AgroPages-Soybean rust develops partial resistance to fungicides in Brazil-Agricultural news

Soybean growers in the Brazilian state of Mato Grosso do Sul point out that the Asian rust developed gene alteration after fungicides application belonging to the strobilurins group. This finding was pointed out by director and researcher of the Chapadão Foundation, Edson Borges, who cited a statement from DuPont reporting the detection of fungus genome alteration in the position 129 - a mutation replacing the amino acid Phenylalanine by Leucine. This features "partial resistance", which indicates that the products may bring different performances when controlling the rust disease. The problem was announced in a meeting set by the Chapadão Foundation with farmers, farm managers and consultants from the Chapadão region that is in the border of the state of Mato Grosso do Sul, Goiás, and Mato Grosso.

The resistance was confirmed in a document sent by the Action Committee of Fungicide Resistance. The association is dedicated to the fostering of research and development with the recognition of FAO and the World Health Organization.The Committee highlighted on the other hand that among the population tested resistant individuals to the fungicides strobilurins have not been found, despite a report of a mutation in the position F129L mutation in the cytochrome b gene. Embrapa’s (Brazil's National Agricultural Research Company) quotation from the Anti-rust Consortium reveal that, however, it is verified that some products have diminished the performance throughout recent years.

Borges pointed that there are several solutions that can could be adopted, for example an increase of product dose, complementation with other fungicides, and rotation of products. According to him, however, the solutions would be accelerating new molecules registration from new chemical groups. For Borges, this is "a matter of national security", as soybean is Brazil’s main commodity and rust is the main disease of soybean which can cause losses up to 90%.