Research proposes effective method for managing soybean rust

Last July, a study carried out at the Lagoa do Sino Campus of the Federal University of São Carlos (UFSCar) received the Award for Best Scientific Initiation Work at the 43rd São Paulo Phytopathology Congress, which took place at the Faculty of Agricultural Sciences of the São Paulo State University (Unesp), in Botucatu (SP). The study analyzed the effect of fungicides alone and integrated with biological control agents in the management of soybean rust, caused by the fungus Phakopsora pachyrhiz and considered the main crop disease, which can cause damage of up to 100% if adequate control methods are not implemented.

Currently, the main method of managing soybean rust used by producers is chemical control, that is, the application of chemical fungicides. However, the continuous use of fungicides has led to the development of fungal populations resistant to the main groups of fungicides available, which reduces the effectiveness of the products and can result in failures in disease management. 

"As we have been working in the area of ​​epidemiology and plant disease management for 25 years, we have always sought in our research to define the best ways to integrate management methods with a focus on technical, economic and sustainable criteria. Thus, in our understanding, plant disease management soybean rust must necessarily be integrated, as an isolated method will not result in success, as it is a highly aggressive pathogen", says Waldir Cintra de Jesus Junior, professor at the Natural Sciences Center (CCN) at Campus Lagoa do Bell and project advisor. "In this context, always seeking to help producers in solving their problems, we decided to carry out a project under field conditions to evaluate the effect of fungicides applied alone and integrated with biological control agents in the management of soybean rust", he adds .

The experiment was carried out at Fazenda Escola Lagoa do Sino, located on the UFSCar Campus Lagoa do Sino, from November 2023 to March 2024, in an area of ​​two hectares, which was divided into plots. One part received the application of fungicides (Mancozeb, Trifloxystrobin, Prothioconazole, Chlorothalonil, Epoxiconazole), the standard treatment used by producers; and the other part received the application of fungicides associated with biological control agents (based on Trichoderma asperellum e Bacillus amyloliquefaciens).

Based on the analyzes carried out, it was found that there was no statistical difference between the treatments in relation to the intensity of rust, that is, the intensity of the disease was the same when only chemical control (fungicides) was used and in the treatment that used integration of fungicides and biological control agents. "However, an extremely important result was that in the treatment with integration of fungicides and biological control agents, soybean productivity was higher, which demonstrates that biological control is an important strategy to be used in the integrated management of soybean rust", highlights the advisor.

According to him, the results obtained in the work are of great importance as they can directly help producers in minimizing the problem with rust, which is the main disease of soybeans. "We have proven that for efficient control of soybean rust, it is essential to integrate management methods. It is also important to highlight that the integrated management proposal that provided the best result of the work - integration of fungicides and biological control agents - is a measure practical, economical and accessible to the producer, allowing rationalization of the use of fungicides", concludes Waldir Cintra de Jesus Junior.

The work was developed by UFSCar Agricultural Engineering students Rodrigo Bielecki Jachinto, Giovanna Lorena Silva Zanni and Pedro Antevere Neto, with the collaboration of CCN professors Flávio Sérgio Afférri and Alberto Luciano Carmassi, and agronomist engineers Wellington da Silva Toledo, Kauê Ferreira and Vitória Costa Mingoranci.