Acknowledgements
6.1. Introduction
Coffee is a major export crop in Africa and accounts for the bulk of the export earnings of most economies in the Eastern and Central Africa (ECA) regions.
It is also important because of its contribution to farm income, employment and food security. The crop is a major source of livelihood particularly for small-scale producers. Coffee is a leading export sector in Uganda’s economy, accounting for over US$100 million in export sales in the 2000/2001 market year (GoU, 2001). In Kenya, coffee ranks fourth after horticulture, tea and tourism, accounting for 10% of the total export earnings (Karanja and Nyoro, 2002). Similarly, the commodity is Tanzania’s largest export crop, contribut- ing approximately US$115 million to export earnings and provides employ- ment to over 400,000 families (Baffes, 2003). In Ethiopia, coffee contributes around 50% to the country’s foreign exchange earnings and about 10% of the gross domestic product. More than 25% of the population of Ethiopia, which represents 15 million people, are dependent on coffee for their livelihoods, including 8 million people directly involved in coffee cultivation and 7 mil- lion in the processing, trading, transport and financial sectors (Beintema and Solomon, 2003; Oxfam, 2002; Charveriat, 2001). In the Democratic Republic of Congo (DRC), coffee is the number three export after copper and cobalt, and it
represents approximately 9% of the total value of DRC exports and almost 60%
to 65% of the total value for the whole of exports of the agricultural produce (Banque Centrale du Congo, 2005). Growth in coffee production and income has been one of the main engines for the development of coffee-producing areas. Thus, coffee plays a significant role in the national economies and the livelihood of the rural poor in the subregion.
Coffee production, productivity, quality and earnings are under threat from coffee wilt disease (CWD). Incidence and severity of CWD are highest in Uganda and lowest in Tanzania (Table 6.1). In Tanzania, the disease was only found in the Kagera region, which borders Uganda.
CWD is observed on robusta coffee only in DRC, Tanzania and Uganda;
whereas in Ethiopia, it was observed on arabica coffee only. This finding sug- gests that the diseases found in the two coffee types, which are also separated geographically, are genetically distinct (Oduor et al., 2003). Following the re- emergence of CWD, farmers have experienced changes in their livelihoods and resource endowments and have adopted various coping strategies as a result of the disease. This chapter examines some of the changes that have occurred in respect to coffee since the re-emergence of CWD as farmers try to deal with the problem in DRC, Ethiopia, Tanzania and Uganda and draws conclusions and recommendations aimed at improving coffee production through containment of the disease. The changes analysed include (i) the im- portance of coffee as a source of income, (ii) coffee production, (iii) input use in coffee, (iv) liquidation of assets, (v) coping strategies and (vi) household expenditure.
Different sampling approaches were used in different countries to iden- tify the households to provide the requisite data. The sampling approach used depended on the distribution of CWD in the country, with purposive sampling being used where incidence of the disease was relatively low or fo- cused in certain areas of the country and random sampling where CWD was widespread and severe. In Tanzania, CWD was found in the Kagera region only, and cluster sampling was used in villages known to have CWD, and these were identified through key informants; purposive sampling was used to target 99 affected farms. In Uganda, a multistage sampling procedure was followed in which 21 robusta-coffee-growing districts affected by CWD were targeted; subcounties, parishes and villages were subsequently selected ran- domly. Three farmers were then selected from each village. A total of 356 households were interviewed. In Ethiopia, the socio-economic survey was
Table 6.1. Incidence and severity of CWD in countries in the ECA region.
Incidence (%) Severity (%)
DRC 90.0 40.5
Ethiopia 27.9 3.0
Tanzania 2.2 0.7
Uganda 90.3 44.5
Plate 1. Coffee field attacked by CWD as shown by stumps of dead trees. (Photograph courtesy of G. Hakiza.)
Plate 2. (a) Healthy coffee field in 1993. (b) The same field in 1998. (Photograph courtesy of G. Hakiza.)
2a
2b
Plate 3. Robusta plant affected by CWD in Uganda. (Photograph courtesy of S. Olal.) Plate 4. (a and b) Arabica coffee trees with complete wilt symptoms. (Photographs courtesy of A. Girma.)
4a 4b
Plate 5. Veinal necrosis, caused by coffee wilt disease (Gibberella xylarioides), clearly visible on the underside of a coffee leaf. (Photograph © M. Rutherford.)
Plate 6. Wounds (arrows), originating from slashing during weed control, at the base of a coffee stem. (Photograph courtesy of N. Phiri.)
Plate 7. Stromatic fruiting bodies (perithecia and ascospores of Gibberella xylarioides in the bark of dead Arabica coffee tree. (Photograph courtesy of A. Girma.)
Plate 8. Characteristic blue-black colouration under the coffee bark when an infected stem is scraped with a knife. (Photograph courtesy of N. Phiri.)
7 8
Plate 9. Perithecioide ascomata (‘perithecia’) produced by the coffee wilt pathogen, Gibberella xylarioides, in cracks of the tree bark. (Photograph © J. Flood.)
Plate 10. Diagrammatic representation of asci (left) and the typically curved conidia (right) of the coffee wilt pathogen, Gibberella xylarioides. Asci contain eight two-celled ascospores.
Illustration from Booth, C. and Waterston, W.M. 1964. CMI Descriptions of Plant pathogenic Fungi and Bacteria No. 24, CABI, Wallingford.
Plate 11. Conidia of Gibberella xylarioides on Spezieller Nährstoffarmer Agar (SNA) medium. (Photograph © P. Lepoint and H. Maraite.)
