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  • Strategies for Water Hyacinth Control

    Report of a Panel of Experts Meeting 11-14 September, 1995

    Fort Lauderdale, Florida USA

    Edited by:

    R. Charudattan Ricardo Labrada

    Ted D. Center Christine Kelly-Begazo

    Food and Agricultural Organization of the United Nations

    Rome, 1996

    Published in collaboration with the:

    University of Florida, Gainesville Institute of Food and Agricultural Sciences

    International Programs for Food, Agriculture and Natural Resources and the USDA/ARS

    Aquatic Plant Control Research Laboratory Fort Lauderdale, Florida



    International Expert Consultation on Strategies for Water Hyacinth Control: Background and Justification R. Labrada, R. Charudattan, and T.D. Center Status of Water Hyacinth in Developing Countries R. Labrada Region A - West Africa: Benin, Ghana, and West Africa Biological Control of Water Hyacinth in Benin, West Africa P. Neuenschwander, O. Ajuonu, and V. Schade Integrated Control of Aquatic Weeds in Ghana K.A.A. de Graft Johnson The Water Hyacinth Problem in West Africa and Proposals for Control Strategies A.H. Pieterse, A. Mangane, M. Traor, G. van de Klashorst, and P.J. van Rijn

    Region B - East and Southern Africa: Malawi, South Africa, and Uganda

    The Water Hyacinth Problem in Mala_i and Foreseen Methods of Control P.J. Terry An Integrated Water Hyacinth Control Program on the Vaal River, in a Cool, High Altitude Area in South Africa C.J. Cilliers, P.L. Campbell, D. Naude, and S. Neser Water Hyacinth: Its Problems and the Means of Control in Uganda F.L. Orach-Meza

    Region C - Australia An Outline of Water Hyacinth Control in Australia A.D. Wright

  • Region D - North America: Mexico and USA Water Hyacinth Problems in Mexico and Practised Methods for Control E. Gutierrez Lpez, R. Huerto Delgadillo, and M. Martnez Jimnez Operational Aspects of Chemical, Mechanical and Biological Control of Water Hyacinth in the United States W.T. Haller Water Hyacinth Control Program in USA Al. F. Cofrancesco Biological Control of Water Hyacinth in the United States T.D. Center

    Special Section: New and Additional Agents for Biological Control and Steps in Implementing Integrated Management Programs Recommendations for Finding and Prioritizing New Agents for Biocontrol of Water Hyacinth H.A. Cordo Pathogens for Biological Control of Water Hyacinth R. Charudattan Steps in Implementing Integrated Management Programs Against Water Hyacinth S. Nesser

    Conclusions and Recommendations of the Expert Panel: Intergrated Control of Water Hyacinth in Developing Countries with Emphasis on Biological Control List of Participants Appendix: Meeting Agenda Acknowledgements

  • 1

    INTERNATIONAL EXPERT CONSULTATION ON STRATEGIES FOR WATER HYACINTH CONTROL: BACKGROUND AND JUSTIFICATION R. Labrada1, R. Charudattan2, and T.D. Center3 1Food and Agriculture Organization of the United Nations (FAO), Rome, Italy, 2Plant Pathology Department, Center for Aquatic Plants, Institute of Food and Agricultural Sciences, University

    of Florida, and 3USDA-ARS Aquatic Plant Control Research Laboratory, Fort Lauderdale, Florida

