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Poster Presentations


Poster Presentations

Florida Soybean Sentinel Plots for 2005.

Presenter: James J. Marois, Dept. of Plant Pathology, University of Florida
Coauthor(s): David L. Wright, Dept. of Agronomy, University of Florida. Carrie L. Harmon, SPDN, University of Florida. James Walker, Florida Cooperative Agricultural Pest Survey-Division of Plant Industry

A series of 26 sentinel plots were established in March of 2005 to monitor for the occurrence and development of soybean rust (Phakopsora pachyrhizi) in Florida. Each 15 m 15 m plot was planted to MG3, MG5, and MG7 soybeans. The 6 plots south of Lake Okeechobee never developed disease. The first sentinel plot found positive for soybean rust was in Marion County (Central Florida), on June 29. It was also the first sentinel plot to become positive for the United States and the plot furthest south to become positive. The next plot to become positive was in Escambia County (Western Florida) on July 18. Most sentinel plots became positive in August. Ultimately, all of the sentinel plots became positive from Marion County to Escambia County accept for Madison County (North-central Florida). In Madison County rust was detected in a nearby commercial field. In every positive plot, the disease was first observed on the MG3 plants. After first detection, plots were sampled weekly by taking 100 leaflets from mid-canopy. In general, it took about 4 weeks after detection before the disease began to reach a logarithmic growth phase. In 2005 Florida experienced a wet spring/early summer but in the middle of August it turned dry, slowing the advance of the epidemic in the sentinel plots. In 2005 the soybean sentinel plots were very effective in detecting early occurrence of soybean rust.

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