Organizing Committee


Poster Presentations

Poster Presentations


Evaluating foliar fungicides for control of Asian soybean rust in Alabama, 2008-2009

Presenter: D. P. Delaney

All authors and affiliations: D. P. DELANEY (1), E. J. Sikora (2), K. S. Lawrence (2), M. A. Delaney (2), M. Pegues (3), J. Jones (3). (1) Auburn University, Agronomy & Soils, Auburn University, AL; (2) Auburn University, Entomology & Plant Pathology, Auburn, AL; (3) Alabama Agricultural Experiment Station, Gulf Coast Research and Education Center, Fairhope, AL

Soybean fungicide trials were conducted at the Auburn University Gulf Coast Research and Education Center in order to determine the relative effectiveness of foliar fungicides against Asian soybean rust (ASR) and other foliar diseases. Soybeans were planted in early June and then sprayed with varying fungicides and sequential treatments, starting at the R2 (full bloom) or R3 (early pod) growth stage. Treatments were applied with a high-clearance sprayer in 18 gal/A. Soybean foliar diseases were rated weekly beginning at the R6 to R7 growth stage. In 2008, ASR was first observed in the trials in mid-September in the lower canopy of untreated plots. Fungicides reduced ASR severity compared with untreated plots, with several differences noted. When initial application was delayed until the R3 growth stage, triazole fungicides were generally more effective against ASR than strobilurons, indicating some curative activity after initial infection had likely occurred. Treatments utilizing Topguard and Domark exhibited longer ASR suppression than other fungicides tested. Yields were adversely affected by prolonged wet soil conditions during pod-fill. Fungicide applications increased yield up to 8.6 bu/A in one trial compared with the check, while failing to statistically increase yield in two others. Similar trials were conducted in 2009 and results will also be discussed.

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