Brazilian Commission reviews chemicals for soybean rust control

Brazilian farmers have been battling soybean rust in their soybean fields since the 2000/01 growing season when the disease was first identified in Brazil. The disease is thought to have originated in China and soybean rust (Phakopsora pachyrhizi) is the most serious disease facing soybeans. If left untreated, yield losses can be as high as 80%. Over the intervening years since it was discovered in Brazil, it is estimated that the disease has cost Brazilian farmers US$ 10 billion in control costs and lost production.

Brazilian scientists and farmers have been reporting in recent years that many of the chemicals currently being used to control the disease have been losing their effectiveness due to the disease developing resistance. As a result, scientists have urged farmers to rotate their chemicals so that they are using different modes of action in order to slow the development of even more resistance.

A recent meeting in Brasilia of the Technical Commission for the Agronomic Reevaluation of Agricultural Chemicals used to Control Soybean Rust is part of the process to identify better ways to control the disease. So Noticias reported that the Commission met earlier this week at the Ministry of Agriculture to evaluate the research findings concerning 126 chemicals and their potential use in controlling the disease.

The chemical companies had to defend the effectiveness of their products within the guild lines of the Commission which is composed of scientists from Embrapa, the Brazilian Phytopathology Society, the Brazilian EPA, the Brazilian Soybean and Corn Producers Association (Aprosoja) and others. As a result of their evaluations, some of the chemicals had their resgistrations revoked because they were no longer effective in controlling soybean rust, while other chemicals maintained their registrations.

The Commission was particularly interested in the chemicals active ingredients and their mode of action with the goal of potentially mixing together different chemicals in order to improve overall control. Different chemical mixtures are set to be evaluated in the field by Brazilian scientists during the next growing season.