Biological Control of Water Hyacinth: a Case Study of Lake Victoria Kenya.
The invasion of Lake Victoria by the water hyacinth, Eichhornia crassipes, in the early 1990s posed a serious challenge. Due to lack of natural enemies to check the plant’s growth and the high pollution levels in the Lake, the plant quickly spread to attain a peak infestation of 17,200 ha on the Kenyan side by 1998. Several management options were considered for the control of the weed including physical, biological, mechanical and chemical. Biological control was the preferred method whereas physical control was recommended on a limited scale to clear the weed in critical water intake points and fish landing sites. Kenya Agricultural Research Institute (KARI) implemented a biological control programme for water hyacinth that included importation, mass rearing and releases of exotic biological control agents. Thirteen thousand eight hundred adult Neochetina weevils were imported from Australia, Uganda and South Africa for mass rearing. Over 4.2 million weevils were released over the period of the project. There was a large reduction, in water hyacinth population to 3,134 ha in December 1999 and 532 ha in February 2000, 24 months after the release of the Neochetina weevils. Satellite images taken in December 2003 show that the water hyacinth abundance in the lake was 384 ha, while visual sampling in December 2005 estimated its abundance at 462 ha. This translates to a reduction of over 95% of the peak infestation. A total of 18 community based weevil rearing units have so far been set up in schools and beaches neighbouring water hyacinth hot spot areas. Currently the weevil production from these units is over 500,000 adult weevils and immature stages per annum.
| Main Authors: | , |
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| Format: | Report biblioteca |
| Language: | English |
| Published: |
KARI
2006
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| Subjects: | Plant control, Biological control, Freshwater weeds, Water hyacinth, |
| Online Access: | http://hdl.handle.net/1834/7243 |
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