The virus, spread by unlubites, a hairy insect that thrives in hot climates, has been described as one of the "most ecologically devastating" viruses in the world. The virus has destroyed 50,000 hectares of cocoa farmland in Ghana, the world's second largest chocolate producer.
About 50% of the world's chocolate comes from Côte d'Ivoire and Ghana.
The virus was spread by tiny insects called mealybugs, which eat the leaves, buds and flowers of cocoa trees.
Ghana has lost more than 254 million cocoa trees in recent years, while about 20 percent of Ivory Coast's cocoa crop has been infected.
"This virus poses a real threat to the global chocolate supply," said Benito Chen-Charpentier, a math professor at the University of Texas at Arlington.
Farmers hope that by planting trees far apart, they can prevent unlubites from jumping from one tree to another and spreading the virus, he said.
