We collected historic satellite remote sensing data from AQUA-TERRA systems and Landsat systems during 2003-2013. Based on limited disease data collected in Iowa and several locations in nearby states from 2009 to 2012, analyses showed that changes of canopy due to foliar diseases, including soybean brown spot, sudden death syndrome, and white mold could be detected by satellite imageries using Normalized Difference Vegetation Index (NDVI). Correlations of SDS occurrence with other indices of remote sensing imageries were analyzed as well. Historical SDS occurrence showed good correlation with the date of onset of greenness at a regional scale.
Using aerial remote sensing data in 2013 provided by the On-Farm Network, we examined the correlation of NDVI with soybean SDS and white mold occurrence on our research farms, which showed similar results to the results from historical data. Soil samples were collected from 48 fields with possibly different historical disease occurrence based on satellite imagery assessment to test the presence of SDS pathogen using a selective medium. However, the selective medium was not sensitive enough to detect difference of SDS pathogen presence in different fields. We are seeking for molecular biology approaches, which will be more sensitive in detection of SDS pathogen, and to repeat this examination in the 2014 growing season.