We propose a mathematical model for the Glyphosate aerial spray drift at the Ecuador-Colombia border. Glyphosate is one of the herbicides used by the Colombian government to spray coca fields close to the Ecuadorian border. The model considers the particular procedures of the sprays at the border as well as the topography and weather conditions of three zones of interest at the border. Two dimensional simulations are shown. The lack of reliable information constrains the accuracy of the model. However, the results presented in this work can be used as a starting point for more accurate models of the phenomena.