When Ray Schneider discovered soybean rust on a Louisiana State University research farm in early November, he sent digital images of the lesions and diseased plants to Glen Hartman and Monte Miles at the National Soybean Research Laboratory for their inspection. Based on their substantial experience with the disease, Glen and Monte suggested that the spores had likely been in the field for about four to six weeks. That night ZedX programmers ran the IAMS spore transport model for all active Western Hemisphere source regions and for all starting dates in August and September 2004. Model output suggested that the spores had been blown by winds converging into Hurricane Ivan during early September. The spores likely originated from rust infected fields in Columbia; however, the winds were such that the spores could have originated from the soybean growing region in northern Brazil and southeastern Venezuela. Soybean rust infestations have not been confirmed in this area. The next morning before Hartman and Miles left for Louisiana to join the Soybean Rust Rapid Response Team, we presented them with a predictive map of spore deposition to guide their scouting efforts. The map which was generated from the simulations that follow indicated that the area which likely received the heaviest deposition of spores was around Mobile Bay in Alabama where Hurricane Ivan made landfall. Louisiana appeared to be on the western border of the potential infected area. Model output suggested that spore deposition had occurred between central Louisiana and northeastern Florida and as far north as Tennessee and the Carolinas.

How to Interpret the Animation

The animation has 4 panels for each day of the simulation: [top-left] - viable airborne spores, [bottom-left] - airborne spores rendered non-viable by exposure to solar radiation, [top-right] - spores deposited on the ground by precipitation during that day, [bottom-right] total number of spores deposited on the ground during the transport event. For this model run, cohorts of spores were released on 6-9 September 2005 from the infected region in Columbia.

This text is replaced by the Flash movie.

Transport Model Details