Organizing Committee


Poster Presentations


Poster Presentations

Florida fungicide trials for Asian soybean rust in 2005

Presenter: David Wright, University of Florida
Coauthor(s): J.J. Marois, Univ. of FL P. J. Wiatrak, Univ. of FL

Asian soybean rust (ASR) was found in the county and on nearby sentinel plots when fungicide treatments were first applied. No rust pustules were identified in the fungicide trial at early bloom when fungicide applications were made. Evaluations for disease incidence and severity began 3 weeks after first application of fungicide. Disease incidence was near 100% at the first evaluation on control plots and severity less than 4 (10-15%) on the Horsfall-Barrett scale. Best fungicides had no rust at the first evaluation while others ranged from 5 to 30%. Ratings made during the second and third week progressed rapidly on the control and less effective fungicide treatments. By the third evaluation, 8-9 weeks after first bloom, most fungicide treatments had 100% incidence with only tebuconazole (Folicur) and flutriafol (Impact) having less than 50% when applied two times. Defoliation was very apparent and differences in leaf area index were noted with better fungicides. It is apparent that ASR can be controlled with a good fungicide program if fungicides are applied early enough in the epidemic. The second fungicide trial had rust symptoms at the beginning of bloom when the first fungicide application was made. These results will be reported on via poster presentation at the symposium.

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