Organizing Committee


Poster Presentations


Poster Presentations


Preventive and postinfection control of Asian soybean rust with fungicides

Presenter: A. Marçon

All authors and affiliations: A. MARÇON, R. Geddens, G. S. Smith, and A. Selley. DuPont Agriculture & Nutrition, Stine-Haskell Research Center, Newark, DE

Although significant efforts are enabling improved management of Asian soybean rust (ASR) caused by Phakopsora pachyrhizi, effective control relies on fungicide sprays. Fungicides for ASR may be separated into two categories: preventive only, and both preventive and postinfection control. Misconceptions exist about strobilurins and triazoles in both categories. Field trials conducted globally showed triazoles provide both preventive and postinfection control, while strobilurins are preventive only. Punch™ (400-g/liter EC formulation of flusilazole) and azoxystrobin were tested for preventive and postinfection control of ASR at rates of 3 and 6.2 oz of product per acre, respectively. For the preventive assay, fungicides were sprayed at 1, 4, and 7 days before inoculation. For the postinfection assay, fungicides were sprayed at 1, 2, and 6 days after inoculation. With a preventive spray, both products performed well. With postinfection applications, however, only flusilazole controlled ASR, while azoxystrobin was inactive. Spray timing is difficult for preventive-only products, such as azoxystrobin, that must be applied before infection. But with flusilazole, which provides both preventive plus postinfection ASR control, growers have the performance and flexibility they will need to effectively fight ASR and produce maximum yields.

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