Climatic risk of drift occurrence in pesticide applications in Brazil

Brazil is the country with the highest consumption of pesticides in the world, with a high potential for causing environmental and economic damage. Spray drift is one of the main causes of environmental contamination by pesticides and can be intensified by adverse weather conditions. Based on favorable ranges of air temperature, relative humidity and wind speed, it is possible to estimate the time available for pesticide application, with a view to optimizing application efficiency and equipment use, as well as reducing the environmental impacts generated by spray drift. Meteorological data was obtained from the National Institute of Meteorology from all the automatic weather stations in Brazil, from which the risk of spray drift occurring in each location was estimated, as well as the influence of each meteorological factor on the composition of this risk. The risk values were grouped by Brazilian region, from which boxplot graphs were drawn up to check their monthly and hourly variation. The region with the highest average risk of drift was the North, while the South had the lowest rate. The monthly risk was highest in August and September in the Central-West region. In the hourly analysis, the highest risk occurred at 14:00 and 15:00 (UTC -3) in all regions. The meteorological elements with the greatest influence on risk were high temperatures in the North, low relative humidity in the Northeast, Midwest and Southeast, and high wind speeds in the South.