Water hyacinth can be controlled effectively using classic biological control - four weevil species introduced from South America into Australia have provided effective control, and release of two of these has met with similar success in Papua New Guinea, Kenya, Uganda, Tanzania, benin, South Africa and Thailand. See the reference below as a starting point:

Julien, MH, Griffiths, MW & Wright, AD (1999), Biological control of water hyacinth: the weevils Neochetina bruchi and N. eichhorniae: biologies, host ranges, and rearing, releasing and monitoring techniques for biological control of Eichhornia crassipes, The Australian Centre for International Agricultural Research, Canberra

I'm sorry, we don't , since Eichornia crassipes in not a problem jet for our water bodies. Indeed we don't deal much with expansion of exotic species ... There are some pioneer project on Ludwigia exapetala, but they are driven directly by Protected Areas.

There are no effective approaches to control water hyacinth.

I remember, as a tourist, that in the Kerala backwaters (Southern India) they used to let seawater in the freshwater canals, after the harvest season. I can't tell if and how this could work, it's only a holiday remembrance.

The panama canal is regularly skimmed by teams of tugboats and small one-man boats that, together, bind great clumps of floating plant matter (including huge amounts of material washed down from the mountains during storms) using ropes, and drag it away. If course this is an energy- and labour-intensive method, the expense of which is justified by the need to keep the canal operational at all times. Attached is a photo I took on a stretch of the canal just south of Lake Gatun, the day after a particularly large storm. Although a range of plant matter is visible in this photo large clumps of Eichornia crassipes, floating like islands, were also visible at the time.

Problems can be turned into benefits if a right value proposition can be found. Water hyacinth can be harvested for biogas, fertliser or fibre production.

Biological control is the most preferred option if the level of water hyacinth infestation is not extensive and the water body does not have high nutrient levels, especially phosphate and nitrates. For eutrophic and hyper-eutrophic water bodies, alternative methods such such as mechanical and chemical control may need to be considered.

Hi Hery, water hyacinth though a environmental menace has been found suitable for the production of biogas. It does therefore suggest that if properly harnessed to this end will a good step in the right direction, especially now the whole globe is tilting towards environmental friendly production. It should be emphasized that so many countries had reduced their fossil fuel demands, which is catastrophic oil producing countries.

The way one can manage water hyacinth for benefits such as used as a biogas.

Water hyacinth being aquatic, may have potential role in managing the dissolved pollutants in water bodies. However, excess of it has caused menace which actually need to be addressed. Its being green plant is a great advantage as it posses cellulose which in turn are used for the production of ethanol followed by producing bio-fuel. We don't need to destroy it rather it should be managed in a way to convert its property in a beneficial way.

At now I just try to use this plant as a material of anaerobic bio-reactor to process liquid waste.

The International Institute of Tropical Agriculture (IITA), which headquarters is based in Ibadan, Nigeria developped two biological control agents—Neochetina and N. bruchi released after the water hyacinth in River Mono, Republic of Benin. Apparently the experience was also used in the victoria lake (east africa), and has been successful. May be you can contact them to know more about their biocontrol agents.

One has to be very careful about bio-control. Control agents from one should not be transferred to another region without extensive testing. Otherwise, what might seem to be a solution could become yet another problem. Cane toads in Australia is just one example of this.

Herbicide will work if applied directly to the plant via spraying but care must be taken to not also destroy desireable plants that are nearby. Mechnical or hand removal works well, it is much more time consuming of course. I have heard that it is used in some parts of the world as animal feed but have never witnessed that.

Water bodies that are infested with E.crassipus is to be assessed for identifying methods of control. In small water bodies such as ponds, it can be controlled by using phytophagous fishes. Clear the weeds once and stock with these fishes which will take care of the sprouting plants.

In large water bodies such as canals or channels, the infestation can be controlled by physical removal using some machines. Use of biological control agents such as weevils can be promoted in small fallow lands. However the effect of this agent is limited.

Change the salinity is yet another option, but needs to consider environmental safety.

Added to all above; the water hyacinth was used for various things like what said in the previous answers; besides all bio-polymer production also carried out with the plant. there are several ways to use the plant sp., instead of control through various chemical or biological means

Water hyacinth proliferation is directly linked with human activities in water bodies. Direct mixing of nutrient-rich domestic wastes, industrial effluents and agricultural runoff significantly contribute to the quick proliferation of waterhyacinth. So prevention of aquatic pollution is the first step to waterhyacinth management. Weedicies should not be used. It will cause other environmental issues. Biological control agents like waterhyacinth weevils (Neochetina bruchi and N. eichhorniae) are good candidates. They will reduce the growth and proliferation of waterhyacinth. Though biocontrol process is seemed to be slow, it is a sustainable method.

