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Development of a long-term strategy based on genetic resistance and agro-ecological approaches against Coffee Wilt Disease in Africa

Funders

European Commission (INCO-DEV)

Partners

Centre de coopération Internationale en Recherche Agronomique pour le développement (CIRAD) (Co-ordinating Agency), CABI Bioscience (UKC), Université catholique de Louvain (UCL), National Agricultural Research Organisation (NARO) (Uganda), Coffee Research Institute (CORI) (Uganda), Faculté des Sciences Agronomiques (FACAGRO) de l'Université de Kinshasa (UNIKIN) (Democratic Republic of Congo)

Project Description


Plantation decimated by Coffee Wilt Disease

Problem/Issue. Eastern and Central Africa is witnessing the re-emergence and spread of a major coffee disease, coffee wilt, also known as tracheomycosis. This disease was first observed in 1927 in the Central African Republic on Coffea excelsa and the pathogen identified in the Democratic Republic of Congo (DRC, formerly Zaire) in 1948. The disease was successfully controlled in the 1940s and 1950s but within the last six years its incidence has increased considerably. It mainly affects Robusta Coffee (Coffea canephora) in DRC, Uganda and Tanzania, and is currently the major biotic constraint of Robusta growing in these countries, as it used to be in central and West Africa in the 1950's. This disease disappeared after replanting with tolerant varieties, but they now appear to be susceptible. In that context, and taking into account the subsistence systems prevailing in Africa, durable genetic resistance is believed to be the most suitable control method.

CABI Bioscience carried out surveys of the status of coffee wilt in DRC and Uganda in 1996/97. Coffee is Uganda's premier export, accounting for up to 55% of the countries foreign exchange but 70% of the coffee growing areas are now affected by coffee wilt and production has declined from 4.4 million bags in 1996-97 to 3.6 million bags in 1997-98 (latest data available). The coffee industry in Uganda employs more than 2.5 million people and it has been estimated that coffee households are facing a reduction in third of their income due to this disease. Coffee wilt continues to cause severe damage to robusta coffee in DRC. The disease has also been found on the borders of Rwanda and Tanzania. If left unchecked, it poses a major threat to coffee production throughout East Africa.

The biology of the causal agent (Gibberella xylarioides) is poorly understood and an international workshop was held in Uganda in 1997, leading to the development of a regional programme for research on the control of Tracheomycosis, involving DRC, Ethiopia, Rwanda, Tanzania and Uganda.

This project forms part of that Regional Coffee Wilt Programme which was further outlined at a workshop in February 2001 (PDF file). The multi-funded status of the Regional Coffee Wilt Programme (see also the CFC funded Coffee Wilt Project) was discussed and it was agreed that the programme be divided into separately funded but inter-linked complementary projects.

Measures to Date. It has been difficult to provide rational control solutions to the disease as detailed knowledge of the epidemiology and variability of the pathogen is not available. Even the basic biology of the fungus such as its survival in soil, or in seed, is unknown. Current recommendations for control of the disease come from previous studies, and include:

  • Phytosanitation practices to limit the source of inoculum, assumed to be infected trees, which involves uprooting and burning them on the spot;
  • There are no biological control methods available, and chemical control is likely to be ineffective due to the vascular nature of the pathogen;
  • Several authors have reported varietal differences in resistance to the pathogen and suggest the use of resistant varieties as a means of control. However, this requires further investigation because the resistant varieties developed in one region may be ineffective in others.

Project Activities. The general objective of this project is to develop a global strategy for durable resistance in agrosystems prevailing in Africa. More specifically, the project aims at securing a better knowledge of the host/pathogen relation (resistance) and of the disease itself, both in field and lab conditions. This project brings together internationally recognised scientists from different disciplines and from various institutions. Specific Work Packages are to be undertaken:

  1. Host/pathogen relation: Elaborate reproducible screening tests to understand the histological mechanisms of tolerance or resistance.
  2. Breeding: Identify sources of resistance to understand its inheritance in order to define a breeding strategy for durable resistance.
  3. The pathogen: Collect and identify isolates from various zones, and try to get a clear picture of its cycle and of its variability in view of understanding its evolution especially through the sexed phase. Identify and purify toxins.
  4. The disease: Understand the reasons of new outbreaks, and the way it spreads over coffee regions.

Achievements So Far

An initial Project workshop took place between March 3rd and 8th 2002, in Kampala, Uganda. CABI Bioscience conducted short identification training sessions, and workplans for the project were finalised and agreed amongst project collaborators.

What Next

Project activities will start during the course of 2002.

Dr. Julie Flood (CABI Bioscience Co-ordinator) j.flood@cabi.org

Start date: December 2001

End date: 2005

 
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Contact CABI Commodities:
CABI Commodities Coffee Co-ordinator - Dr. Peter Baker - p.baker@cabi.org
CABI Commodities Cocoa Co-ordinator - Dr. Keith Holmes - k.holmes@cabi.org
CABI Commodities Project Administrator - cabi-commodities@cabi.org