Risco climático para ocorrência da ferrugem asiática da soja no Brasil

Abstract

Asian soybean rust is, currently, the most serious disease that affects the culture in the world. In this sense, this work aimed to evaluate the climatic risk for the occurrence of Asian soybean rust in the main producing states in Brazil. And check which months of the year are more favorable for the occurrence of temperature and relative humidity of the air to the development of the pathogen. Hourly data were collected from automatic weather stations in 179 locations, located in the states of Rio Grande do Sul, Paraná, Mato Grosso, Mato Grosso do Sul and Goiás, from the foundation date to december 2021. The climate risk values for the occurrence of Asian soybean rust were calculated daily, obtained by the product of the functions of response to leaf wetness duration, and air temperature during this period. The data were organized into monthly and annual averages for each meteorological station, being analyzed in boxplot graphs to compare the months throughout the year and verify which variable has the greatest influence on the total risk. In addition, a line graph was drawn from the monthly average of all stations in each state, to compare the different states considered in this study. Finally, quarterly maps were prepared for the spatialization of the results. Relative air humidity was the meteorological element with the greatest risk for the development of the disease in southern Brazil, with air temperature being the most limiting factor. The opposite was found for the states of the Midwest region. On average throughout the year, the state of Mato Grosso had the highest total climatic risks of asian soybean rust, followed by Paraná and Rio Grande do Sul. Goiás and Mato Grosso do Sul had lower risks. During the crop cultivation period, the highest risks were verified in Mato Grosso, while in the off-season they are higher in the South region of Brazil and lower in the Center-West.