This is an interesting question with interesting answers. This water pollutant is really a menace to the environment of Lakes and rivers. The posed question requires careful research. One way of managing such plants is to find a way of using them economically so that they become raw materials as already explained above. Use of biological or chemical control methods may interfere with other aquatic species such as fishes and other water-loving creatures. Some research on this noxious plant has also indicated some possibility of using the weed in the manufacture of animal feeds. While not conclusive, research on economic uses of the plant is the better option (environmentally) for managing it.

Managing water hyacinth for other uses has other problems. The biomass is the major problem in tackling the water hyacinth. You can use the plant parts but the question is how to arrest its spread. Biocontrol coupled with phytoremediation is the best solution. Water should be purified at the discharge site itself through plants like Typha. All other methods will be effective only in paper

Water hyacynth can be effectively used in paper pulp industry. I recollect that someone asking me about a decade ago as how to grow more hyacynth. As long as the plant is not used it is a weed. Once you find an effective use it will be harvested so much that one does not find it anymore.

Thanks to members for some interesting submissions. As several recognise, Eichornia has redeeming features apart from its (obvious) beauty. One unmentioned early application was to create booby landing fields on lakes for Japanese aircraft during WWII.

More recently, the plant is being used on a small irrigation and fire contingency reservoir, 100s of metres away from the nearest river, in southern Portugal. Here this tropical aquatic tolerates winter water temperatures ca10ºC and thrives most of the year, flowering from Spring to Autumn. Apart from removing nutrients, helping to clear the water and, presumably, feeding the pond's fish, it is also harvested for composting.

But the plant may have another benefit. Has any evaluation been made of Eichornia crassipes transpiration? By shading the water and lowering its daytime temperature net evaporation may be reduced actually rendering the plant a conservation resource.

Comments welcome.

According to the litterature some insects (Neochetina spp) are used for biological control water hyacinth. Some herbicids are also used for the its control. Some fishes eat water hyacinth like Ctenopharyngo idella, Tilapia melanopleura and T. mossambica. Visit his link please

http://www.google.sn/?gws_rd=cr#fp=3c8832027f118af4&q=Eichornia+crassipes+et+insectes

Monitor the quality of water pollution is the reason for the rapid growth of vegetation

Antonio, i have not looked for any transpiration estimates (altho for this case it can be done easily in lysimeters). However, from an ecological perspective hyacinth can reduce sunlight penetration into lakes thereby totally changing the ecosystem, and if left unchecked, hastening the (natural) transition of a lake into a bog, starting from the lake margins where dead leaf buildup leads to other plants establishing and moving inwards.

Amartya,

Thank you for yesterday's thoughts:

> i have not looked for any transpiration estimates (altho for this case it can be done easily in lysimeters).

They actually sound rather complicated to me. But floating one in water may be less onerous than an excavation.

> However, from an ecological perspective hyacinth can reduce sunlight penetration into lakes thereby totally changing the ecosystem,..

Fair enough.

> ...and if left unchecked, hastening the (natural) transition of a lake into a bog, starting from the lake margins where dead leaf buildup leads to other plants establishing and moving inwards.

Yes, I completely understand. In this case, though, the pond's southern half is kept open. And, for all the life it harbours in what was previously a parched hillside, the thing is completely artificial.

I had not direct experience in water hyacinth managing but however I think that different solutions could be considered together in order to face such a problem.

Sure that the possibility to use this plants for compost is very interesting on condition that the cost is bearable enough.

The biomass is the major problem.Where will you get space for composting such an enormous bulk?

Hi Gunathilagaraj

If one viewed bulk-composting on the same scale as meeting the requirements for yet another asphalt carpark or a plastics factory, then finding the necessary space would be solved. But recycling projects are not top commercial ventures, as Luciano suggests.

That is the problem. Asian democracies may not be interested in composting. They are for factories, special economic zones and factories

Yes unfortunately the economic convenience in such situations could be crucial; but one could improve the techniques aiming to reduce costs; but also this direction of development is not cheap on my opinion. The topic appear actually very interesting.

the other problem apart from space (for composting) is drying.. water hyacinth stems have a very high water content. In Kolkata i have seen control happening on small scale, by people that remove small patches on a weekly basis, and spread that out to dry. depending on the weather, that can take a week if there's no rain.

