In brief

Banishing black sigatoka in bananas

Research in the South Pacific has identified banana varieties with potential resistance to black leaf streak, also known as black sigatoka. The promising disease-resistant material has been screened from banana varieties imported to Western Samoa from Queensland, Australia.

The disease was first recorded in Java in 1902 and in 1912 appeared in the Sigatoka Valley of Fiji, from whence it acquired its name. However, the disease was only recognized as a major threat when a very virulent form was detected in Fiji in 1963. Distinguished by severe dark brown and black spots and streaks on affected leaves; it was typified as black sigatoka or black leaf streak. Whereas the original mild form of sigatoka is caused by Mycosphaerella musicola, the virulent black leaf streak is caused by M. fijiensis.

The disease has spread to many parts of Africa and to parts of the Caribbean basin. It is approximately three to six times more expensive to control M. fijiensis than M. musicola using fungicide spraying. The development of resistant varieties would be of great economic benefit to bananadependent economies in the ACP countries.

• Kirifi Pouono Crop Protection Section Ministry of Agriculture Nuu WESTERN SAMOA

Taro - in or out of trouble?

Research workers at Western Samoa's Crop Protection Station at Nuu have isolated four strains of taro (Colocasia antiquorum) that are resistant to taro leaf blight. Taro, also known as cocoyam in Africa and eddoes and dasheen in the Caribbean, is the main staple food of Western and American Samoa as well as Tonga. It has been a major export for Western Samoa, the produce going to Australia and New Zealand where the tuber is much in demand from the large resident Polynesian communities. Within months of taro leaf blight appearing in Western Samoa in 1993, the crop was effectively destroyed by the disease depriving the country of substantial export earnings and costing Western Samoa foreign exchange to import taro from neighbouring countries.

A concerted screening of taro from many countries has yielded two tolerant varieties from the Philippines and two from the Federated States of Micronesia. They are of the talo munua and talo paepae varieties. Other varieties from Hawaii and India are still to undergo tests at Nuu and the Samoan research workers are also in contact with colleagues in Africa and the Caribbean about other possible species of taro found there.

The Nuu researchers aim to breed a new variety of taro based on the locally popular but blight susceptible variety Niue crossed with imported tolerant strains. They hope to have new resistant taros on the market in 1997 and to win back 60% of their export market within five years.

Other countries in the Pacific which have suffered severely from taro blight include Papua New Guinea and the Solomon Islands. They have also had to contend with two additional pests, a taro beetle and a taro virus.

These pest and disease outbreaks in the Pacific emphasize the need for continuing vigilance and quarantine when importing plant or animal products.

• Dr Semisi Semisi

Asst. Director of Research

Crop Protection Section

Ministry of Agriculture

Nuu WESTERN SAMOA

Wanted dead or alive!

The demand for dead wood for fuel and to construct fences and livestock enclosures has contributed to widespread deforestation in the Sahel. To take the pressure off surviving vegetation, villagers in Burkina Faso have been encouraged and assisted to establish living fences.

The species selected for planting as live fences contribute to farmers' well-being and income in several ways: by controlling livestock, damage to high value crops, including vegetables, is avoided and farmers can now benefit from the increasing demand for fresh produce in nearby towns.

Four species have been selected, three of which are thorny and provide good barriers to animals: Acacia senegal, Ziziphus mauritania, Acacia nilotica and Bauhinia rufescens, the only one without thorns. A. senegal provides Gum Arabic and fodder and A. nilotica is used for tanning and medicinal purposes. Ziziphus mauritania yields fruits for consumption and sale, while the leaves of both Ziziphus and Bauhinia are used for animal fodder.

To form an effective barrier the four species are planted in a continuous but staggered double row with 50cm between plants in the same row and 25cm between the rows. The outside row consists largely of A. nilotica, while the other three species are planted in equal numbers to form the inner row of plants.

Productivity is said to have increased by an extra US$60-100 per season. In Burkina Faso the average annual income is less than US$300.

