New Agriculturist - Developments 01-1

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					New Agriculturist - Developments 01-1
Unearthing a solution to cassava root rot
During the past decade, Cassava mosaic disease (CMD) has been the focus of extensive collaborative research to understand the nature of the disease and to develop resistant varieties of cassava. However, another disease, although currently confined to the East African coast, can render susceptible varieties unusable if cassava roots are left in the ground for over nine months. Like CMD, Cassava Brown Streak Disease (CBSD) is a viral disease. But, unlike the mosaic symptoms of CMD, the foliar symptoms of CBSD are less conspicuous and farmers are often unaware of the problem until the crop is harvested and the corky, yellow-brown necrosis affecting the roots becomes evident. As a two-way approach to controlling the disease, scientists at NRI and the University of Bristol in the UK, through the DFID-funded Crop Protection Programme, are working to identify the virus and its vector and to produce virus-free material for distribution to farmers. Disease prevalence Estimates of mean losses attributed to Cassava Brown Streak Disease on a national or regional basis are hard to make as the extent of loss depends not only on the susceptibility (or sensitivity) of the cultivar but also on when the crop is harvested. However, results from recent research have shown reductions in root weight of up to 20% and a further 30-40% loss due to roots being rendered unsuitable for consumption. Through work conducted in Tanzania, disease incidence for the coastal region is known to be about 20% and, in Mozambique, a recent survey has revealed CBSD to be particularly prevalent: sometimes as high as 80-90% in parts of the coastal area of two of the northern provinces. However in individual fields, 90-100% incidence of CBSD is not uncommon in coastal areas of both Tanzania and Mozambique. The disease also occurs in Kenya and may well be present elsewhere. Disease control Although farmers may not recognize Cassava Brown Streak as a viral disease, they are aware of the resulting root rot symptoms. Farmers need to be made aware of what causes these symptoms and be given advice on control. One management option is to harvest earlier as necrosis tends to affect roots of sensitive varieties from 5-6 months after planting. But early harvesting to avoid the effects of the disease still results in reduced yields because the crop is not in the field long enough to reach its full yield potential. In Tanzania, a number of local cultivars, currently grown by farmers, appear to show some resistance or tolerance, to CBSD. These have now been taken into trials to be evaluated more closely and those that demonstrate potential to resist the disease are being multiplied. Farmers will then be able to make their own choices about which of the varieties they prefer to grow from cuttings in order to multiply and subsequently pass material on to neighbours and neighbouring villages. And, in the long-term, Rory Hillocks of NRI believes that farmers are the key to managing this disease. “Although virus-free planting material is being released to farmers, that isn‟t the end of the story as every year farmers are selecting their own planting material and every year they are the ones that must be responsible for continuing to ensure that their planting material stays free of viral diseases.” Dr Hillocks feels very strongly that raising awareness amongst farmers is vital – not just in areas where the disease is known to be prevalent – but also in other regions where the disease could become evident. However, he stresses that organizations involved in distribution of cassava planting material to farmers have a responsibility to ensure that the cuttings are free of mosaic and CBSD. Understanding more about CBSD will also contribute to the further control of the disease. Through work conducted by the University of Bristol, the virus that causes Cassava Brown Streak has recently been identified. The identification of the virus indicates that, as with the CMD virus, the CBSD virus may also be transmitted by whiteflies. Closer attention is therefore being focused on the two whitefly species that occur in East Africa as possible vectors of the CBSD virus.

Phoning for fingerlings?
You wait your turn to use the phone. You dial. You wait. Silence. The connection breaks. You try again. In some countries it can be a very frustrating business trying to place an order by telephone. For fish farmers in a country such as Cameroon, where telephones as well as fish farmers are few and far between, trying to place an order for fingerlings is no easy task. Even supposing you have relatively easy access to a telephone, it is probable that you will have some distance to travel by road to collect the order. Unexpected delays on the road are not uncommon. They can be infuriating for the driver... and fatal to the fish. If pond owners could raise their own fingerlings, fish farming would be a far more attractive enterprise. Catfish sell for twice the price of tilapia, and their taste is preferred, but they have a serious drawback for fish farmers. Like most fish they need environmental stimuli, such as rising water levels, before they will breed and lay eggs. In artificial ponds with clean, well-regulated water levels, the female African catfish (Clarias gariepinus) is very reluctant to lay her eggs. Catfish eggs, larvae and fingerlings can be raised in hatcheries, and these also have the advantage of keeping the young safe from predators, but hatcheries require an expensive infrastructure and are beyond the means of all but big commercial or government enterprises. However, pond owners wishing to raise