Plate 12. Asci of Gibberella xylarioides, the coffee wilt pathogen, containing two celled ascospores (arrowed). (Photograph © J. Flood.)
Plate 13. Failure to produce orange pigmentation, a characteristic used to rapidly
differentiate biological species BS 1 from other representatives of the G. xylarioides complex.
In this case, MAT-1 C. canephora-associated (BS 2, orange colonies) mating type tester strains were confronted with a MAT-2 C. arabica-associated G. xylarioides sensu lato strain (BS 1, white colony) on carrot agar. Incompatibility between the two BS is denoted by the absence of perithecia or protoperithecia along the confrontation zones. (Photograph © P.
Lepoint and H. Maraite.)
Plate 14. Production of perithecia along confrontation zones of G. xylarioides sensu lato strains of opposite mating type and of the same biological species (BS). (Photograph © P. Lepoint and H. Maraite.)
11
12
13 14
Plate 15. Purple black G. xylarioides sensu lato perithecia producing an orange cirrhus of ascospores on carrot agar medium when C. canephora associated strains of opposite mating type are crossed. (Photograph © P. Lepoint and H. Maraite.)
Plate 16. Graphical representation of the spatial and temporal development of coffee wilt disease on coffee trees on a farm in Mayuge, Uganda. This depicts the point, during a 17 month study involving ten assessments, at which external disease symptoms were first observed. Points where trees were missing at the outset of monitoring, dead trees and trees that did not develop symptoms throughout the study are denoted by white, black and grey spots respectively. Trees that developed symptoms in the earlier, intermediate and latter stages of the study are denoted by red, orange and yellow spots respectively, the numbers denoting the actual assessment point (1-10) at which symptoms were first observed.
(Illustration courtesy of M. Rutherford.)
16
Plate 17. Host specificity of Gibberella xylarioides isolates collected from Coffea arabica and C. canephora on seedlings of the respective host species. (Photograph courtesy of A. Girma.) Plate 18. Host specificity of Gibberella xylarioides isolates from Coffea arabica (G3P22), C. canephora (CAB003, TZ009) and C. excelsa (DSMZ 62457) on seedlings of C. arabica (cv. SL28) in growth room. (Photograph courtesy of A. Girma.)
Plate 19. Specificity of Gibberella xylarioides isolate DSMZ62457 (an historical Excelsa strain), G3P22 (Arabica strain) and CAB003 (Canephora strain) on Catimor seedlings (1570) in growth room. (Photograph courtesy of A.Girma.)
18
19
Plate 20. The characteristic unilateral wilting symptoms caused by the historical strain DSMZ 62457 on C. liberica seedlings. (Photograph courtesy of A. Girma.)
Plate 21. Gibberella xylarioides -Coffea canephora interaction at cellular level (cross section of a 9-month old infected seedling (Photograph courtesy of D. Bieysse.)
Plate 22. Gibberella xylarioides-Coffea canephora interactions at cellular levels (arrow hyphal colonization of vascular tissues of 18-month old seedlings 45 days after inoculation.
(Photograph courtesy of D. Bieysse.)
21
22
Plate 23. ScreeningCoffea arabica collections by seedling inoculation test in the green house in Ethiopia (Jimma). (Photograph courtesy of A.Girma.)
Plate 24. Coffea arabica seedlings re-inoculated to verify the resistance in the screen house.
(Photograph courtesy of A.Girma.)
Plate 25. C. canephora seedlings that survived (resistant) CWD infection after the first bout of inoculation. Left foreground, susceptible plants: right foreground, survivors. (Photograph courtesy of P. Musoli.)
24
25
Plate 26. Diversity of Ugandan C. canephora and other diversity groups. (Illustration cour- tesy of P. Musoli.)
Plate 27. Eracta and nganda C. canephora trees. (Photograph courtesy of P. Musoli.)
27
Plate 28. Uprooting and burning is the most effective eradication strategy for CWD infected trees. (Photograph courtesy of N. Phiri.)
Plate 29. FFS farmers practicing pruning technique. (Photograph courtesy of N. Phiri.) Plate 30. A coffee farm mulched with dry grass which suppressed weeds. (Photograph courtesy of N. Phiri.)
Plate 31. A coffee farm planted to Desmodium intotum which suppressed weeds.
(Photograph courtesy of N. Phiri.)
30
31
Plate 32. (a and b) TaCRI team receiving training at Kituza. (Photograph courtesy of H. Mutenyo.)
Plate 33. (a and b) Spreading CWD technologies through participatory approach.
Plate 34. Farmers carrying out agro-ecosystem observation and analysis in small groups.
Plate 35. Media interviews with (a) Ethiopian researchers, (b) farmers and (c) CABI scientists.
33a 33b
34 35a
35b 35c
conducted in four regions confirmed to have CWD, namely, the Southern Nations Nationality Peoples, Oromiya, Gambella and Amhara. Households with a CWD severity of at least 10% were randomly selected from each of the regions. A total of 137 households were interviewed in Ethiopia. In DRC, the survey was conducted in North Kivu and eastern provinces where a total of 436 households were randomly selected and interviewed.
Structured questionnaires were used to collect data from all the selected households in all the countries between March 2002 and January 2003. Data collected included household characteristics, farm characteristics, farmers’
perceptions of CWD, awareness and ability to identify the disease, severity of CWD and its progression on farms, coping strategies by farmers, income changes, input use, asset portfolio and changes in household expenditure.
Data collected were analysed using descriptive statistics, regression analyses and chi-square tests to establish relationships. Analysis was conducted us- ing the Statistical Package for Social Scientists. Information from other minor studies on the disease carried out in individual countries has also been incor- porated for comparison purposes and to enrich the chapter.