The project, which is centred on the village of Konki Ipala (37km west of Ouagadougou) is a collaborative effort between the Institut de Recherche en Biologie et Ecologie Tropicale (IRBET) and the International Centre for Research in Agroforestry (ICRAF).

Elias Ayuk ICRAF PO Box 30677 Nairobi KENYA

When a weed can be a crop

Women farmers across Africa have developed techniques for managing plant species that, under certain circumstances, could be perceived as weeds. For example, once established in the soil cocoyam tubers will sprout rapidly and compete vigorously with planted groundnut. To avoid competition with their crops, women farmers in Cameroon cut back the leaves of the cocoyam to arrest its growth and allow the groundnut crop to flourish. But, once the groundnut has been harvested, the cocoyam is left to grow among the succeeding cassava crop since there is little competition between the two species.

Water leaf (Talinum triangulare) is another species which, if left unmanaged, acts as a weed in cultivated fields. But it can be eaten as a leaf vegetable and some farmers remove the majority of water leaf plants to reduce competition with their cultivated crop and leave enough to be used for home consumption.

Chromolaena odorata was introduced to West Africa early this century With its rapid vegetative development and production of large numbers of airborne seeds this weed has quickly established itself across large areas of the region. Once established it develops into a dense thicket, which can be exceedingly troublesome to farmers. But the plant has now become an important component of the short fallow, slash-and-burn cropping system. As a fallow species, C. odorata provides large quantities of nutrient-rich humus which improves the texture and mineral content of the soil. An added advantage is its successful suppression of another extremely problematic and noxious grass weed, Imperata cylindrica. Although Chromolaena can offer an advantage compared to Imperata, it has led to a heavier workload for women and children responsible for weeding crops. This has followed the general pattern in the shift of dominance in weed species as fallow periods become shorter. Researchers have been told by women farmers that the easier-to-weed species such as Triumfetta cordifolia and Trema orientalis, are being replaced by species such as Ageratum conyzoides and Sida rhombifolia, which are far more labour intensive to weed. The challenge for researchers is to develop integrated weed management strategies which will make a real difference in the lives of women farmers and, in the case of Chromolaena, to reduce its negative effects during the cropping cycle and enhance its soil improvement properties during the fallow phase.

• IITA PMB 5320 Ibadan NIGERIA

Hands-on crop conservation

The conservation of plant genetic resources at farm level has been recognized by the International Plant Genetic Resources Institute (IPGRI) as having an important role in saving potentially useful varieties, and even species of plants, from extinction. Such in situ conservation makes a direct contribution to the well-being of communities, according to Dr Toby Hodgkin, Director of the Genetic Diversity Group at IPGRI. He adds that by ensuring that traditional varieties of crops remain available to farmers for their own use, it allows for more sustainable agricultural development than when there is reliance on only one or two specific types.

Ethiopia is one country enthusiastically pursuing this on-farm conservation. As one of the world's most important centres of agricultural biodiversity, Ethiopia has already demonstrated itself as a leader among African countries in the development of both gene banks (ex situ) and on-farm (in situ) conservation. The Biodiversity Institute in Ethiopia has as one of its main objectives the support of farming communities in their efforts to maintain crop diversity and to achieve food security at household level.

This work in Ethiopia is being financed through the Global Environment Facility (GEF), while IPGRI is assisting with technical support.

• Dr Toby Hodgkin

Director, Genetic Diversity Group

IPGRI

Via delle Sette Chiese 142

00145 Rome, ITALY

Newsletter reappears

In August 1995, the first FAO/IDF Dairy Development Newsletter was published. More than 500 copies were distributed to ministries, institutions, universities and professionals of the dairy sector for developing countries. Due to budget and personnel reductions it was not possible to print any issues in 1996. Reallocation of funds, however, will now permit publication of two issues per year for 1997 and 1998; the first of these will be available in June.

The next issue of the Newsletter will cover: strategies for meat and milk distribution in big cities; technology development for milk collection, processing and marketing; milk producers' organization for inputs and services; regional dairy information network programme; world and regional milk and dairy products outlook; and FAO and IDF meetings, workshops and publications.

