Ecuador has taken to the Organization of American States (OAS) its challenge to Colombia's crop-spraying programme of coca plantations along their border.
Ecuador says the herbicides cause damage to legal crops
Ecuador's Foreign Minister Francisco Carrion has described the programme as a hostile act.
The Ecuadoreans argue that Colombia's aerial fumigation destroys crops and poses serious health risks on their side of the border.
Colombia says the programme is vital to combat illegal coca production.
It targets plantations controlled by drug traffickers and the left-wing rebel group Revolutionary Armed Forces of Colombia (Farc).
Colombia stopped spraying a 10km (six-mile) buffer zone a year ago after Ecuador complained that herbicides had drifted across the border.
But the Bogota government later resumed fumigations in the area following an increase in coca production there.
Colombia remains the world's largest producer of cocaine, although its share has dropped to 54% from 74% in 2000.
Its drug-eradication programme is supported by the US.
The OAS has mechanisms to settle disputes between member states.