The sky above Charras de Boquerón, a town in the middle of the Colombian jungle, is always pierced by planes filled with glyphosate. Each day they fly over thousands of plantations, searching for coca leaf crops to disperse the chemical. Behind them, they leave hectares of dead fruit and vegetable crops.
The coca leaf is unaffected.
"There's the coca leaf, nothing has happened to it," one farmer told VICE News. Beside him, the lawn was black and burnt, but the crop seemed untouched.
This super resistant crop is the boliviana mona, and it has been cultivated by most farmers in the Guaviare region since 2014.
"Almost ten thousand families rely on growing coca leaf in Guaviare," said Pedro Arenas, former mayor of San José del Guaviare.
Colombian president Juan Manuel Santos announced in May 2015 that the country would stop using glyphosate to destroy coca plantations, after the World Health Organization linked the chemical with cancer. Farmers told VICE News that the spraying has continued unabated.
This variety of coca is small, with green and yellow leaves, and red seeds. The last report on Colombian coca plantations produced by the UN Office on Drugs and Crime, or UNODC, and released on July 2015, states there are 13,981 acres of coca in the Guaviare department, which represents a 19.74 percent increase from the year before.
Most of the coca planted is of the boliviana mona variety, the report says.
The increase in coca plantations sparked alarm. In July 2015, Bo Mathiasen, the UNODC's representative in Colombia, said the South American country was on the way to snatching back the dubious honor of being the world leader in coca production from Peru.
The birth of stronger and more resistant varieties of coca leaf is not new.
"The farmers look for ways of improving the coca leaf varieties, they seek a more resistant and profitable coca, and they have been doing so for years," said Ricardo Vargas Meza, a sociologist who specializes in the study of illegal crops.
Vargas added that the Colombian government is missing this key point in the methods it uses to measure how much coca is produced.
"What they are doing is total nonsense, using satellites and aerial photography to measure the crops' area is not the problem," he said. "What they should really be doing is determining the productive potential."
Colombia's anti-narcotics police does not provide information on the boliviana mona, though it has registered the black, white, and red boliviana varieties in the country.
In Bolivia, the boliviana varieties are known as "Amazonian coca," and are known to thrive in warm tropical conditions with acidic soil. This fits perfectly with the conditions in the Guaviare region.
When the boliviana mona is ready to harvest, hundreds of raspachines — the workers who collect the leaves — go farm after farm, searching for work.
They place the leaves in plastic bags and take them to be weighed at what authorities call "drug laboratories" which are really little more than improvised sheds producing coca paste, which is the base for cocaine hydrochloride. Each raspachin earns a dollar for every 12 kilograms (26 pounds) of coca collected.
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Making coca paste involves chemicals, gasoline, and chopping up the coca leaves, leaving them for hours to dry. Mysterious drug lords — that everybody sees and nobody knows — come to town, buy the paste, and leave.
Farmers also use the small white rocks to pay for food and drink at the local market. They use it to give donations to the poor at church, or to pay for sex at the town's brothel. Coca is the local currency in Charras de Boquerón.
But coca has not made the town rich.
"Look at the roads, you cannot use them to exit town," said Juan, a farmer who has grown coca for decades and says it takes hours on the muddy and flooded tracks to get to his land. "You spend more money taking products to the nearest town than you get for selling them."
That's why Vargas, the sociologist, says the government should focus on roads, infrastructure, loans, education, and health; rather than on destroying crops.
"The main struggle must be against the poverty in those regions [that grow coca]," he said. "It is believed that coca is the problem when it's not."
The Colombian government is on the brink of signing a peace agreement with the Revolutionary Armed Forces of Colombia, or FARC. The first two agreements reached in negotiations between the rebels and the government in talks in Havana, Cuba, were a deal on replacing illegal crops, and another aimed at addressing historical injustices in the countryside.
It's highly probable that the guerrillas will have to eradicate illegal crops in their areas of control — Guaviare among them. The rebels have long used coca cultivation as a method of financing their war against the government.
For its part, the government has promised to turn its attention to the countryside with the aim of creating the conditions necessary to allow the estimated 10,000 families currently involved in coca leaf production to find alternative ways of making a living.
Follow Mario Zamudio on Twitter @mariozetap