Crop Genebank Knowledge Base

Health diagnosis

Health diagnosis and testing of banana genetic resources

Contributors to this page: Bioversity International, Belgium (Ines Van den Houwe); IITA, Nigeria (Dominique Dumet, Badara Gueye).

List of pests and diseases of quarantine importance for banana

The list below mentions some of the pests/diseases that were considered important worldwide, but many of them may or may not have relevance in specific countries. It also does not consider pests/diseases of limited relevance (e.g. only important in very few countries).

America has the greatest diversity of banana pests, followed by Africa and then Asia. Damage in Africa is often high due to the lack of natural predators of pests. Damage is greatest in the dry season or in dry areas with low or irregular rainfall.

The green mite (Mononychellus tanajoa) (America and Africa) and the mealybug (Phenococcus manihoti and P. Herreni) cause major damage in Africa.
Whiteflies (Aleurotrachelus socialis and A. aepim), hornworm (Erinnyis ello), stemborers (Chilomina clarkei), burrower bugs (Sternocoelus manihoti and Tropidozineus fulveolus), thrips (Frankliniella williamsi) and lacebugs (Vatiga manihoti, V. illudens and Amblydtira machalana) are a problem in America.
While scales (Aonidomytilus albus), termites and grasshoppers are widely reported.
Amongst the main banana diseases there are the complex of:
- Banana mosaic diseases (CMD) caused by the African banana mosaic virus (ACMV), the East African banana mosaic virus (EACMV) and by the South African banana mosaic virus (SACMV).
- The banana brown streak virus (CBSV) in Africa.
- In South America, the main viral diseases are caused by the banana common mosaic virus (CsCMV and CsXV) and by the banana frogskin virus (CFSV).
- Other diseases like banana bacterial blight (CBB) or those caused by fungi, like banana anthracnose and root rot, are important worldwide.

Additional information is available on this website in the section Safe Transfer of Germplasm (STOG).

Options for testing procedures

Recommended methods to detect the presence of each pest or disease.

Viruses

Any accession officially deposited in the genebank (regardless of its origin) should have a representative sample indexed for banana viruses.

There are three Virus Indexing Centres (VIC) - CIRAD in France, QDPI in Australia or PPRI in South Africa - recognized by Bioiversity, using standard protocols as described in the FAO/IPGRI Technical Guidelines for safe Movement of Germplasm for Banana (FAO/IPGRI 1996).

After the initiation phase, seven cultures should be produced from one selected culture derived from one single shoot tip (meristem).
Five cultures should then be regenerated into rooted plants that will be provided to one of the VICs and four plants should be tested.
The two remaining cultures remaining at the in vitro genebank should be used for further multiplication.
The plants should be cultured in a screen house for six months. At three months intervals, the plants should be visually examined for virus symptoms relevant in the genebank regions.
Indexing for Banana Bunchy Top Virus (BBTV), Cucumber Mosaic Virus (CMV) and Banana Bract Mosaic Virus (BBrMV) should be done by ELISA (Enzym-linked immunosorbent assay) or PCR.
For Banana Mild Virus (BanMMV) and Banana Streak Virus (BSV), PCR and immunosorbent electron microscopy should be used using a partially purified virus preparation and a mixture of polyclonal antisera.
Electron Microscopy is used to detect unidentified/uncharacterized virus (-like) particles.
If the tests indicate that the accession is infected with one or more viruses, the accession is categorized as ‘virus-positive’ and the accession should be subjected to virus therapy, if eradication methods are available.
If the test results for all replicate plants of an accession are negative, the accession can be categorized as ‘virus-negative’ and released for international distribution.

Fungi

Blotter test, agar test, washing test, direct visual inspection.

Bacteria

Seedling symptom test, dilution plating test.

Weeds

Direct visual inspection.

Insects

Direct visual inspection.

Nematodes

Direct visual inspection.

Testing intervals/seasons

Testing before the material is introduced into the genebank or to the field is important to reduce transfer of diseases or pests.

Virus

Test seedlings before transfer to the field for regeneration or during regeneration, and rogue infected material.

Fungi

Test plant propagules on entry to genebank and regularly thereafter.
Rogue infected material.

Bacteria

Test plant propagules on entry to genebank and regularly thereafter.
Rogue infected material.

Weeds, insects and nematodes

Test plant propagules on entry to genebank and regularly thereafter.
Rogue infected material.

Recording information during health diagnosis

The following information should be recorded for each health diagnosis step:

Site name and map/GPS reference.
Name of collaborator.
Field bank site name (a code to identify the site location).
Plot reference (the plot number at the field site).
Accession number; population identification.
Name of staff (name of staff recording the data).
Date of monitoring (date when data is collected).
Date of test (the date that the test was commenced).
Number of replications (the number of replicates in the test).
Size of the samples per replication /li>
Pre-treatments (pre-treatments used for the test).
Media (the media used for the test, e.g. for fungi).
Material (which plant part used).
Pathogen tested (name of pathogen tested).
Test method (method used).
Percentage of infection (% of plants or samples infected).

References and further reading

Diekmann M, Putter CAJ, editors. 1996. FAO/IPGRI Technical Guidelines for the Safe Movement of Germplasm. No.15. Musa spp. 2nd edition. Publisher: Food and Agriculture Organization of the United Nations, Rome; International Plant Genetic Resources Intstitute, Rome, Italy. 28 pp. Available here.

Helliot B, Panis B, Frison EA, De Clercq E, Swennen R, Lepoivre P, Neyts J. 2003. The acyclic nucleoside phosphonate analogues, adefovir, tenofovir and PMEDAP, efficiently eliminate banana streak virus from banana (Musa spp.). Antiviral Research (NLD), 59 (2):121-126. An abstract of this publication can be read here.

Van den Houwe I, Guns J, Swennen R. 1998. Bacterial contamination in Musa shoot tip cultures. International Symposium on Banana in the Subtropics. Acta Horticulturae 490:485-492. An abstract and purchase of the publication is available here.

Van den Houwe I, Panis B, 2000. In vitro conservation of banana: medium term storage and prospects for cryopreservation. Razdan MK, Cocking E, editors. Conservation of Plant Genetic Resources in vitro. Vol. 2. M/S Science Publishers, USA. pp. 225-257.

Van den Houwe I, Panis B, Arnaud E, Markham R, Swennen R. 2006. The management of banana (Musa spp.) genetic resources at the IPGRI/INIBAP gene bank: the conservation and documentation status. In: Segers H, Desmet P, Baus E, editors. Tropical biodiversity: science, data, conservation. Meeting: 3rd GBIF Science Symposium, Brussels, 18-19 April 2005. pp. 141-150. Available here. (8 MB)

Van den Houwe I, Swennen R. 2000. Characterization and control of bacterial contaminants in in vitro cultures of banana (Musa spp.). Meeting: International Symposium on Methods and Markers for Quality Assurance in Micropropagation. Acta Horticulturae
530:69-79. An abstract and purchase of the publication is available here.

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