A few years ago I went with a camera crew to a frightening little drugs town in north-eastern Peru, where the farmers mostly grew coca.
I assumed they would be violent and aggressive. Not at all: they were the ones who were scared.
Every week or so gangs of armed, drugged-out tracateros, or buyers, would erupt into the town, forcing the growers to sell their coca paste to them at rock-bottom prices.
"So," I asked, "Why don't you simply grow something that won't get you into trouble? Maize, or wheat, or something?"
As it happened, we were close to a little shop. The chief spokesmen of the coca growers took me by the arm and led me inside.
There were all sorts of foods and vegetables for sale, mostly imported from the United States or the EU.
He told me how much each item cost; it was clear that every one of them had been dumped on the market at a fraction of its real value.
"We're just poor peasants," he said.
"We can't compete. We can't afford to grow these things so cheaply."
The only commodity they could grow which wasn't fiercely undercut by the artificially cheap produce of Europe and America was coca.
