BANANA XANTHOMONAS WILT RESEARCH AT IITA

International Institute of Tropical Agriculture – Institut international d’agriculture tropicale – www.iita.org

Fen Beed, Ranajit Bandyopadhyay, Leena Tripathi, Jaindra Tripathi,

Komi Fiaboe, DJ Kim, Lava Kumar, Hein Bouwmeester, Muris Korkaric,

Valentine Nakato, Idd Rathamani, Piet van Asten, Maina Mwangi,

Steffen Abele, Jim Lorenzen

BANANA XANTHOMONAS WILT

RESEARCH AT IITA


• Diagnostics

• Disease surveillance

• Epidemiology

• Disease management

• Host plant resistance

Key activities


Field Diagnostics


Increase awareness

• To farmers?

What do I do?


Increase awareness to farmers of disease symptoms

and methods of control

runyankole

luganda


Mobile plant clinics

• direct help to growers

• surveillance of common and emerging diseases

• gathers demand for control technologies

• determines impact of control technologies

Field


Mobile plant clinics

Monitoring of common and emerging diseases and efficacy of control methods


Disease surveillance: IITA / NARO / Grameen

• Pilot disease surveillance study using SMS phone technology and community knowledge workers for BXW and BBTD

• Provide 2 way communication between science (diagnosis and control) and practice (grower’s observations and needs)

• Collate survey data (incidence and surveillance) for use by government for contingency planning to control diseases and safeguard trade

• To be out-scaled to increased number of districts and to cover all banana diseases (and hopefully for other crops towards providing a bidirectional extension service operated by e.g. NAADS)


Selective CCA Non-selective YPGA

Semi-selective media

Diagnostics: Semi-selective media

Selective YTS-CC

Mwangi et al. 2007

Tripathi et al. 2007


Molecular Diagnostics

• PCR detection of Xanthomonas campestris pv. musacearum in banana.

– Specific and sensitive primers

• PCR was used to monitor the movement of Xcm along banana pseudostem of a mother plant and its associated suckers.

Adikini et al. 2008

Adikini 2009, Master Thesis


Field to lab samples for diagnostics

• Sample collection

• FTA

• 2 minute extraction

• PhytoPass sticks

• Silica gel


Banana

Xanthomonas Wilt

in Kagera district,

Tanzania


Status of BXW

• Survey of BXW incidence - C3P project

• Developing GIS based tool for forecasting disease spread patterns, diagnosing epidemic phase and response framework guide

• C3P data presented as GIS output to predict impact of BXW on risk to food security and income generation

Uganda:

annual losses of 70 - 200

million US $

2-3 % of GDP

Burundi and Rwanda:

predicted 100 million US $

Uganda:

annual losses of 70 - 200

million US $

2-3 % of GDP

Burundi and Rwanda:

predicted 100 million US $


Main insects involved: Honey bee, stingless bees, wasps, drosophilids,

Chloropids (internally and externally)

Inoculum Source: bunch (ooze, nectar, sap, fruits)

Transmission: male bud and female inflorescence

Understanding BXW transmission for appropriate management

Distance: transmission of low inoculum quantities at

250m with only 0.4% diseased plants

Bee Propolis: Presence of bacteria and chemical

compound against Xcm

Symptom due to insects

and small birds

Drosophilids on sick

fingers

Honey Bees Wasps Stingless bees


Understanding BXW transmission for appropriate management

Alternative crops: flowering of palm trees affects bees’ presence/absence

Escaping factors: Nectar presence, quantity/quality; bract and flower

persistence

Altitude: No differences found in insect composition and abundance between

1000masl and 2000masl in DRC

Latent inoculation: banana can successfully grow to maturity when only

relatively low inoculum is transmitted and also through vertical

transmission

Coloration: virulent but orange Xcm colonies are obtained from latent cases

Field recovery: sick fields can be recovered if new infections are avoided

Recovering Field in DRC


IITA’s contribution to NARO led ASARECA project with

collaborators from Kenya and DRC

• Generate knowledge on wilt escape trait in relation to cultivars, seasonality and agroecology

• GIS based tool for forecasting disease spread patterns, diagnosing epidemic phase and response framework guide