    One of the major problems in water bodies of the tropics and sub-tropics is the floating aquatic weed water hyacinth Eichhornia crassipes, which is considered to have originated from the Amazon and has disseminated very quickly in various tropical and sub-tropical countries of Latin America and the Caribbean, Africa, Southeast Asia and the Pacific. The level of reproduction of water hyacinth is very high in countries where the plant has recently been introduced. The explosive growth rate of the weed is due, to a large extent, to the eutrophication in water bodies. In addition, the absence of natural enemies of the plant contributes to the rapid growth of this weed. It is well known that biological control is one of the most successful methods to control water hyacinth. The method, practised for example successfully in Australia through the regular release of the weevils Neochetina eichhorniae and N. bruchi, and the moth Sameodes albiguttalis, has been recently adopted in some countries of Latin America and Africa and it is expected to have the same impact as in Australia. However, in many countries the water bodies present very heavy infestations in different sites (fish landing areas, docks, hydroelectric power stations, rivers and dams), and there is a general consensus that other short-term control measures should also be implemented to reduce the weed stands and also to benefit the growth of natural enemies for successful biological control. Among the short-term control measures there are physical (mechanical and manual) removal and chemical control. All have serious constraints for implementation in water bodies of developing countries of the tropical and sub-tropical regions. Mechanical removal requires the purchase of harvesters, many of them too costly for most of developing countries. Manual removal requires a large labour force, and Governments of the developing world do not always have the means to pay for this operation. Chemical control, through the use of certain herbicides such as 2,4-D or glyphosate, seems to be an economically feasible option in some countries, but not in others with less economic development. In addition, in many countries public opinion is strongly against the use of chemicals in water, which is used for drinking purposes.

  • 2

    FAO, taking into consideration the seriousness of the problem and the need to develop a strategy for integrated water hyacinth control, has decided to organize, in close cooperation with USDA and University of Florida, the present expert technical consultation.

    EXPECTED OUTPUTS 1. Suitable guidelines for water hyacinth control in developing countries of the tropical and sub-tropical regions. These guidelines should clearly indicate the strategy for implementing available control methods. 2. An updated status report of biological control of water hyacinth (natural enemies and methods for rearing and release available) giving relevant advice on ways for its rapid implementation and success in countries of the developing world. PARTICIPANTS Outstanding specialists on water hyacinth control from countries and/or institutions (such as CSIRO, Australia; IITA, Benin; Royal KIT, Amsterdam, The Netherlands; Long Ashton Research Station, University of Bristol and IIBC, UK) and several others from the University of Florida and USDA will actively participate in this meeting. Some other specialists from selected ongoing projects on water hyacinth control have also been invited whose participation may give the necessary background to discussions and debates. These are specialists from Uganda (Lake Victoria), Ghana and Mexico who work closely on water hyacinth control.

  • 3

    STATUS OF WATER HYACINTH IN DEVELOPING COUNTRIES R. Labrada Food and Agriculture Organization of the United Nations (FAO), Rome, Italy SUMMARY The present paper briefly describes the problems caused by water hyacinth in various countries of Africa and Latin America. It also describes the actions undertaken by FAO and other agencies and/or institutions regarding the implementation of programs for the control of this floating aquatic weed. The constraints posed by all available control methods are discussed. It is considered that, under certain circumstances, biological control of the weed alone will not be sufficient to effectively reduce the weed stand in a relatively short period of time. Therefore, an integrated approach for the control of the weed is recommended which may consist of mechanical and/or systematic manual removal, and the use of herbicides in particular infested sites. Each method has its own economic and environmental constraints, and practical advice is needed on where and how to use short-term control methods to complement the effect of biological control. INTRODUCTION It is not necessary to reiterate the noxious effects caused by the floating weed, water hyacinth (Eichhornia crassipes). There are already many papers giving valuable information about the effects of water hyacinth on water loss through evaporation, obstruction of navigation and fishing, and blockage of irrigation and drainage systems (Achmad, 1971; Desougi & Obeid, 1978; Gopal, 1987; Holm et al., 1991). Here I prefer to give an overview of the areas infested by water hyacinth in various parts of the developing world, problems caused to their national economies, and constraints to overcome them. Another aspect to be discussed is the feasibility of implementing specific control methods. There is no doubt that biological control should be the key component in any program for the control of water hyacinth. Biocontrol is an economically feasible and environmentally viable option to control water hyacinth and other aquatic weeds. However, in certain situations, biological control practised alone succeeds only after several years of implementation, and whereas what is needed in some areas of commercial value is drastic reduction in the weed population in short periods of time. Countries and Water Bodies Infested by Water Hyacinth If one looks at the latest edition of "The World's Worst Weeds" edited by Holm et al (1991) it will be noted that the map of water hyacinth distribution (figure 24 of the book) has significantly changed during the


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