Biological control is an alternative to mitigate losses due to white mold in soybeans in the 20/21 harvest

The delay in soybean planting, which was marked by drought between the months of September and October, was practically reversed, according to the latest survey by the National Supply Company (Conab). In recent weeks, grain production in Rio Grande do Sul, one of the states most impacted by the lack of rain, managed to resume sowing, contributing to the record production estimate for the oilseed in Brazil, which should reach 134,9 million tons in the 2020/2021 harvest - an increase of 8,1% compared to last season.

With more favorable climatic conditions for crop development, especially in the southern region, some diseases can affect crop productivity at the beginning of the cycle. For Ricardo Brustolin, consultant and researcher at RB Consultoria, after the first 45 days of the emergence of most soybean cultivars, white mold (Sclerotinia sclerotiorum) has gained relevance in higher altitude productions in Rio Grande do Sul. "According to data from Embrapa, it is estimated that approximately 28% of the area designated for soy in the country is infested by the pathogen, that is, around 10 million hectares of cultivation", he reinforces.

White mold can attack soybeans in the germination and emergence phase, through the dormant mycelium in soybean seeds. However, the greatest damage occurs in the reproductive stages (from flowering to pod formation). "The disease can survive in the soil for several harvests in the form of sclerotia (pathogen resistance structures), which germinate and produce spores that are infective units. It mainly attacks the lower third of plants, in the lower reaches, requiring careful monitoring already in initial months of cultivation", adds Brustolin.

According to the researcher, once the plant is infected by the fungus, curative control and isolated measures are not efficient, hence the importance of Integrated Disease Management, aiming to reduce the impacts on the soybean farmer's profitability. "To combat white mold in crops, it is necessary to apply preventive and planned measures. The combined use of chemicals and biologicals, for example, has proven to be an option. Biofungicides can be applied in the vegetative stage of soybeans (at V3 and V4 ) and with the action of microorganisms, natural enemies of the disease, the white mold sclerotia decrease in the soil, promoting control of the inoculum source", he adds.

This diversification brings a series of advantages to the production system, such as: increasing diversity in control and reducing the chances of the emergence of resistance in organisms. White mold is a disease that can attack all organs of host crops, that is, "normally, lesions occur in the aerial parts of plants, in addition to the growth of a white, cotton-like mycelium. Over time, The branches, leaves, pods and stems rot, which can cause the death of the plant", concludes Brustolin.

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To help soybean farmers deal with this problem, Bayer offers some solutions that allow for intelligent management, which are: fungicide Fox Xpro and microbiological bactericidal fungicide Serenade.

The biological solution has multiple modes of action. So, with the application of Serenade, lipopeptides produced by Bacillus subtilis QST713 starts to act on the cell membrane of the fungus' reproductive structures, causing its deformation and producing ruptures. O Bacillus subtilis it also acts by competing for space and nutrients on the plant surface of the plant and in the soil near the root system.

"Bayer's recommendation is that producers use integrated management, which combines biological and chemical control. Thus, soybean farmers can make use of Serenade as early as possible, to reach the stem and soil, close to the first application of Fox Xpro, aimed at preventive disease control", explains Cecília Melo, product launch manager at Bayer.

Launched by Bayer in 2019, the fungicide Fox Xpro It has a triple formulation, including the active ingredient Bixafem, the company's new carboxamide. The formula acts at different stages of the fungi's life cycle, providing health to the plants, which can result in better results at the end of the harvest.

According to Cecília, "in the last harvest, we closely monitored 3610 assisted areas, which represents 21% of the soybeans cultivated in Brazil. For every four areas analyzed, three had greater productivity with the use of Fox Xpro. In 45% of these areas, there was an increase of two to four bags per hectare and, an approximate general average, an increase of three more bags. This is because the consistency of the results Fox Xpro It's impressive, we had this average result not only in commercial areas, but also in contracted protocols and studies from recognized institutions*", concludes the manager.