Wednesday, November 15, 2006 - 9:15 AM
234-2
Epidemic and Spread of Soybean Rust in Florida/Sentinel Plots.
Soybean rust (Phakopsora pachyrhizi) (SBR) was first observed in North America in November, 2004. It is presumed to have come with the hurricane Ivan. In 2005 a series of soybean sentinel plots were established across the soybean producing states including Florida , to monitor its occurrence and development. The first sentinel plot found positive for soybean rust in the United States in 2005 was in Marion County (central Florida), at the end of June. It was also the plot furthest south to become positive. Most sentinel plots became positive in August. In all the positive plots, SBR was first observed on the earlier MG III plants first where MG III, V, and VII were planted. On average, it took about 4 weeks after detection for the disease to reach a logarithmic growth phase. In 2005, Florida experienced a wet spring/early summer but turned dry by the middle of August. The dry condition slowed the advance of the epidemic. The Florida sentinel plot program was successful in detecting SBR before it was detected in commercial fields. The sentinel plot program shows promise as a means to monitor the annual spread of SBR from south to north Florida and, in association with sentinel plots in more northern states, the potential annual spread of SBR into the Midwest.
Recorded presentation