (fungicide, insecticide, and for some sites nematocide), and base + ILeVO®. Plots were a minimum of 9.14 meters by 314 meters with 4 replications of each treatment.  SDS incidence and severity were rated at two times, approximately 2 weeks apart at growth stage R4-R5. Yield was measured by weigh wagon for 2015 sites and converted to 13% moisture. In 2015, disease incidence was variable throughout the three locations with the highest incidence in Ulysses and Fremont, ranging from 5.7 to 31.1%. The Scribner location had low incidence (5% at the highest) and no treatments were statistically different. At the two 2015 locations where SDS was more severe, there was also a significant increase in yield of 202 – 269 kg ha^-1 at Ulysses and Fremont (p=0.1). Aerial imagery from the Fremont site showed higher NDVI for the ILeVO® treated seed.  Yield and disease incidence data from 2016 will be presented.  Preliminary data (2015 only) showed that when SDS is present in a field at higher levels, ILeVO® can be an effective treatment for both managing disease development and reducing yield loss; however, more research is need to determine a threshold level of SDS pressure that warrants the added costs of the fluopyram treatment.