• Developing improved cost effective tools for lab and field diagnosis of BXW

• Variability of Xanthomonas campetsris pv. musacearum

• Fallow period before replanting in BXW infested field

• Assess and manage risk of cross border BXW spread through trade

• Improving disinfecting technologies for pruning tools


Unpared corm Pared corm

have wounds,

are more suscept

Corm cured

for 2-3 days

after paring is

less susceptible

TC plants

No root injuries

Top soil

avoid

Subsoil

Less Xcm

Adjustments in planting practices can help

to avoid effect of Xcm in residues and soil

Technologies to support replanting

Mwangi et al. 2007


Effect of Potassium Nutrition on BXW

• Increased potassium availability for banana reduced disease incidence.

c d e

f g h i j

ba

BXW symptoms on FHIA 17 grown on 0.1K

(a), 0.5K (b), 1K (c) and 2K (d) and on

Kayinja grown on 0.1K (f), 0.5K (g), 1K (h)

and 2K (i). Controls (e) and (j) were

inoculated with sterile distilled water.

Atim et al. 2008

Use of potassium rich mulch

are recommended for testing

in field conditions


Germplasm Screening

• Screening of germplasm for resistance to BXW

started in Uganda in 2003

• No resistance varieties


Rapid Technique for Screening Banana

Cultivars for Resistance to Xanthomonas Wilt

• An in vitro screening method was developed using small tissue culture grown plantlets.

• Significant differences was observed in susceptibility among the various banana cultivars.

• No significant difference in pathogenicity was observed between the pathogen isolates.



Characterization of diversity of Xcm

• Genetic homogeneity among Ugandan

isolates of Xanthomonas campestris

pv. musacearum revealed by RAPD

analysis.

• No significant difference in

pathogenicity.

Odipio 2008, M.Sc. Thesis

Odipio et al. 2009


Development of BXW resistant varieties

• PFLP (plant ferredoxin-like protein) or

HRAP (HR assisting protein) from

sweet pepper.

– Collaboration with NARO & AATF

– Licence/FTO for genes

– Hundred of lines generated

– Molecular analysis

• PCR & Southern blotting

• RT-PCR & Northern blotting

– Promising results under lab. conditions

– Planning for CFT


Namukwaya et al. 2008

R4D Review 2008


CONCLUSIONS

• The recommended measures for BXW management involve a mixture

of approaches combining exclusion, eradication, host resistance, and

protection.

• Although much of the emphasis on BXW has focused on

management options based on information on other bacterial wilt

diseases, more basic and strategic information on the pathogen is

required.

• Some countries such as Uganda and Tanzania have achieved

remarkable success in containing the impact of the disease through a

mix of various management approaches.

• The development of disease resistant banana cultivars remains a high

priority because farmers are reluctant to employ labor-intensive

disease control measures.


Acknowledgements

• Partners/Collaborators

– NARO- Uganda

– KARI- Kenya

– ARD- Tanzania

– INERA- DR Congo

– IRAZ/ISABU-

Burundi

– ISAR- Rwanda

– Makerere University

– Academia Sinica,

Taiwan

– Bioversity

– FAO

– ARIs

– AATF

• Funding support

– Gatsby Charitable

Foundation

– CRS

– USAID

– BecA/CIDA

– DFID

– AATF

– CIALCA

– IITA


IITA’s contribution to NARO led ASARECA project with

collaborators from Kenya and DRC

• Generate knowledge on wilt escape trait in relation to cultivars, seasonality and agroecology

• GIS based tool for forecasting disease spread patterns, diagnosing epidemic phase and response framework guide

• Developing improved cost effective tools for lab and field diagnosis of BXW

• Variability of Xanthomonas campetsris pv. musacearum

• Fallow period before replanting in BXW infested field

• Assess and manage risk of cross border BXW spread through trade

• Improving disinfecting technologies for pruning tools

Dynamic reporting – use of updated PRA?


• To extension,

researchers

& policy makers


A PRA is a dynamic document that states current knowledge

and how this relates to risk

A PRA poses key questions on extension, research and policy

needs

A PRA provides the framework

for contingency planning


A PRA provides an assessment of:

• efficacy of control options,

varieties,

husbandry practices

• gaps in knowledge and the

uncertainty these presents

• risk of entry, establishment and

spread across PRA area

• consequence, in terms of

economics,

environmental and social impact


Questions, comments, discussion?

BANANA XANTHOMONAS WILT RESEARCH AT IITA

Technology

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