Why is the cacao tree under threat?
By 2017 up to 38 percent of the world's cacao harvest was being lost to disease each year, and a warming climate narrows the places the tree can live.
▶ Start the storyThe cacao tree faces trouble from two directions: disease and a changing climate. As of 2019, the cacao industry was under threat from the emergence of diseases, and by 2017 up to 38 percent of the cacao harvested each year was lost to disease. Parasitic organisms cause much damage to cacao plantations around the world.
up to 38%
Three diseases are known as the cacao disease trilogy: frosty pod rot, witches' broom and black pod rot. Frosty pod rot is one of the most serious problems for cacao in Latin America, and it is sneaky. Symptoms appear only 40 to 80 days after infection, so infected pods look healthy early on, which has led people to move infected pods unwittingly. In West Africa the cacao swollen shoot virus is spread from tree to tree by . It cuts yields by 25 percent in the first year and 50 percent in two, and usually kills the tree within 3 to 4 years. More than 200 million trees have been claimed, and Ghana has launched the most ambitious and costly eradication effort of any country against a viral plant disease.
Climate is the second pressure. In 2013 a paper from the International Center for Tropical Agriculture warned that Ghana and Ivory Coast, the two top cocoa growers, will see a decline in suitable areas as temperatures rise by up to 2 degrees by 2050. Severe droughts have already lowered soil fertility and yields, and some farmers have abandoned cocoa.
Scientists are working on it. In 2017-18 Mars and the University of California, Berkeley were using to adjust cacao DNA for hardiness in hot climates. But there is no easy fix: hardier hybrids sometimes gave bitter chocolate, and concentrating production in fewer varieties caused problems when disease struck.
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Recap
Disease and climate squeeze cacao, and fixes such as hardier hybrids have come with catches.
💡 A trick to remember it · Sick pods that look well, trees that cannot be banked as seeds: cacao needs living gardens and many varieties.
Surprising fact · Up to 38 percent of the world cacao harvest was lost to disease by 2017, and a pod with frosty pod rot can look healthy for 40 to 80 days.
Sources (6)
No source, no claim. Every fact in this lesson (15 claims) cites at least one of these.