The Moths that Could Destroy Colombia's Cocaine Trade

Efforts to fight the cocaine trade in Colombia have led to some drastic measures over the years, including a two-decade-long, US-financed process of spraying herbicide from the air. But last week, Colombia's government decided to end that project, and now a new idea for fighting the drug trade is starting to take flight: the release of thousands of cocaine-crazed moths into the jungle to eat the plants before they're harvested.

Most insects avoid coca plants because they can't break down the cocaine produced by the plant: at low doses it makes them sick and at high doses it kills them, according to a 2006 study in Gene. But the Eloria noyesi moth is unique in its ability to digest the leaves of the coca plant without harm. In fact, not only can the E. noyesi handle coca, it actually prefers it and specifically seeks out the plants to lay its eggs. The moth is nicknamed "the Gringo," because it loves coca plants so much.

"When the caterpillars hatch, they eat the leaves of cocaine but not of other plants," Alberto Gomez Mejia, the director of the Quindio Botanical Garden who originally proposed the idea back in 2002, told us in Spanish. "In this sense, they're very easy to control."

Mejia's idea is to release thousands of the small moths into targeted regions where coca is commonly grown, and let them devour and destroy the plants. It would be a long-term project, as each generation of moths would consume any new coca plants that replace the old crop. Though the idea is more than 10 years old, it's being re-considered in light of the Colombian government's decision this week to stop spraying the herbicide.

And it's not as crazy at it might sound at first: having insects eat up trouble crops (usually weeds) is a tried-and-true method of naturally controlling invasive plants, according to Anthony Shelton, an entomologist at Cornell University and an expert in biological control.

"There are cases upon cases of very successful weed biological control. It's a much more permanent solution to the problem," Shelton told me over the phone. He pointed to a number of examples where insects had been used to wipe out unwanted plants, including a moth that helped pare back an invasive species of cactus in Australia, and beetles that helped control the spread of St. John's Wort in California.

But Shelton said tests have to be done before unleashing an insect. Researchers need to make sure the moths won't branch off and start eating other kinds of native plants. He told me it's a fairly straightforward test: you put the insect in an environment where it only has access to one of the other, similar plants that grow in the area of the unwanted species and repeat the process for a variety of different plants. If the larvae die instead of eating the plant, it's a good indicator that they can only survive on their preferred food. And since a lot of insects are monophagous (meaning they only eat one kind of food), there's a good chance these moths might exclusively eat coca plants, he said.

"The alternative is using herbicides, which can leach into groundwater and can affect non-target organisms," Shelton said. In fact health concerns were one of the main reasons why Colombian President Juan Manuel Santos decided to stop using the herbicide glyphosate: the World Health Organization had recently classified it as a probable carcinogen.

Insects could provide a natural, long-term, and low-maintenance solution to the problem, Shelton said.

"From an environmental standpoint, if you can get a moth that's really specific for just this particular target, that's a hell of a lot safer than herbicides," he said.

Mejia told us the plan to use the moths is still just an idea, but one that he hopes President Santos will look into and maybe begin testing in small, controlled areas like national parks. Still, he said the E. noyesi is not a panacea for Colombia's troubles with cocaine trade.

"In my opinion, this is not exactly the best way to eradicate cocaine. The best way is manual eradication, to have the farmers abandon it and plant something else," Meija said. He told us coca continues to flourish in Colombia because it pays poor farmers a lot more than other crops. To really fight the drug war, there needs to be better incentives for farmers to steer away from growing coca, like better infrastructure and access to education, he said.

"Moths alone aren't going to stop this," he said.

Jason Koebler contributed reporting to this story.