Every six months over the past two decades, Pedro García has planted a small crop of opium poppies alongside the maize and beans in his hillside field. The modest profits from the flowers’ sticky sap – known in Spanish as goma – paid for his children’s schooling, but now, García, 50, can no longer eke out a living.

“I knew it was illegal, but I took the risk – and thanks to la goma I raised my family,” said García as he regarded the red, pink and purple flowers. “But now it’s over: my children are grown, the goma era is finished.”