The Newsletter is distributed free-of-charge and people wishing to ensure that their names are registered on the mailing-list should contact either of the following:

• J-C Lambert Dairy Officer FAO/AGAP Viale delle Terme di Caracalla 00 100 Rome ITALY • Ernest Mann IDF 41 Square Vergotte 1 030 Brussels BELGIUM

Virtual palms give real results

Palm oil production should benefit from a new computer simulation program developed by scientists at the French agricultural development agency, CIRAD (Centre de cooperation internationale en recherche agronomique pour le Développement The program allows researchers to grow 'virtual' crops of oil palm under different regimes of climate and management and to assess the consequences of planting at different spacings, the application of fertilizer and pesticides and the effects of changing rainfall on palm growth and oil yield.

The program has been written by Frederic Blaise and his team at CIRAD and is based on 12 years of measurements of real palms growing in the field and several refinements to the initial program. Now, in just a few hours following 'planting' the growth of the cyber palms is complete and the results of various climatic and management factors can be seen.

The program should contribute to the improvement of palm oil production in West Africa and benefit those farmers and national economies dependent on oil palm. (See also BEAM p9 Spore 64).

• Frederic Blaise CIRAD BP5035 34032 Montpellier Cedex 1 FRANCE

Assembly of African coffee producers

When members of the InterAfrican Coffee Organization (IACO) convened in Abidjan, Côte d'lvoire at the end of last year they reviewed the world coffee market situation and discussed activities relating to African coffee production and export.

In relation to the world market situation, it was noted that although African coffee production is Improving, and despite favourable supply and demand factors, prices are stagnating and overall revenue for 1996/7 is likely to be 40% lower than two years ago. In the light of weak prices, the Assembly agreed that the African Coffee Producing Countries (ACPC) export volume previously agreed in July 1996 should be reviewed to ensure that surplus stocks in importing countries continued to decline. It was also decided that high level diplomatic initiatives should be launched with ACPC partners in Latin America and Asia so that common measures might be taken in future to strengthen world prices.

In relation to the African Coffee Rehabilitation Programme, the meeting noted that after a period of continuous decline, productivity and quality have been improving. African coffee production is now estimated at 17.2 million bags per year. Progress in areas of disease control by member countries was also noted to be satisfactory.

• InterAfrican Coffee Organization Secretary-General

BP V'2 1 0

Abidjan

COTE D'IVOIRE

Improving diguettes

A diguette is an earthen ridge or line of stones built for water and soil conservation in parts of West Africa. The problem with traditional earthen diguettes is that within a few years they are rendered ineffective due to the damage caused by uncontrolled grazing of animals. In order to discuss ideas for improving the effectiveness of diguettes a Collaborative Technology Development Workshop was organized by the International Program for Arid Land Crops (IPALAC) with the intention of incorporating two agroforestry techniques with the diguette technology: living fences and alley cropping for mulch production.

Twelve participants from Mali, Burkina Faso, Senegal, Ghana and Nigeria attended the workshop with technical support provided by Wageningen Agricultural University, the Central Arid Zone Research Institute (CAZRI) based in Rajasthan, India, the International Institute of Tropical Agriculture (IITA) and the International Centre for Research in Agroforestry (ICRAF).

Protection of the diguettes against grazing animals can be achieved by using a living fence of prickly pear cactus (Opuntia ficus indica). The species was recommended because of its low water requirements, its compact root system, and most importantly, its effectiveness as a barrier. Additional benefits include its production of tasty and nutritious fruits and that it is an effective firebreak.

To help prevent water loss in Sahelian farming systems the participants were persuaded that many of the causes for this problem could be reduced by the application of mulch. Currently there is a lack of sufficient material available for mulch but this can be solved with the use of alley-cropping. Two species have been identified by researchers as meeting the criteria necessary for the conditions in the Sahel: Melaleuca lanceolata and Olearia axillaris. Several participants felt that some indigenous species may be just as effective for mulching and they were encouraged to investigate these further and to share their findings on the newly formed improved diguette 'network'.

