Colombia is moving rapidly to revive aerial eradication of coca, but the chemical at the centre of its first proposed test will not be glyphosate, known commercially as “Round Up”.
The government of President Abelardo de la Espriella has approved a pilot programme to test the aerial spraying of coca crops with glufosinate ammonium, an herbicide that officials are presenting as an alternative to the Monsanto-manufactured compound.
The decision marks the most significant move towards the return of aerial eradication since Colombia suspended the practice during the administration of President Juan Manuel Santos. But the government still faces environmental, health and legal hurdles before the first plane – or drone – can take off.
Authorised through a resolution of the National Narcotics Council – and dated August 18 – the pilot project would last seven days and cover no more than 1,000 hectares.
The location has yet to be disclosed, with the government arguing that secrecy is necessary to protect personnel and prevent obstruction, sabotage or retaliation by illegal armed groups seeking to protect their laboratories and drug-trafficking routes.
The resolution nevertheless establishes restrictions. The operation cannot take place in protected environmental areas or in territories directly affecting Indigenous or Afro-Colombian communities unless the required prior consultation process has been completed.
Before any spraying takes place, the government must obtain an environmental-management plan from the National Authority for Environmental Licenses, or ANLA. The agency has previously authorised glufosinate for the eradication of illicit crops, but only for ground-based applications.
That distinction is central to the government’s experiment.
Glufosinate not glyphosate
Glyphosate and glufosinate are both herbicides, but they are different chemical compounds. Glyphosate became the focus of Colombia’s aerial eradication programme for decades before the practice was suspended in 2015 amid concerns over potential health and environmental impacts.
The International Agency for Research on Cancer, part of the World Health Organization, classified glyphosate in 2015 as “probably carcinogenic to humans”. Colombia subsequently suspended aerial spraying under Resolution 6 of 2015.
The De la Espriella administration derogated that resolution on August 28, reopening the legal possibility of aerial glyphosate spraying. This does not mean that glyphosate spraying will resume.
Instead, the government is pursuing a second track: testing whether glufosinate ammonium can be used from a low-altitude drone to target coca shrubs.
The distinction matters because the government is seeking to satisfy the constitutional and environmental requirements that have constrained aerial spraying since its suspension.
A technical assessment cited in the debate over glufosinate notes that much of the existing toxicological and environmental evidence concerns conventional agricultural use, where conditions such as climate, terrain and access can be relatively controlled. Those conditions differ substantially from aerial eradication operations in Colombia’s mountainous coca-growing regions, where armed groups, dispersed populations, legal crops and sensitive ecosystems complicate the assessment of risk.
Glufosinate is already used across large swathes of the Colombian agricultural lowlands, and has been authorised for ground eradication. But spraying it from a cropduster creates a different set of problems.
The government will have to assess the possibility of chemical drift, including the effects of wind on neighbouring legal crops, communities, waterways and endangered ecosystems.
The World Health Organization classifies glufosinate ammonium as a moderately hazardous pesticide. That classification has fuelled criticism of the proposal, particularly because replacing glyphosate with another herbicide does not automatically remove the health and environmental concerns associated with aerial spraying.
Its results are expected to inform a later decision on whether Colombia should adopt aerial glufosinate spraying more broadly.
The urgency behind the government’s decision is linked to the extraordinary expansion of coca cultivation. According to the latest United Nations monitoring figures cited by the government, Colombia had 260,000 hectares of coca in 2024, the highest figure recorded in the country’s history.
At the same time, forced manual eradication has fallen sharply. Between 2023 and 2024, when Gustavo Petro was president, manual eradication dropped by 54 percent, from over 20,300 hectares to 9,400 hectares.
For a new government that has made the fight against narcotrafficking and armed groups a central security priority, those figures have increased pressure to find an alternative. The incoming government’s decision therefore represents an attempt to restore an aerial component to Colombia’s eradication strategy without immediately returning to the controversial glyphosate programme of the past.
The question facing Colombia is therefore no longer simply whether aerial coca spraying will return. It is whether the country is prepared to replace one controversial herbicide with another — and whether glufosinate can withstand the environmental, health and legal scrutiny that ultimately brought glyphosate spraying to an end over a decade ago.