catfish in the Western Province of Cameroon may soon be able to take advantage of development work at the Institute of Agricultural Research and Development‟s hatcheries in Foumban. Concerned about the difficulties that pond owners face in obtaining fingerlings, Steve Sulem, research scientist at the Institute, has been testing the Asian system of „hapas‟ under Cameroon‟s conditions. Hapas are small mesh net cages, usually about a metre square and can be made out of the kind of bags in which rice is sold. They are placed in ponds, with the rim above water level, so that the larvae or eggs put inside them cannot flow out. The bottom may reach the floor of the pond and inside a layer of bottom mud can be placed in order to encourage the development of small organisms which the fish can eat. The top can be covered to protect against predators. Pond owners can buy hormones from a pharmacy more easily and with less risk than buying fingerlings. The hormones are injected into the female fish which then lays eggs. A male fish (easily identifiable) is killed, its testes are removed and pressed over the eggs to fertilize them. They are then mixed with water and sprayed into the hapas. In a few days, depending upon temperature, the fish larvae will hatch and grow on in the hapas, secure from predators, until they are large enough to be let out into the main pond. Steve Sulem is convinced that pond owners will find this system simple to learn and practise... and far easier than struggling with the telephone system.

Consensus building in the Caribbean
Sun, sea and sand may be the attraction for 20 million tourists visiting the Caribbean each year but what effect is this having on the natural resources? More tourism means greater income for many in the islands but it also results in greater pollution and land and coastal degradation. Many local people, particularly in the smaller islands, are dependent on coastal resources, the mangroves and reef fisheries, which are increasingly vulnerable to the expansion of hotels and associated leisure activities. And yet, despite the seemingly conflicting demands of different sectors of these island communities, effective methods have been developed in Tobago to bring about successful co-management of the Buccoo Reef Marine Park. In addition, the techniques developed with the local institutions are being used elsewhere in the islands of Trinidad and Tobago where conflicting interests have arisen. Tactical techniques The Buccoo Reef Marine Park, an area of mangrove lagoons and a large coral reef, is situated off the most densely populated area of the island. As Tobago's most popular attraction, the area is central to the tourist trade but many are also dependent on the same natural resources for their livelihoods. In 1995, a management plan for the Park was developed but insufficient consideration was given to the views of those most affected by this plan and consequently it was not well received. This led to many difficulties concerning the enforcement of regulations and the integration of local and national needs. It was generally perceived that if a strategy for implementing sustainable use of coastal resources was to succeed, then it was vital that all those dependent on the development of the area were consulted and allowed a voice in the decision-making process. With increasing evidence to show that greater involvement of local communities is more likely to result in long-term positive outcomes, a project funded by the DFID Natural Resources Systems Programme was initiated to analyze the conflicts and trade-offs between different uses and users of the protected marine areas. With the support and guidance of researchers from the UK University of East Anglia, a series of meetings was organized to allow interested parties the opportunity to discuss their priorities for development. The team used a number of techniques and developed an approach called 'Trade-off Analysis'. As a result, although many were in favour of economic growth, the overwhelming consensus was for maintaining the health of the complex eco-system upon which they all depended. Maintaining the flow of information and establishing trust has been key to this consensus building process. Participatory approaches are generally known to be empowering for local people but, at the same time, government departments can feel that the techniques are confrontational or threatening. In working with regulatory agencies, such as the Department for Environment and Planning, the Institute of Marine Affairs and the Tobago House of Assembly, experience has shown that it was vital that all important contributors were included in the discussions and were not alienated during the process. And, despite concerns that it would be difficult to resolve conflicts between different users, each group is prepared to take responsibility for helping to solve immediate problems and to work together towards a common purpose. Successful sustainability? Consequently, an on-going forum, the Buccoo Reef Stakeholder Group, has been established in partnership with the Tobago House of Assembly to develop and sustain the co-management strategy for the Marine Park. This forum is now known throughout the island. Similar techniques are being adopted and adapted in developing Trinidad and Tobago's protected area system, for example at Nariva Swamp a wetland area on the east coast of Trinidad, which is to be designated a national park. Lessons for the rest of the Caribbean have also been drawn out of the project and are being promoted through the Caribbean Natural Resources Institute (CANARI) which is using Trade-off Analysis in training workshops on natural resource management. In addition, CANARI is hosting a regional seminar in Tobago in January 2001 for senior regional managers to provide a forum exchange experiences in techniques and policy issues involved in participatory natural resource management. A manual on Trade-off Analysis, produced by the project, will be used at the seminar and be made available regionally. Interest has already been shown for its use in other ecosystems and regions when it was recently presented at an International Coral Reefs Symposium - and not

just in the developing world. One instance is the application of Trade-off Analysis that is currently being used for forest resources management in Canada.

