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Water hyacinth

Preferred Scientific Name: Eichhornia crassipes

Water hyacinth is native to South America and is a major freshwater weed. It was originally introduced as an ornamental plant due to its striking flowers, but has since spread at an alarming rate. 

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Why is it a problem?

Water hyacinth has a negative impact on water transport and restricts access to ports; negatively impacting trade and food security. It also blocks water turbines used for electricity generation, hampering economic development. It provides habitats for disease vectors, including malaria. The weed also impacts fishing. Large infestations can also lead to de-oxygenation of the water which can reduce fish stocks.

Impacts

  • Reduces irrigation flow
  • Damages fishing equipment
  • Reduces fish stocks and native biodiversity
  • Negatively impacts livelihoods

What’s the solution?

Chemical control

Studies have shown that the spread of the weed is dependent on levels of nitrogen and phosphorus in the water. By reducing the nutrients in the water, the growth of the plant can be slowed down. Herbicides such as 2,4-D have also proved to be effective if used under conditions of rapid growth and high humidity. In these conditions most of the plants will die and sink. However, the weed needs to be treated repeatedly in order to control it effectively. 

Biological control

Seven arthropods and three fungi were developed as biocontrol agents. As well as this, two Neochetina weevils have been known to reduce Water hyacinth infestation by up to 90%. Permanent control has been reported in some areas.

Stories related to this content

Stanley Mungai

Stanley Mungai

Kenya

Stanley Mungai has been a fisherman on Lake Naivasha, a freshwater lake, for 30 years. He has seen his home change and his livelihood suffer as a result of severe Water hyacinth infestation. 

Fact file

Name Water hyacinth

Distribution

Asia, Africa, North/South/Central America, Oceania &Europe

For more information on distribution, view the full datasheet available here

Habitat

Freshwater

Natural enemies

Over 100 different insects attack the plant. However, most of these cannot be used as a biocontrol agent because they attack plants native to the region in which they are introduced

Invasiveness

Invasive in both its native and non-native range, tolerates control and spreads quickly

Likelihood of entry

Often introduced intentionally

Climate

Tropical/ subtropical 

Plant type

Aquatic 

Further reading

Visit our online resource of research and full text articles and journals
Invasive Species Compendium

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