Planting Date and Fluopyram Seed Treatment Effect on Soybean Sudden Death Syndrome and Seed Yield

Planting date did not consistently influence sudden death syndrome development. Fluopyram use led to increased yield in the highest symptom environment recorded in this study. This study suggests that utilizing fluorpyram seed treatment can help maximize soybean yield. A new commercially available fungicide seed treatment, fluopyram, has potential for allowing producers to utilize optimal soybean Glycine max (L.) Merr. planting dates while simultaneously reducing the impact of sudden death syndrome (SDS). A study was conducted in 2015 and 2016 at three locations throughout Wisconsin (Arlington, Hancock, and East Troy) to examine interactions between planting date and fluopyram seed treatment use on SDS symptom development and soybean seed yield. Three seed treatments: (i) non‐treated (control); (ii) EverGol Energy + clothianidin + Bacillus firmus (Poncho/VOTiVO, P/V Bayer CropScience, Research Triangle Park, NC); and (iii) EverGol Energy + clothianidin + Bacillus firmus + fluopyram (Poncho/VOTiVO/ILeVO Bayer CropScience, Research Triangle Park, NC, P/V/I) were tested on two cultivars that differed in SDS susceptibility. Experiments at Arlington and Hancock were planted on three target planting dates (1 May, 20 May, and 10 June). In 2015, fluopyram use decreased disease index (DX) by 92% at East Troy and 82% at Hancock in the 1 May planting date. However, a 7% yield response (330 kg ha −1 ) from fluopyram use was observed only at the East Troy location in 2015 which had the highest level of foliar symptom development recorded in this study. In 2016, fluopyram use decreased DX at Arlington by 100% in the May planting dates while no visual difference among treatments was found in the June planting date. These results indicated fluopyram decreases SDS symptom development, but a positive yield response was only observed with high levels of SDS foliar symptom development associated with earlier planting dates.