Key banana pests and diseases and their mitigation in Africa. Eldad Karamura et al

Transcription

1 Key banana pests and diseases and their mitigation in Africa Eldad Karamura et al

2 Presentation outline Banana systems characteristics in Africa Key banana pests and disease in Africa Risks associated with key pests and diseases Mitigation strategies

3 Banana systems characteristics in Africa

4 Banana Production in Africa: Systems characteristics Region Year AAA-EAHB Africa 40,158,682 tonnes 39,653,941 tonnes Eastern Africa 22,073,329 tonnes 21,533,708 tonnes Middle Africa 6,288,916 tonnes 6,361,672 tonnes Cavendish Cavendish PLANTAINS Northern Africa 1,984,793 tonnes 1,993,270 tonnes Southern Africa 376,505 tonnes 399,021 tonnes Western Africa 9,435,139 tonnes 9,366,270 tonnes FAO production data, 2012

5 Systems characteristics cont d Main banana production systems in Africa 3% 17% 31% Plantains AAB East African highland bananas + ABB,AAB,AA Cavendish AAA 49% Gros Michel & other AA,AAA,AAB,ABB Lescot, 2010

6 Systems Characteristics cont d Banana in diets in Africa Ba n a n a d ie t s h are ( % ) N o d ata U ganda D R C on go K en ya R w an da B urun di Tanzania

7 Systems Characteristics cont d: Consumption in eastern and southern Africa 250 kg / capita / yr Source: FAOSTAT 7

8 Systems Characteristics cont d: Annual per capita plantain consumption in Nigeria and Cameroon (Kg) Cameroon South Nigeria Children Mothers Ref: Honfo FG, et al, 1996

9 Regional GDP Gains to 2015 from Growth in Selected Commodity Sub-Sectors Sectors (US$ million) Milk Oilseeds Cassava Sorghum_Millet Vegetable_Fruits Beef Maize Bananas Coffee_Tea Potatoes_Sweetpotatoes Rice Wheat_Barley Beans_Peas Poultry Sugar

10 Systems characteristics cont d Especially in eastern and west Africa, the banana systems are slow-changing and rural-based economies under stress due to population pressure/decreasing farm size; decreasing land fallow periods and production progressively unable to meet household needs. facing additional stresses, including climate change, characterized by increasing temperatures and greater rainfall variability; and changing social structures due to HIV-AIDS, rural-to-urban migration and declining returns from agriculture.

11 Systems characteristics Smallholder banana production as a system in Africa is built to a large extent on an informal seed system with minimum attention to quality. Informal seed systems account for 95-98% of the seed exchanges lacks a well organized seed system to subtend sustained production Planting material is the principle mechanism for disease transmission between farms and landscapes Banana stands in smallholder systems are perennial for certain production systems, spanning over 5>150 years Steady build up of pests and diseases, leading to productivity declines

12 Systems Characteristics cont d: Farm sizes Percentage >0-2 >2-4 >4-6 >6-8 >8-10 >10-15 >15-20 >20-40 Acres Uganda Tanzania Kenya Low input Low output systems

13 Systems Characteristics Small; low input subsistence/semi-commercial systems

14 Key banana pests and disease in Africa

15 Biotic stresses range from viruses, fungi, bacteria and nematodes to insects Black leaf streak BXW symptoms Foc Wilt Nematodes Weevil infestation Banana Steak Virus? BBTV

16 Key pests and diseases cont d In general highlands and sub-tropical regions have very less pest and disease pressure resulting into better productivity than in the equatorial humid lowlands; The equatorial belt has the highest pest and disease intensity which progressively reduces towards the subtropical regions; There is a need to systematically rank banana pests and diseases in Africa in order to guide research investment.

17 Suggested Ranking Criteria for pests and diseases in Africa 1. Number of countries affected. (Reference Gowen, 1995; Jones 2000; Blomme, et al, 2012) 2. Number of banana genotypes (Stover, 2000; Jones 2000; Blomme, 2012) 3. Yield loss attributed to each pest or disease ( Jones, 2000; Gold et al, 2001, ) 4. Ease of control (Robinson, 1996; Gowen, 1995; Jones 2000) 5. Ease of eradication or probability of permanent control 6. Estimated costs of control (High, medium, low?) 7. Short-term impact on communities (high, medium, low?) 8. Long-term impact on communities (high, medium, low?)

