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Source: BusinessGhana [summ. Mod.DHA, edited]$200m-World-Bank-loan

COCOBOD [Ghana Cocoa Board] will use part of a World Bank loan to rehabilitate plantations destroyed by cocoa swollen shoot, which causes drops in yields and kills trees. The disease has wiped out about 500 000 hectares of farmlands. A reduced cocoa output in the country is partly due to swollen shoot and aging plantations.

The funding will finance COCOBOD's rehabilitation of farms and help to enhance knowledge on the virus strains. The board will take over disease-infested farms, cut and replace sick cocoa trees, and supervise their growth to a fruiting stage before handing them back to farmers.

An earlier loan to rehabilitate aging plantations and those affected by the disease, originally meant to cover 156 000 hectares of plantations, benefitted more than 88 000 hectares of farmlands. Of these, 40 000 hectares are ready to be given back to farmers. Stakeholders say that rehabilitation efforts need to be aggressive as many farmers are affected.
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[Swollen shoot disease of cocoa (CSSD) caused by species of genus _Badnavirus_ can lead to severe crop losses. The viruses are thought to have been transferred to cocoa from West African forest trees. Symptoms vary with different viruses or strains and may include leaf banding; severe effects on shoots and roots resulting in serious dieback or even death of the tree; or no symptoms at all. The viruses are spread by several species of mealybugs (family Pseudococcidae) and may also be transmitted by grafting and mechanical inoculation. Transmission with pollen and via true seed is considered unlikely, but spread on seed surfaces cannot be excluded so far.

Disease management relies on phytosanitation and clean planting material. Most affected countries require the removal of all infected trees and their neighbours. Mealybugs are difficult to control, and native forests serve as pathogen reservoirs. Keeping replanted trees from becoming reinfected would be challenging under local conditions, thus ongoing breeding programmes for virus- or vector-resistant crop varieties are crucial. Cross protection against severe viral strains by mild strains is also being trialled (see link below).

As westward spread of CSSD in Ghana led to a serious outbreak with more severe symptoms in 2008 (ProMED post 20081030.3416), the possibility of the involvement of a new viral strain was considered. Ghana, Togo, Nigeria, and Ivory Coast signed an agreement to tackle the disease; subsequently molecular work has increased. The genus has recently been reorganised and now includes a number of species associated with the disease, replacing an initial single species name. Isolates from field samples (ProMED post 20171025.5404488 and links below) include a suspected causal agent of the rapid decline phenotype of CSSD.

Additional virus sequences were constructed by _in silico_ analysis of symptomatic field samples collected in West Africa (ProMED post 20180409.5734172). Whether these are associated with intact virus particles and thus represent actual infectious viruses involved in CSSD _in vivo_ will need to be verified by pathogenicity and epidemiology studies. Of all currently known CSSD-associated viruses, pathogenicity studies to prove infectivity in the host (according to Koch's postulates) have so far only been carried out with a single inoculum of cloned virus.

CSSD symptoms:, and
Mealy bugs:

Cocoa swollen shoot disease information:,, and
CSS viruses, mild strain cross protection:
CSS viruses, description and new species:, and
Virus taxonomy and current _Badnavirus_ species list via:
Pests of cocoa including CSSV vectors:
Information on mealy bugs: (with pictures)
- Mod.DHA]


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