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Terror of Bengal By Soumili De.

Updated: Jun 23, 2021

Yes have you ever heard about the plant Eichhornia crassipes or Water hyacinth. If no then you will know today. It is the most invasive aquatic weeds which is found growing wherever , there is standing water. It was first introduced into the U.S in 1884 at the Cotton States Exposition in New Orleans as an aquatic ornamental plant. Water hyacinth grows in all types of freshwaters. It is a perennial free floating aquatic plant with long dark roots. This plant varies in size. It was introduced in India to reduce the pollution. It had been considered as the most invasive aquatic plant in the united states since 1984, in Africa since early 1900s, in Asia since 1902, and in Europe since 1930s. Water hyacinth can doubles itself within 5 to 15 days. It has significant negative impacts on the ecosystem.


Besides its negative impact it has been widely planted all over the world because its beautiful, striking flowers. It has clogged water bodies including wetlands at many places and also blocks sunlight. Water hyacinth consumes oxygen (O2) from the water which leads to death of many aquatic animals like fishes. Eichhornia forms dense, impenetrable mats which clog waterways, making boating, fishing and almost all other activities impossible. Water hyacinth mats also degrade water quality by blocking air-water interface. It propagates vegetatively very rapidly and spread all over the water body in a very short of time so it is very difficult to get rid off. Water hyacinth is called “ scourge of water bodies” or the “terror of Bengal”. It is one of the cause among the four evil quartet that lead to the loss of biodiversity. Water hyacinth includes in the Alien Species Invasion, where an exotic species deliberately for their economic uses or unintentionally, often causes disappearance of native species.


It is not recommended by UF/IFAS. It is a prohibited plant according to the FDACS Florida Noxious Weed Index and therefore illegal to possess. In Bengaluru, the Indian Army deployed 7000 of its personnel to clean the Ulsooru lake, and their efforts has proved futile. Many researches across the world have been striving to make use of these aquatic weeds for creative purposes.

Meaures to control the spreading of water hyacinth can be classified into 3 types – chemical control, physical control and biological control. Chemical control is the least used out of the three controls of water hyacinth, because of its long-term effects on the environment and human health. The use of herbicides requires strict approval from governmental protection agencies of skilled technician to handle and spray the affected areas. The use of chemical herbicides is only used in case of severe infiltration of water hyacinth. 

However, the most successful use of herbicides is when it is used for smaller areas of infestation of water hyacinth. This is because in larger areas, more mats of water hyacinths are likely to survive the herbicides and can fragment to further propagate a large area of water hyacinth mats. The herbicide known as diquat is a liquid bromide salt that can rapidly penetrate the leaves of the water hyacinth and lead to immediate inactivity of plant cells and cellular processes. For the herbicide glyphosate, it has a lower toxicity than the other herbicides; therefore, it takes longer for the water hyacinth mats to be destroyed (about three weeks). The symptoms include steady wilting of the plants and a yellow discoloration of the plant leaves that eventually leads to plant decay. Mechanical removal is seen as the best short-term solution to the proliferation of the plant. A project on Lake Victoria in Africa used various pieces of equipment to chop, collect, and dispose of 1,500 hectares of water hyacinth in a 12-month period. It is, however, costly and requires the use of both land and water vehicles, but it took many years for the lake to become in poor condition and reclamation will be a continual process. However, transportation and disposal of the harvested water hyacinth is a challenge because the vegetation is heavy in weight. The harvested water hyacinth can pose a health risk to humans because of the plant's propensity for absorbing contaminants, and it is considered toxic to humans. Furthermore, the practice of mechanical harvesting is not effective in large-scale infestations of the water hyacinth, because this aquatic invasive species grows much more rapidly than it can be eliminated. As chemical and mechanical removal is often too expensive, polluting, and ineffective, researchers have turned to biological control agents to deal with water hyacinth. The effort began in the 1970s when USDA researchers released into the United States three species of weevil known to feed on water hyacinth, Neochetina bruchi, N. eichhorniae, and the water hyacinth borer Sameodes albiguttalis . These organisms regulate water hyacinth by limiting water hyacinth size, its vegetative propagation, and seed production. Another insect being considered as a biological control agent is the semi-aquatic grasshopper Cornops aquaticum. This insect is specific to the water hyacinth and its family, and besides feeding on the plant, it introduces a secondary pathogenic infestation. This grasshopper has been introduced into South Africa in controlled trials.


Water hyacinth is also usefull in many purposes other than ornamental plants. Indian farmers collect and pile up these plants to dry at the onset of the cold season; they then use the dry water hyacinths as fuel. The ashes are used as fertilizer. In India, one tonne of dried water hyacinth yields about 50 litres of ethanol (CH3CH2OH) . Water hyacinth removes arsenic from arsenic -contaminated water. It may be used as an useful tool in removing arsenic from tube well water in Bangladesh. Water hyacinth is also observed to enhance nitrification in wastewater treatment cells of living technology. Their root zones are superb micro-sites for bacterial communities.



About The Author

Soumili De is a student of 12 .Her hobbies are dancing,singing, drawing etc. She is specially interested on doing research work .


DISCLAIMER

The idea of the above painting belongs solely to the painter, Ms Soumili De.


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