ProMED
http://www.promedmail.org

Source: GhanaWeb [summ. Mod.DHA, edited]
https://www.ghanaweb.com/GhanaHomePage/business/More-than-43-000-cocoa-trees-destroyed-in-Dormaa-due-to-swollen-shoot-1406965

More than 43 000 cocoa trees affected by the swollen shoot disease have been destroyed on 106 hectares in the Dormaa area of the Bono Region. The figure represents almost 100% of the farmland affected by the disease in 2020. This was carried out under the Productivity Enhancement Programme (PEP), which aims to check the further spread of the disease and help restore the affected farms. Besides cocoa (_Theobroma cacao_), other tree crops that are hosts to the disease, such as kapok (_Ceiba_ spp.) and kola nut (_Cola_ spp.), were also destroyed to prevent disease spread.

The government pays compensation to both landowners and farmers. The district cocoa officer called for improvement of awareness of the PEP concept so more farmers would participate. He said that there was a lot of evidence that farms that had been worked are beginning to reap positive results.
--
communicated by:
ProMED
<promed@promedmail.org>

[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 and 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 CSSV.

Maps
Ghana:
https://cdn.britannica.com/75/5075-050-78E51BD5/Ghana.jpg
Ghana regions:
https://www.easytrackghana.com/images/maps/Ghana-new-regions.png

Pictures
CSSD symptoms:
http://www.dropdata.net/thamesvalleycocoa/CSSV_Andy_Wetten_s.jpg,
http://www.worldcocoafoundation.org/wp-content/uploads/CSSV.jpg,
https://upload.wikimedia.org/wikipedia/commons/e/ef/Cocoa_Swollen_Shoot_Stem_symptom.jpg,
http://ipsnews.net/pictures/20081127_SwollenShoots_HighRes.jpg and
http://www.dropdata.org/cocoa/cocoa_pics/CSSVD1s.jpg
Mealy bugs:
https://www.winebusiness.com/content/image/wv/wv_2009-06-03_bugs.jpg

Links
Cocoa swollen shoot disease information:
http://www.plantwise.org/KnowledgeBank/Datasheet.aspx?dsid=12380,
https://doi.org/10.1016/j.cropro.2014.07.001,
https://doi.org/10.1007/978-3-319-24789-2_10,
https://doi.org/10.1094/PDIS-03-16-0404-RE and
https://www.researchgate.net/publication/303332326_Minimizing_the_risk_of_spreading_cocoa_swollen_shoot_virus_disease
CSSV mild strain cross protection:
https://doi.org/10.1094/PDIS-09-15-0974-RE
CSSV description:
https://alchetron.com/Cacao-swollen-shoot-virus-2002940-W
CRVV identification:
https://doi.org/10.1186/s12985-017-0866-6
CRVBV identification:
https://doi.org/10.1094/PDIS-09-18-1561-RE
Virus taxonomy and current _Badnavirus_ species list via:
https://talk.ictvonline.org/taxonomy/
Pests of cocoa including CSSV vectors:
http://www.dropdata.net/thamesvalleycocoa/Colin%20Campbell.pdf
Information on mealy bugs:
http://mrec.ifas.ufl.edu/LSO/Mealybugs.htm (with pictures)
- Mod.DHA]