Workshop participants were involved in several hands-on exercises which proved to be very successful, including collecting and handling seed and grafting techniques. These culminated in a field day exercise where an improved diguette was created using all the technologies and species discussed. At the end of the workshop participants left with sufficient plant seedlings and cuttings to help set up and evaluate the improved diguette projects in their home countries.

• Arnie Schlissel,

Administrative Coordinator

IPALAC

Ben-Gurion University of the Negev

Ernst David Bergmann Campus

PO B 655 Beer Sheva 84105 ISRAEL

New CD-ROM information

The Centre for International Forestry Research (CIFOR) has just released its first CD-ROM publication Manual of forest fruits, seeds and seedlings. The manual is based on a book of the same title which was published in two volumes by the Forest Research Institute Malaysia (FRIM) in 1991/2.

Although the original manual was intended to be a guide for the identification of tree seedlings in Malaysia, most of the genera included occur throughout Southeast Asia with many found as far apart as India and the South Pacific. With descriptions of 310 genera of trees, supported by drawings and photographs, the CDROM provides easy access to information structured through menus according to family and genus names. Additional features include free text search of the entire database contents and a botanical identification key.

The CD-ROM is a pilot publication for CIFOR which results from its mandate to provide improved access to information, build capacity and foster collaboration among its partner organizations. The CD-ROM Manual of forest fruits, seeds and seedlings can be ordered directly from the CIFOR Library at a cost of US$ 15 (including postage).

Also to be published in March 1997 is the Crop protection compendium: module 1 produced by CAB International as the first stage of a four-year project to produce a CD-ROM for global pest management. The compendium aims to meet the needs of all those who require information on practical pest management by giving easy access to data on over 1000 major pests and their natural enemies, many of which are of global importance, but with a particular emphasis on South-east Asia and the Pacific. Additional information is provided on diseases and weeds associated with 150 crops found in 150 countries worldwide.

The compendium will be updated annually and purchasers of Module 1, who wish to upgrade to the fully global Crop protection compendium in 1999, will pay no more than the difference in price of the two products. From January 1997 a fully interactive CD-ROM Windows version with selected data will be available on free trial for those interested in purchasing the compendium.

• CIFOR

PO Box 6596

JKPWB

Jakarta 1 0065

INDONESIA

• CAB International

Wallingford

Oxon

OX10 ODE

UK

New additions to Gatekeeper series

The Gatekeeper series of publications includes over sixty papers published by the Sustainable Agriculture Programme of the International Institute for Environment and Development (IIED). The series focuses on key areas of sustainable management and resource management with each paper reviewing a particular issue in order to provide preliminary recommendations for policymakers, researchers and planners. References are provided to important sources and background material.

Two of the most recent papers published in 1996 are: Intensification of agriculture in semi-arid areas: lessons from the Kano close-settled zone, Nigeria and Sustainable agriculture: impacts on food production and challenges for food security. The latter draws on two recent studies conducted by the Sustainable Agriculture Programme of IIED for the Swedish International Development Cooperation Agency (SIDA) and the UK's Overseas Development Administration (ODA).

Subscription to the Gatekeeper series, which is published three times a year, is free-of-charge. A limited number of back copies can be distributed free-of-charge on request to individuals and institutions in developing countries, but otherwise the price per copy is UKL3.00

• IIED

3 Endsleigh Street

London

WC 1 H ODD

UK

COURSES AND CONFERENCES

• MA COURSE: TELEVISION/VIDEO FOR DEVELOPMENT

October 1997

This course focuses on the use of video and television in the context of the marginalization of communities in both the Northern and the Southern Hemispheres. Course participants combine practice with theory to negotiate new perspectives on the production and reception of video/television.

