Activity Title: Integrated management of potato bacterial wilt (Ralstonia solanacearum)

Goal: Contribute to reduce economic losses caused by potato bacterial wilt (BW) while improving sustainable potato production and crop competitiveness.

Purpose: To develop, test and implement in collaboration with NARS and with farmers’ participation sound IDM strategies through a better understanding of the disease epidemiology and the application and efficient use of highly sensitive detection techniques, cultural control practices, tolerant varieties and biological control agents.

Expected Outputs:

• Sensitive, reliable and low-costly serological techniques available for research on BW and potato seed quality testing and used by NARS.
• Increased knowledge on BW epidemiology.
• Innovative management options to improve soil health and control BW.
• Selected advanced potato clones with good and durable levels of resistance or tolerance to bacterial wilt and with other desirable traits available to NARS.
• New sources of high levels of resistance to BW identified in wild species of potato and mechanisms determined.
• Seed biological treatments available to control BW in Peru and methodologies transferred to selected NARS.
• Increased amount of self-produced healthy seed available to resource-poor farmers.
• Learning resources available for researchers, extension workers and farmers.

Brief Activity Description:

Bacterial wilt is a quarantine disease that is considered the main constraint to lowland tomato production and the second most important potato disease after late blight in mid-elevation highland areas. The pathogen that causes bacterial wilt called Ralstonia solanacearum affects over 200 species, especially tropical and subtropical crops families, the most susceptible crops being potato, tomato, tobacco, eggplant, pepper, ginger and groundnut. The disease occurs in about 45 countries in the Southern hemisphere and can destroy a harvest in its totality. Hardest hits are in China, Kenya, Uganda, Indonesia, Bangladesh, Bolivia and Peru. Moreover, the impact of the disease is not only on farmers’ income and food security but extends into environmental and social aspects influencing choice of land use and crop. Being a quarantine disease, presence of BW in seed and ware potatoes often limits market access for small farmers.

Unfortunately, there is no chemical known to combat bacterial wilt nor they are highly resistant varieties available. Thus only an integrated disease management approach can lead to significant reduction, or even eradication of BW. This involves mainly the planting of healthy seed in clean soil in rotation with non-susceptible crops as well as the application of various sanitation and cultivation practices to minimize pathogen dissemination.

The last five years at CIP, the scope for improving IDM of BW has been greatly enhanced through (1) the development at CIP of sensitive and specific serological detection kits to monitor R. solanacearum in seed tubers, water and soil, (2) the availability of CIP’s new potato clones moderately resistant or tolerant to BW, and (3) promising effective biological control using antagonistic bacterial endophytes for seed treatment.

The project aims at:

• Developing sensitive, reliable and user-friendly serological techniques for the detection of Ralstonia solanacearum in tubers (latent infection), soil and water and promoting their use worldwide. Actually these techniques are used in 14 countries worldwide.
• Developing and validating a new method for seed testing for BW latent infection in potato stems before harvest instead of tuber detection test in Peru, Kenya and Cameroon.
• Increasing knowledge about BW epidemiology, especially means of spread and survival of R. solanacearum in soil and determining soil abiotic factors that affect pathogen survival.
• Determining the effect of soil fertility management practices on BW control and on host plant resistance in the Andes and in Sub-Saharan Africa.
• Selecting BW-tolerant advanced potato clones and evaluating stability of resistance to BW while assessing their usefulness in BW-IDM with participation of farmers in Peru and Bolivia.
• Characterizing promising sources of high levels of resistance to both wilt and tuber infection in wild species of potato and study mechanisms of resistance .
• Developing biological formulations based on antagonistic endophytic bacteria for seed treatments to control BW in Peru and transferring methodologies to selected NARS in the Andes and in Sub-Saharan Africa.
• Evaluating options for BW management with farmers’ participation to improve self-sustained BW-free seed production in Sub-Saharan Africa, including a plant indexing system based on positive selection, spot soil treatments to enhance effectiveness of rouging, use of high-value rotation crops with a high capacity to reduce R. solanacearum soil population levels.
• Producing training materials for a wide range of stakeholders.

Agroecozone(s)/Location(s): Potato growing areas in v alleys and mid-elevated hillsides of the Andes (mainly Peru and Bolivia) and Sub-Saharan Africa (mainly Kenya, Uganda) with possible spill-over in selected countries in Asia (China, Indonesia, Myanmar, Philippines).

Partners:

1. Fundación para la Promoción e Investigación de Productos Andinos (PROINPA), Cochabamba, Bolivia; contact: Oscar Barea ( obarea@proinpa.org )
2. Servicio Nacional de Sanidad Agraria (SENASA), Peru ; contact: Dr. Elsa Carbonell Torres (Director) ( ecarbonell@senasa.gob.pe)
3. PRAPACE network (Programme Régional d’Amélioration de la Pomme de Terre et de la Patate douce en Afrique Centrale et de l’Est), Kabale, Uganda; Contact: Dr. Berga Lemaga (b.lemaga@cgiar.org)
4. Kenya Agricultural Research Institute (KARI), Nairobi, Kenya; Contact: Dr. Kinyua Z. Murimi ( z.kinyua@scientist.com )
5. National Agricultural Research Organisation (NARO), Kabale, Uganda; Contact: Dr. William W. Wagoire (wwagoire@infocom.co.ug)
6. Institute of Agricultural Research for Development (IRAD), South West Province, Cameroon; Contact: Leke Walter Nkeabeng (lekwat@yahoo.com)

Potential Impact(s) (Benificiary/ies): Beneficiaries of the project are potato farmers in mid-elevation regions of Peru, Bolivia, Kenya and Uganda. Intermediate users (secondary beneficiaries) are NARS, NGOs, and farmers’ associations that are involved in potato production and research that whose capacity will be strengthened or built from collaborative research and CIP’s training and backstopping; and especially national potato seed programs and seed certification agencies worldwide that will benefit from the distribution of CIP’s BW detection kits for seed testing.

The development of sound and economically rational set of IPM recommendations and increased farmers’ knowledge on disease epidemiology and control will contribute to improve farmers’ livelihoods, food security and income.

Contact person: Dr. Sylvie Priou (s.priou@cgiar.org); Plant pathologist, Bacteriologist; International Potato Center, Integrated Crop Management Division, Apartado 1558, Lima 12, Peru; Tel: +51 1 349 6017 ext 3070; Fax: +51 1 3175326;

Website: http://www.cipotato.org/potato/Pests_Disease/BacterialWilt/wilt.htm

Regional team:

Paul Demo (p.demo@cgiar.org) Seed specialist ; Peter Gildemacher (p.gildemacher@cgiar.org) Agronomist and Extension specialist; International Potato Center, P.O. Box 25171, Nairobi 00603, Kenya.

Main countries in CIP regions: Latin America and the Caribbean (LAC): Peru, Bolivia; Sub-Saharan Africa (SSA): Kenya, Ethiopia, Uganda; East and South East Asia and the Pacific (ESEAP): China, Indonesia, Vietnam; South and West Asia (SWA): Bangladesh, Nepal; CIP-HQ: CIP Headquarters, Peru