Climatic risk for Asian soybean rust occurrence in Mato Grosso, Rio Grande do Sul and Paraná states

ABSTRACT Asian soybean rust is a primary factor affecting soybean production. Climate risk knowledge optimizes agricultural management, reduces pesticide use, and promotes environmental sustainability. The objective of this study was to evaluate the climatic risk of the occurrence of Asian soybean rust in the states of Mato Grosso, Rio Grande do Sul, and Paraná, Brazil, verifying the months with temperature and relative air humidity that are more favorable for disease development. Hourly meteorological data were obtained from the National Institute of Meteorology, collected from 36 automatic weather stations in Mato Grosso state, 44 in Rio Grande do Sul state, and 26 in Paraná state, from the beginning of the operation until December 31, 2021. The climatic risk values for Asian soybean rust occurrence were calculated daily, obtained by the product of the response functions to leaf wetness duration and air temperature during this period. The average total climatic risk of Asian soybean rust occurrence in Mato Grosso, Rio Grande do Sul, and Paraná states, was 44, 30, and 36%, respectively. Relative air humidity was the meteorological element with the greatest climatic risk for the development of the disease in the states of Rio Grande do Sul and Paraná, Brazil, and air temperature was the most limiting, the opposite was observed for the state of Mato Grosso, where air temperature was favorable and relative air humidity was more limiting.