Filipino remedy
Step inside a clinic anywhere in the Philippines and the chances are that many of the patients seek treatment for similar complaints. Chest infections, coughs and other respiratory problems are amongst the commonest conditions seen by health workers but now the traditional herbal remedy for these ailments may prove just the right tonic for the ailing agricultural economy of an island in the far south of the country. From the air, northern Palawan – a narrow forested island that stretches for 400 km between the Sulu and the South China Sea - looks green and productive. But looks can be deceptive. Most of the five hundred families who till the mountain slopes and flat land beside the sea lack even the simplest of tools to make working the land easier and are unable to afford inputs to improve yields. The forest that cloaks the hills and protects the water catchment is being cleared at the rate of 5 hectares per year per farming household in order to get fertile land. And it is not just the trees that are falling. Average farm incomes have reached an all-time low prompting a local development organization to look for alternatives for this potentially productive area. “We wanted to find sources of cash that farmers in northern Palawan can depend on,” says Lawrence Padilla, Executive Director of Palawan Centre for Appropriate Technology (PCART ). Walk up behind many a village and it is not long before you come across a straggly delicately-leafed shrub known locally as lagundi (Vitex negundo). An infusion to treat coughs is prepared from boiled lagundi leaves but a less bitter and more convenient remedy is marketed throughout the Philippines in tablet form. Now proven scientifically to be an effective and safe treatment for a range of respiratory problems, sales of the tablets are increasing pushing up demand for dried lagundi leaf. Farmer Bonifacio Navaroza speedily snips his way around a lagundi shrub and the leafy branches fall straight into a large woven basket. He manages the first lagundi farm established to test how much each bush can produce and to interest farmers in the surrounding area in growing it themselves. One of the main attractions is that to establish a lagundi plantation there is no need to completely clear the land. Ring weeding around each young plant is all that is necessary until it is well established and the first cut of leaves can be just 8 months after planting and then every 4-6 months after that. “I like growing a plant that is made into medicine,” says Navaroza, “But the main advantage to me is that it is not like other crops where you have to plant every season. This you plant once and then just keep of harvesting it for years.” Fresh-picked leaves are taken to a central sorting shed to reject any that are damaged or diseased and then tipped onto large metal trays. Nick Aldridge, a British volunteer with Voluntary Service Overseas has brought his skills as a herb farmer in southern England to help PCART develop a hot air drier which has reduced the drying time from 48 hours to just 16. In each of three chambers 30 kilos of fresh lagundi leaves lose 50% of their weight and are ready for milling. Lower down the valley, in the new purpose-built semi-processing plant a cloud of green dust billows out as the hammer mill pounds the dried leaves to a fine powder ready for shipping to the pharmaceutical company in Manila that will press it into pills. In the corner the first order of 100 kilos is packed and ready to go. Although the company they supply has offered to buy all they can produce, PCART is well aware that they only have a narrow advantage on farmers on neighbouring islands who are also interested in growing lagundi. “That‟s why we are looking into the commercial cultivation and processing of 27 medicinal plants” Lawrence Padilla explains. Growing lagundi amongst a range of other food and herbal crops is what is recommended. “That‟s why we advise farmers never to be married to one crop alone” adds Beatrice Dioso, PCART agricultural officer, who often uses the Filipino love of gambling to get her advice to farmers. For some of the poorer farmers of Palawan, going into lagundi growing could be one gamble that does pay off.
Article written by Susie Emmett

Lake Victoria islanders – out of the frying pan?
The people who live on Bugala have traditionally earned their livelihood from the waters that surround their island in Lake Victoria in East Africa. But the waters have become so clogged with water hyacinth that this source of livelihood is in jeopardy. The plan to grow oil palm on part of the island‟s 29,600 hectares, and to build an oil palm extraction and refinery plant, was intended to reduce Uganda‟s import bill for vegetable oil but it could also have brought an alternative source of livelihood to the islanders. Now that has faltered. (See News). The islanders must be wondering if they have jumped out of the frying pan into the fire. Implementation of the Vegetable Oil Development Project on Bugala Island in Lake Victoria has stalled as a result of environmental concerns raised by, among others, the National Environment Management Agency (NEMA). The grounds on which they are basing their challenge are potential soil erosion and siltation of Lake Victoria as a result of clearing vegetation for the palm plantation, and the disposal of chemical waste from the would-be oil palm factory. According to the Ministry of Agriculture, the government wants the project to succeed because Uganda has, for a long time, been importing 75 percent of its vegetable oil and fat products at an estimated annual cost of over US$100,000. Furthermore, Uganda's edible oil intake is only 2.3 kg/capita, lower than the 3.3 kg/capita

recommended by the World Health Organisation. Ms. Connie Magomu Masaba, the technical officer in charge, says the government has prioritised the development of palm oil because of its economic value. She says the project would save Uganda over US$60 million annually in imports. The project is supported by a US$60 million loan from the International Fund for Agricultural Development (IFAD), BIDCO (the prospective investor), and the Ugandan government. Farmers will also contribute to its funding. Protestors claim that the government‟s plans to deregister more than half of the island‟s 6,500 hectares of protected forest estate, to allow more land for palm oil production, will threaten a unique flora and fauna. The move would also affect the European Union‟s five-year forestry programme which is intended to support the development of eco-tourism on the island. The government has appointed a 10-man team of academics to study the concerns.
From an article supplied by Ben Ochan, Uganda


				
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