When it got low, they got high. In the southern Peruvian Amazon, a cooperative of coffee farmers is seeking help as its coffee crop — considered among the world’s best — struggles against a spate of “yellow rust” fungus. Before 2011, coffee production never dropped below 11,000 tons; in 2014, it fell to 628 and hasn’t recovered much. And with coffee farming growing risky, more in Peru’s Sandia Valley have turned to coca. Now, organizations are scrambling to mount a counteroffensive, hoping alternate crops and reforestation can hold the line against cocaine traffickers.