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December 6, 2019

First Case of Soybean Rust Confirmed in Brazilian Soybean Fields

Author: Michael Cordonnier/Soybean & Corn Advisor, Inc.

The Antirust Consortium in Brazil announced the first confirmed cases of soybean rust in commercial soybean fields in Brazil. The first case was reported by an agronomist with the Coagru Cooperative in the city of Ubirata, Parana. There had been some previous cases of soybean rust on volunteer soybeans, but this is the first case in commercial fields.

This is a late appearance of soybean rust in Brazil. Normally, the first cases are confirmed by about mid-November. The Antirust Consortium has been tracking soybean rust in Brazil for 14 years and only twice during that period have there not been any rust reported by the first week of December. Both of those years were over a decade ago, which was before the disease had spread across all the soybean producing regions of Brazil.

The 5-year average for the number of confirmed cases of soybean rust in Brazil on December 6th is 46. The five year average for the total number of confirmed cases of soybean rust in Brazil during the growing season is 431.

Soybean rust is the most serious soybean disease in Brazil costing producers on average US$ 2.8 billion per year in control cost and lost production. The main strategies for controlling soybean rust in Brazil include: a soybean free period to slow the spread of rust from one growing season to another, using early maturing soybean varieties, planting as early as possible, using varieties with improved resistance to the disease, and using recommended fungicides.

The extension service of the state of Parana (Emater) announced earlier last week that the first soybean rust spores had been detected in the southeastern part of the state. The spores were detected by the system of 240 collecting devices positioned around the state. Emater indicated that farmers should monitor their fields and as soon as rust is detected, they should be prepared to immediately apply an approved fungicide application.