A virus affecting cacao trees in West Africa may threaten the world’s supply of chocolate, which is made from the seeds of the tree.
About 50% of the world’s chocolate originates in West Africa, primarily in the countries of Ghana and Cote d’Ivoire, but the spread of cacao swollen shoot virus disease (CCSVD) in recent years has resulted in harvest losses of 15-50%, according to a news release from EurekAlert!
Scientists have been attempting to create crops that are more resistant to this virus for decades — since the 1930s — but efforts to do so have been unsuccessful, according to the National Library of Medicine.
This virus is spread by mealybugs, small insects that consume the buds, flowers, and leaves of cacao trees.
“The infection occurs when mealybugs acquire the virus from infected cacao or alternative host plants and deposit them in healthy cacao plants during feeding,” explains a research study on cacao sustainability published by PLOS ONE.
Benito Chen-Charpentier, professor of mathematics at the University of Texas at Arlington and author of the study, along with researchers from the Cocoa Research Institute of Ghana, Prairie View A&M, the University of Kansas, and the University of South Florida, began this study to find a way to slow the spread of the virus.
“This virus is a real threat to the global supply of chocolate,” said Chen-Charpentier. “Pesticides don’t work well against mealybugs, leaving farmers to try to prevent the spread of the disease by cutting out infected trees and breeding resistant trees. But despite these efforts, Ghana has lost more than 254 million cacao trees in recent years.”
Farmers can protect the trees from the virus by giving them vaccines, but the vaccines are expensive, and trees that have been inoculated tend to produce a smaller harvest of cocoa.
The researchers in the study developed a new strategy to vaccinate a limited number of trees within the group of cacao trees.
“Mealybugs have several ways of movement, including moving from canopy to canopy, being carried by ants or blown by the wind,” Chen-Charpentier said, per the news release. “What we needed to do was create a model for cacao growers so they could know how far away they could safely plant vaccinated trees from unvaccinated trees in order to prevent the spread of the virus while keeping costs manageable for these small farmers.”
The scientists used mathematical patterns to create a pair of models that would allow farmers to create a perimeter of trees vaccinated against the virus around trees that are not. These models would reduce the ability for mealybugs to jump from one tree to another spreading the virus.
“While still experimental, these models are exciting because they would help farmers protect their crops while helping them achieve a better harvest,” Chen-Charpentier said. “This is good for the farmers’ bottom line, as well as our global addiction to chocolate.”
Poor West African harvests have caused the global supply of cocoa beans to become more scarce, causing prices for cocoa products to surge. Per Bloomberg, cocoa prices are at their most volatile in almost 50 years as traders pull out of the market.
Cocoa futures have risen by about 160% already this year. On Wednesday, the price leaped by as much as 5.2% to $10,985 a ton, resulting in the highest 60-day measure of volatility since the 1970s, the outlet reported.