18 Key banana pests and diseases have not changed over the last decade Staver (2000) Viljoen (2010) Blomme et al 2012 Black leaf spots (M.fijiensis & Cladosporium) Xanthomonas Banana Weevil Nematode Fusarium wilt Nematodes Weevil Black leaf streak BBTD Fusarium Nematodes BSV Viruses Banana Weevil Mycosphaerella leaf spots Viruses Viruses Xanthomonas wilt Fusarium

19 Risks associated with key pests and diseases

20 Risk 1. Potential for rapid dispersal by natural means Some diseases are spread by vectors over short and long distances accidentally and/or intentionally (BXW BBTD, BSV, etc) Most are moved in planting material in the informal seed systems (BBTV, BSV, BBrMV, CMV, BMMV, weevils, nematodes, Foc, BXW); ubiquitous plantings of bananas provide reservoirs of pests/diseases making it difficult to control Weak and/or non-existent quarantine services linked to lack of surveillance and limited information exchange within and between countries and regions. Limited capacity for efficient/effective pest and disease detection in support of quarantine 20

21 Risk 2. Extensive yield losses threatening food security A major yield gap exists especially in tropical Africa Year Region Africa tonnes/ha tonnes/ha Eastern Africa tonnes/ha tonnes/ha Middle Africa tonnes/ha tonnes/ha Northern Africa tonnes/ha tonnes/ha Southern Africa tonnes/ha tonnes/ha Western Africa tonnes/ha tonnes/ha FAO production data, 2012

22 Risk 2. Extensive yield losses cont d 1. Yield is a product of complex interactions between, the genotype, soil fertility, pests and diseases; 2. Methods are very variable, making comparisons difficult. 3. For some regions/countries, studies on yields attributed to pests and diseases are very limited 4. Nevertheless, pests and diseases probably contribute a significant proportion of the yield gap;

23 Risk 3. Environment damage Use of chemical control is still limited in smallholder systems but may increase with changing farming objectives; Wide spread adoption of resistant varieties recommended to manage pests and diseases; but this may lead to monoculture and loss of diversity; Extensive rouging may lead to loss of associated biodiversity.

24 BXW management effects on environment Parameter Macrofauna Mean number/trap/sample Abundance Control (0 % rouged) 100% Rouged 100 % rouged Hymenoptera (ants) Isoptera Coleoptera Orthoptera Araneida Others Control (0% rouged) Diversity Number of orders 24 15

25 Mitigation

26 MITIGATION STRATEGIES RECOMMENDED STRATEGY 1. Host plant resistance by convectional 2. Host plant resistance by biotechnology 3. Clean planting material linked to formal seed systems 4. Cultural controls PRODUCTION SYSTEMS IN AFRICA EAHB & plantain EAHB & plantain EAHB, Plantain, cavendish EAHB & Plantain in small holder systems All systems targeting 5. Biological control weevils and FoC 6. IPDM All systems REMARKS REFERENCE IITA in Nigeria for plantains NARO/IITA in Uganda for EAHB; several varieties released in both regions IITA(NARO) has successfully transferred the sweet pepper gene against BXW; plants in CFT. More work in progress with cystatin genes against weevil borer in EAHB South Africa, Ivory cost, Ghana, Kenya driven y profit by tc companies; more informal systems linked to macro propagation in East and Central Africa. Quality control remains a challenge. Systems dependent; affordable though labour intensive e g BXW Mgt in central Africa No significant field application but may be applied as part overall IPM Accepted by most as the way forward but information and technology gaps linked to weak policies constrain application. Tushemereirwe et al 2009 Tripathi, 2011 Viljoen, 2010 Ssekiwoko 2010 Stover 2000; Viljoen 201; Blomme 2012.

27 What can and can not be done is influenced by a host of interactive factors: Limited collaboration within and between countries and regions, resulting in disfunctional management strategies and unchecked movement of pests and diseases across boundaries. The agro-ecologies, farming systems (cultivar sets in various food systems) and farming objectives, all influence management options and decisions Particularly in Africa smallholder systems dominate banana production and the socioeconomic setting; resources, labour, knowledge and information, infra-structure and local policy environment will interactively determine what can/can not be done. The agro-ecology in question and how the biophysical systems respond and/or impact on the crop and associated biodiversity

28 Thank you for listening to me