Viral disease cuts cacao harvests by half as trade drops

Sunday May 12 2024

Some assorted chocolates at a shop in Nairobi, Kenya. PHOTO | FILE | NMG


Chocolate and related products are coming under threat from the Cacao swollen shoot virus disease (CSSVD), which has slashed some harvests by up to 50 percent.

Cacao, the primary ingredient in chocolate, is predominantly grown in tropical regions, with West Africa being a major producer. However, this region has been particularly hard hit by CSSVD, alarming chocolate producers and enthusiasts alike.

The virus, transmitted by mealybugs, attacks the cacao tree’s vascular system, causing swelling and stunting growth, and ultimately leading to the death of the plant.

The impact of CSSVD extends beyond just the loss of crops. It threatens the livelihoods of millions of farmers who rely on cacao cultivation for their income.

Read: Côte d’Ivoire, Ghana demand higher cocoa prices

Smallholder farmers, in particular, are vulnerable to the economic repercussions of failed harvests, as their livelihoods are often dependent on the success of their crops.


Fifty percent of the chocolate in the world originates from cacao trees in West Africa, notably Côte d’Ivoire and Ghana. In Ghana, it has resulted in harvest losses of up to 50 percent.

This month, in a publication titled, Cacao sustainability: The case of cacao swollen-shoot virus co-infection, Benito Chen-Charpentier, a mathematics professor at the University of Texas at Arlington, highlighted the severity of the situation.

He said traditional methods such as pesticides have proven ineffective against mealybugs, forcing farmers to resort to drastic measures like removing infected trees and cultivating resistant varieties. Despite these efforts, Ghana has witnessed the loss of over 254 million cacao trees in recent years.

In response to the threat posed by CSSVD, scientists and researchers are working to find solutions to combat the spread of the virus and develop resistant cacao varieties. Efforts are being made to identify genetic markers associated with resistance to CSSVD, with the hope of breeding cacao plants that are less susceptible to the disease.

Read: Agriculture is key to economic recovery in Africa

To combat the spread of the virus, farmers have explored vaccinating the trees. However, this approach comes with challenges as vaccines are costly, particularly for small-scale farmers, and vaccinated trees tend to yield smaller cacao harvests.

A team of researchers have devised models to determine optimal distances between vaccinated and unvaccinated trees to impede bug movement and prevent the virus from spreading.

By leveraging mathematical techniques, the team aims to provide farmers with guidance on planting arrangements that can safeguard their crops. While still in the experimental phase, these models offer promising prospects for protecting cacao plantations and improving harvest yields.

Additionally, measures such as improved pest management practices and the use of biocontrol agents are being explored to mitigate the spread of the virus. Collaborative initiatives involving governments, research institutions, and industry stakeholders are crucial in addressing this threat to the world’s chocolate supply.