The Chocaholic Mushroom

The pods of the tropical plant cacao, Theobroma cacao, are the source of chocolate. This crop is afflicted by a multitude of fungal diseases, including witches’ broom, frosty pod rot, and black pod. Until the mid-1990s, Brazil was second only to Côte d’Ivoire in cacao production. But then, the witches’ broom fungus, Crinipellis perniciosa, arrived, devastated the cacao plantations in Bahia, and Brazil dropped to fifth place among the cacao producing nations. The story of cacao diseases involves intriguing twists and turns, both scientific and geopolitical, including contemporary concern about the deliberate introduction of plant pathogens as acts of bioterrorism.