Cacao pests and diseases
A large share of the world cacao crop is lost between flowering and harvest. These are the threats that decide where cacao can be grown profitably — and which of them a farm meets depends almost entirely on which continent it is on.
Almost none of these are global
Black pod is the exception: it is found in every producing region. Everything else on this page is regional, and the regions barely overlap. Frosty pod rot has never been recorded in West Africa. Swollen shoot is a West African virus. Vascular streak dieback is confined to Southeast Asia and Melanesia. Witches' broom reshaped the Americas and is absent from Africa and Asia.
So a sentence like “cacao is threatened by witches' broom” is wrong for roughly three-quarters of the world crop. Every page here states where the threat is and where it is not, and the absence is recorded as a fact rather than left as an omission.
No figures for losses, and no treatments
Published yield-loss estimates for these threats vary by an order of magnitude between studies, seasons, regions and management regimes. A single percentage would be read as the answer when it is a description of one study, so these pages state the mechanism and the direction and say where the uncertainty is.
Nor is there any product, rate or spray interval anywhere in this section. Management is described as categories of response. This is a chocolate reference, not an agronomy service, and a treatment recommendation reaching a grower through it would be both useless and unsafe.
Oomycete disease
Fungal disease
Witches' broom
A fungus that hijacks the tree's own growth, producing the deformed shoots it is named for. Its arrival in Bahia in the late 1980s collapsed one of the world's major producing regions within a decade — the clearest demonstration in cacao's history of what a pathogen can do to a monoculture.
BranchesFlower cushionsPodsFrosty pod rot
A pod disease of the Americas whose worst feature is that it is not visible until too late: the fungus destroys the beans internally while the pod looks sound, and by the time the characteristic white bloom appears the pod has already produced enormous quantities of spores.
PodsVascular streak dieback
A fungus that grows inside the water-conducting tissue and kills branches from the tip back. Confined to Southeast Asia and Melanesia, it is the region's defining cacao disease — and it changed its own symptoms around 2004, which is unusual enough to be worth knowing.
LeavesBranchesVascular system
Viral disease
Insect pest
Capsids and mirids
Sap-feeding bugs whose feeding punctures kill patches of tissue on shoots and pods. The principal insect pest of West African cacao, and the damage compounds because the lesions they leave are entry points for fungi.
BranchesPodsLeavesCocoa pod borer
A small moth whose larvae tunnel through the pod interior and glue the beans together, so that a pod which looks acceptable from outside yields beans that cannot be separated or properly fermented. The principal insect pest of Southeast Asian cacao.
PodsStored beansMealybugs
Small sap-feeding insects that cause modest damage themselves and transmit cacao swollen shoot virus. They are the reason a virus problem in West Africa is also an insect problem, and the reason ants enter the discussion.
BranchesTrunkPodsFlower cushions
Vertebrate pest
By what it attacks
The practical cut across the biological one. A pod problem costs this season's crop; something that takes the trunk or the vascular system costs the tree and the decade of growing it took. Threats appear more than once where they do more than one thing.
- Pods
- Black pod, Witches' broom, Frosty pod rot, Cacao swollen shoot virus disease, Capsids and mirids, Cocoa pod borer, Mealybugs, Rodents, squirrels and other vertebrates
- Flower cushions
- Black pod, Witches' broom, Mealybugs
- Branches
- Witches' broom, Vascular streak dieback, Cacao swollen shoot virus disease, Capsids and mirids, Mealybugs
- Vascular system
- Vascular streak dieback
- Stored beans
- Cocoa pod borer
These pages exist because disease pressure is one of the real reasons a bar from one origin costs what it does, and one of the reasons some origins have nearly disappeared from the market. For what that means downstream, see economy and sustainability and the origin pages.