Stemming the spread of cacao pests and diseases

The safe movement of plant germplasm is a vital part of global crop and tree breeding, conservation and improvement programmes, whether it’s the collection of seeds from the wild to conserve in genebanks or the transfer of material between breeders.

Germplasm can be moved in several different forms (seeds, bare rooted plants, budwood, etc), but whatever form it takes, proper precautions are required to avoid unwanted extra passengers - pests and diseases that could be contained in the host plant.  

The movement of cacao in particular needs to be carried out carefully. Its pests and diseases are often confined to particular geographical regions, and outbreaks can completely destroy crops and devastate the incomes of affected smallholder cacao farming communities.

A local outbreak of witches' broom disease (Moniliophthora perniciosa) in the 1990's in the State of Bahia, Brazil, caused a decline of 70% in production. Imagine the devavstation if this fungus was unwittingly moved to West Africa, where 70% of the world's cocoa is produced, while trying to tap into the genetic diversity that is largely found in Latin America.

Bioversity has just updated the Technical Guidelines on the Safe Movement of Cacao Germplasm, which was produced by the Safe Movement Working Group of CacaoNet.  In the ten years since the last update, our knowledge of some pests and diseases has increased, changes have occurred in the level of risk, and detection techniques have improved.

Two diseases causing particular concern currently are frosty pod (Moniliophthora roreri) which is spreading in Central and South America and black pod  (Phytophthora megakarya) which is spreading in West Africa. Each of these diseases that attack the cacao pods can destroy 50-75% of the crop. 

Download the guidelines