January 4, 2011

Soybean Rust Slow to Appear in Brazilian Soybean Fields

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

Since its discovery in Brazil during the 2000/01 growing season, soybean rust has cost Brazilian soybean producers an average of US$ 2 billion per year in lost production and control costs. Thus far during the 2010/11 growing season, it appears that the disease has been very slow to invade Brazil's soybean fields.

Currently, Embrapa is reporting that 52 cases of the disease have been confirmed in Brazil and 35 of those cases have been in the state of Parana. The second most number of cases (10) has been confirmed in the state of Mato Grosso do Sul. Last year at this time, 343 cases had already been confirmed throughout Brazil.

Scientists and soybean farmers in Mato Grosso, which is the largest soybean producing state in Brazil, have not yet confirmed any cases of soybean rust in the state. The scientists believe that the extended dry season killed off many of the rust spores and that the weather pattern thus far in Mato Grosso has not been conducive for the reemergence of the disease in the soybean fields of the state. With the delayed arrival of the disease in the state, farmers in Mato Grosso will certainly spend less money on control measures in 2010/11 than they did in 2009/10.

This is all good news of course for soybean farmers in Brazil because controlling soybean rust has been the one production cost that has increased the most over the last decade. The disease was most costly to Brazilian farmers in the early to mid-2000s when at its worst point; the disease lowered the Brazilian soybean production by an estimated 5 million tons per year. Since then, Brazilian scientists and farmers have developed improved control measures to keep the losses to a minimum.

The ultimate solution is to develop soybean varieties resistant to the disease and there have been some recent successes. Embrapa scientists have found a gene that makes soybeans more tolerant to the disease, but the ultimate goal is to find multi gene resistance and Brazilian scientists feel they are close to doing so. In the mean time, they are advising Brazilian farmers to check their fields on a daily basis and be prepared to spray immediately as soon as the disease is reported in their area.