Anthony Martin, Iowa Soybean Association, Ankeny, IA
Sudden death syndrome (SDS), caused by the fungus Fusarium virguliforme, has been one of the largest causes of soybean yield loss in Iowa. Another yield reducing pest is soybean cyst nematodes (SCN), Heterodera glycines. The objective of this study was to evaluate the efficacy of the seed treatment ILeVO (fluopyram) to control SDS and SCN and the effect on yield. Fifteen two-treatment on-farm replicated strip trials were conducted in 2015 and 10 trials in 2016. The two treatments had a base fungicide and insecticide seed treatment with and without ILeVO. Soil sampling for SCN was conducted in the spring and fall, SDS severity ratings were taken in early September. Georeferenced yield data were collected by farmers’ combines equipped with GPS enabled yield monitors. Across 15 trials in 2015, the average yield response to the seed treatment was 40 kg ha-1 (90% confidence interval 14 to 68 kg ha-1). The SCN counts were below the threshold in the majority of the fields, but the treatment significantly reduced SCN levels in the end of season samples. SDS severity was low in most of the fields, but in locations with high levels of SDS there was a significant reduction in disease levels. Yield responses tended to be higher in locations with greater SCN pressure. 2016 yield, SDS ratings and SCN counts will be presented later. This seed treatment can help farmers control two important pests at the same time in soybean production.