Dr Pat Norrish, AERDD, The University of Reading PO Box 238, Reading RG6 6AL, UK Fax: +44 118 9261244 email: p.e.norrish@reading.ac.uk

• MANAGEMENT SKILLS FOR RURAL DEVELOPMENT

14 August-12 September 1997

This skills-oriented programme is designed to enable development professionals to improve their managerial capabilities. The course focuses on the role of information in management decision-making. Dr Penny Perkin {Short Courses Coordinator), AERDD {address as above}

Fax: +44 118 9261244 email: p.e.perkins@reading.ac.uk

• IMI COUURSES: IDENTIFICATION OF FUNG OF AGRICULTURAL AND ENVIRONMENTAL SIGNIFICANCE

11 August-19 September 1997

The course gives training in the classification and identification of economically important groups of microfungi. Particular attention will be given to those that are commonly found associated with plant diseases and are difficult to identify.

• MYCORRHIZAS-IDENTIFICATION AND TECHNIQUES

13-17 October 1997

This new five-day course is designed to provide an introduction to the isolation and preparation techniques for mycorrhizas and their identification.

• CULTURE PRESERVATION TECHNIQUES FOR FILAMENTOUS FUNGI AND BACTERIA

29-31 October 1997

This course is aimed at microbiology technicians, laboratory managers or others needing to maintain and preserve fungal and/or bacterial isolates and is suitable for those working in plant pathology, industry, food science or environmental mycology.

• PCR TECHNIQUES AND APPLICATIONS

17-21 November 1997

A new course designed to meet the needs of those already working with PCR (Polymerase Chain Reaction) techniques but needing to know more about the different applications and methods available.

Details of the above four courses from:

Mrs Stephanie Groundwater, lnternational Mycological Institute,

Bakeham

Lane, Egham, Surrey TW20 9TY, UK

Fax: +44 1784 470909

email: s.groundwater@cabi.org

• UNIVED COURSES: PARTICIPATIVE AGRICULTURAL EXTENSION TECHNOLOGY IN THE TROPICS 25 June-5 September 1997

• INDIGENOUS TECHNICAL KNOWLEDGE IN TROPICAL AGRICULTURAL DEVELOPMENT

26 June-5 September 1997

• PROJECT MANAGEMENT AND PLANNING

25 June-5 September 1997

• CUSTOMISED PERSONAL TRAINING PROGRAMMES IN GEOGRAPHICAL INFORMATION SYSTEMS

Module 1: 29 September-19 December 1997

Module 11: 12 January-27 March 1998

Yvonne Kinnaird, UnivEd Training and Conference Centre,

11 South College Street, Edinburgh, EH8 9AA, UK

Fax: +44 131 650 9019

email: yvonne.kinnaird@ed.ac.uk

• TRAINING IN INTERDISCIPLINARY TEAM RESEARCH FOR AGRICULTURAL DEVELOPMENT 12 January - 23 July 1998

Jon Daane, ICRA, PO Box 88, 6700 AB Wageningen,

THE NETHERLANDS

Fax: +31 317 427046

email: icra@iac.agro.nl

• VIII SCIENCE INTER-CONGRESS - ISLANDS IN THE PACIFIC CENTURY

to be held at the University of the South Pacific from 13-19 July 1997 in Suva, Fiji

VIII Pacific Science Association Inter-Congress Symposium, c/o School of

Pure & Applied Sciences, The University of the South Pacific, Suva, Fiji

Fax: +679 314007

• TROPICAL ROOT CROPS: STAPLES FOR SUSTAINABLE FOOD SECURITY INTO THE NEXT MILLENNIUM the 11th symposium of the International Society for Tropical Root Crops to be held from 20-28 October 1997 in Trinidad and Tobago

Dr Conrad Bonsi, Secretary/Treasurer ISTRC, G W C Agricultural

Experimental Station, R 100 Campbell Hall, Tuskegee University,

Tuskegee, AL 36088, USA

• IMPACT ON HEALTH AND ENVIRONMENT an international conference on pesticide use in developing countries to be held from 23 February-1 March 1998 in Costa Rica.

M.Sc. Yamileth Astorga, PPUNA, Universidad Nacional

Apodo. 86-3000, Heredia, COSTA RICA

Please write to the addresses given above, and not to

CTA, if you are interested in participating in these events.