Organizing Committee


Poster Presentations


Poster Presentations


Plant disease control with glyphosate

Presenter: F. C. Kohn

All authors and affiliations: F. C. KOHN, G. J. Baley, G. A. Dixon, W. J. Duncan, P. C. C. Feng, K. A. Kretzmer, and M. A. Nishikawa. Monsanto Co.

Field activity of glyphosate against wheat rusts was demonstrated on glyphosate-tolerant wheat at Washington State University in 2002. Additional laboratory and field studies have confirmed glyphosate activity against Asian soybean rust (ASR), caused by Phakopsora pachyrhizi, in glyphosate-resistant soybeans and provided data demonstrating glyphosate activity against other plant diseases. Studies showed that glyphosate provides both preventive and curative activities against ASR. Application of glyphosate prior to rust inoculation delayed the onset of ASR. Glyphosate also displayed curative activity when applied within 6 days after rust inoculation. ASR activity was attributed to systemic glyphosate that required plant absorption and translocation, and little to no activity was observed with the surfactant system in a commercial glyphosate formulation. Field studies with Roundup® formulations have demonstrated reduction in ASR severity and increased yield compared to untreated controls. Our results indicate that glyphosate is active against ASR and could provide incremental disease control benefits in glyphosate-resistant soybeans.

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