Chocolate Trees Under Fungal Siege

Next time you scarf down a handful of M&Ms, don't take them for granted. The little morsels don't grow on trees. But the beans that produce chocolate do--at least right now. Cacao trees in Latin America, the prime source of U.S. chocolate, have come under heavy attack from fungal diseases.

The crisis is the result of years of planting monocultures and spraying them with pesticides, explains Marlene Machut, a researcher at M&M/Mars Inc., in Hackettstown, New Jersey. Growers around the world cultivate only three varieties of cacao, she says, because they usually can't afford breeding programs to create new fungus-resistant hybrids. And pesticides have devastated many helpful soil-dwelling predators that would otherwise keep fungi in check.

As a result, losses are reaching critical levels. "In some places in Latin America, losses of 100% are not uncommon," says economist Eric Rosenquist of the U.S. Department of Agriculture's Agricultural Research Service in Beltsville, Maryland. Bahia, Brazil, used to be the world's second-biggest producer of cacao, says M&M's John Lunde. But U.S. yearly imports from that region have plummeted from 430,000 tons to about 130,000 tons over the past 15 years. And in Africa's Ivory Coast, the world's top cacao grower, "there will be serious shortages in a few years" if the diseases are not contained, says Lunde.

Help may be on the way. Plant scientists from the United States, Britain, and Latin America have teamed up with chocolate manufacturers to plot counterattacks, such as introducing benign fungi to displace the bad ones and planting cacao between taller coffee trees that supply fungi-stopping shade. But those strategies may not pay off for a decade, says Rosenquist. In the meantime, chocolate lovers may want to take a bit more time to savor their treats, before they are in short supply.

Follow News from Science

A 3D plot from a model of the Ebola risk faced at different West African regions over time.
dancing shoes