ProMED
http://www.promedmail.org

Source: The Guardian (Tanzania) [summ. Mod.DHA, edited]
https://www.ippmedia.com/the-guardian/business/read/new-ai-tech-to-help-farmers-in-fighting-banana-disease-2024-08-06-123200

The International Institute for Tropical Agriculture (IITA) has developed digital artificial intelligence facilities to help farmers detect banana bunchy top disease (BBTD). This was announced by IITA scientists at the current 31st Tanzania Agricultural International Exhibition.

The disease has so far destroyed a huge percentage of banana plantations across the country. Since it was reported for the first time in Tanzania [in 2021 - Mod.DHA; ProMED post 20211012.8699013], BBTD has spread to many regions.

IITA is working with the Ministry of Agriculture, the Tanzania Agricultural Research Institute and the Tanzania Plant Health and Pesticides Authority to disseminate knowledge and skills to farmers. Several different approaches to fight the disease are being used, including also control of the vector insects.

[Byline: Valentine Oforo]

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Communicated by:
ProMED

[_Banana bunchy top virus_ (BBTV) is the type member of the genus _Babuvirus_ (family Nanoviridae). It affects only _Musa_ species and hybrids. BBTV causes one of the most serious diseases of these crops with symptoms of chlorosis, stunting and death of the host plant. The virus is spreading in Africa, Australasia and the Pacific Islands.

BBTV is transmitted by the banana aphid _Pentalonia nigronervosa_ in a persistent manner. Infectious insects may be spread on plant material or by air currents. The virus is also spread with infected suckers but cannot be transmitted by mechanical means (such as cutting tools). Disease management is extremely difficult and may include vector control, removal of inoculum, use of clean planting material, as well as frequent scouting for new outbreaks. Eradication of established BBTV from a planting or natural cluster of plants is considered impossible; the only option is to kill off all plants in the group. Tolerant varieties can be used to enable some crop production in infected areas, but these cultivars may still support virus replication and thus serve as pathogen reservoirs.

There are 2 groups of BBTV isolates from different regions: the South Pacific group (including Australia, Egypt, Fiji, India, Tonga, Western Samoa and sub-Saharan Africa) and the Asian group (including Philippines, Taiwan, Viet Nam). The mean sequence difference between the 2 groups has been reported as approximately 10% (see link below). This is thought to suggest that the virus has spread after the initial movement of its hosts from the Indo-Malayan region, where edible _Musa_ species originated, to Africa and the Americas.

BBTV is closely related to _Abaca bunchy top virus_ (ABTV) reported from some areas of SE Asia (ProMED post 20191215.6842101). ABTV and BBTV cause the same disease symptoms in both banana and abaca (_M. textilis_).

In Africa, BBTV is thought to be present currently in around 16 countries (e.g., ProMED posts 20240515.8716522, 20211117.8699734). The virus is also endangering the diversity of banana varieties and landraces that are predominantly grown by farmers because they are well adapted to local conditions.

Pictures
Bunchy top symptoms on banana:
https://feww.files.wordpress.com/2009/08/infected_plant.jpg?w=468&h=311,
https://www.iucngisd.org/gisd/image/ecology/infected_fruits5.jpg and
http://callisto.ggsrv.com/imgsrv/FastFetch/UBER1/ZI-5YXF-2015-JAN00-IDSI-61-1
Bunchy top photo galleries:
https://www.ctahr.hawaii.edu/banana/leaves_bunchy.asp (whole plants),
https://www.ctahr.hawaii.edu/banana/morse_code.asp (leaves),
https://www.ctahr.hawaii.edu/banana/deformed_fruits.asp (fruits) and
https://www.ctahr.hawaii.edu/banana/closeup_photos.asp (banana aphids)

Links
Information on BBTV:
https://apps.lucidcentral.org/pppw_v10/text/web_full/entities/banana_bunchy_top_121.htm,
https://gd.eppo.int/taxon/BBTV00 (with distribution),
https://doi.org/10.1079/cabicompendium.8161 and
http://www.ctahr.hawaii.edu/banana/downloads/brochure1.pdf
BBTV description and genetic groups:
https://doi.org/10.1099/0022-1317-75-12-3541
First report of BBTV in Tanzania & East Africa:
https://doi.org/10.1094/PDIS-07-21-1387-PDN
ABTV description and characterisation:
https://doi.org/10.1007/s00705-007-1077-z
Information on genus _Babuvirus_:
https://viralzone.expasy.org/564
Virus taxonomy via:
https://ictv.global/taxonomy
Information on the banana aphid:
http://www.extento.hawaii.edu/kbase/crop/Type/pentalon.htm
BBTD Alliance:
https://www.iita.org/news-item/international-multi-stakeholder-alliance-continue-to-tackle-banana-bunchy-top-disease-in-africa/ and via
https://www.bbtvalliance.org/
IITA:
https://www.iita.org/
- Mod.DHA