Antonio, re: lysimeters, one simply scoops upo a water hyacinth mat into a tank (or large shallow drum) thats placed on a large weighing scale. One puts in a weighed amount of water in the once a day, and weighs the whole lysimeter, and then after 24 hours weighs againm before adding the next instalment of water. water difference = ET as there is no other input or output of water.

Yes Amartya, we too use this in Bangladesh...drying and then using for burning or composting water hyacinth. Helpful except in the rainy season...but then by the time rain comes most of the thick mats are gone to composting.

I agree with M.I Zuberi

Biological control by Neochetina bruchi (beetal ) is one of the method....

Amartya, thank you for the clear lysimeter explanation which I have only just spotted. I suppose one could use a smallish tank, or even a fruit box with a plastic sheet liner, and a standard human weighing machine to obtain a fair reading.

As for the bulk issue - thank you, Sandi, for the comment - shredding will reduce the volume and expedite decomposition.

I beg to disagree with Prof. Praveen.Tamot By biological control using beetel, you are introducing a new pest which apart from attacking water hyacynth may choose to attack other plants as well when there is shortage of water hyacynth. Best control measure is o find out a better use of this plant

An insect is recommended as a biocontrol agent after exhaustive feeding tests on several plant species. Insects that are specific to water hyacinth alone are recommended/released in biocontrol attempts.

I do agree that before using the biocontrol measures, the insect is screened. But in case of non availability of specific food the insect will definitely not die but try to get used to some other source. Life is always a struggle for existence.

I too agree on this point. But theoretically safeguards are usually taken in all classical biological control programmes.

Yes, I do agree that biocontrol can be useful...but it is suitable for cases where the item protected is comparatively valuable....has continuous and large populations to be worked by the control agent and some other aspects. Also it is expensive to provide the agent to the weed, need careful monitoring, there are associated danger to other related to the method. How ever, the point is if we have more suitable control measures like available to water hyacinth ...we think twice before decision making. This species is so widely dispersed....during flooding it spreads to all corners of the country in small patches and can survive all the seasons of the year.......transported widely..and so on. Other aspects..I don't want to discuss..now....can get much information from web pages.

Harvest it and use it as fertilizer.

Frank

Perhaps it can be utilised for producing biogas. There could be several posible uses which are yet to be explored.

Yes Andre, your lysimeter ideas sound workable and practical. I suppose the 'safest' way is manually harvesting and spreading them to dry, as whats being done (at least in eastern India and Bangladesh as mentioned by Zuberi). Shredding also sounds good like a value added process as that can accerelerate the drying process as mentioned. There is always some uncertainity with biocontrol, as pointed out by Andra and Zuberi. Water hyacinth is a south american plant, so there would not be any "native" insects in asia that would control this. There may be some other asian native beetle, i do not know, however as Andra points out, there are possibilties that the beetle can look for other food sources.. by the way, what part of the plant is targeted by this particular beetle Neochetina bruchi ?

Dried petiole is good fiber that is used for handicraft

Like the idea of using it to make fertilizer. Harvesting to make bio gas as well as paper might be alternate solutions but not sure of the economics. Use of herbicides like 2,4-d environmentally dangerous. Biological control as well as mechanical harvesting has less impact on the environment.

Amartya, you are generally right in asserting: "Water hyacinth is a south american plant, so there would not be any "native" insects in asia that would control this." I am no entomologist but, I do know that while some insects, like some of us, are set in their ways others, as Andra indicated, are enterprising and opportunistic. The Asian Red Palm Weevil, for example, will kill over 40spp of palms most of which are absent in its original habitat. Similarly, Argentine Paysandisia moth larvæ destroy European, Pacific island and other foreign flora. And, of course, no web-weaving spider, including your beautiful Argiopes, check the nationality of their next meal.

very true, Antonio, thanks for the examples ! And there lies the uncertainity inherent in biocontrol, in an introduced insect opportunistically consuming other species either at the same time or when populations of hyacinth have been herbivored down.

I wonder whether any experiments were conducted regarding absorption of toxic materials frow water bodies, especially Industrial wastes. I remember that at the National Botanical Research Institute some work was going on in this line but I am not aware whether this plant was tried. If it can absorb unwanted chemicals this can be used for scavenging and their removal from water bodies.

Yes Andra..there are many research results which indicated that water hyacinth can absorb/adsorb pollutants, heavy metals and organic pollutants and can be used as a remediation agent. One can get information from web sites...I have some papers.

As Dr. Zuberi indicated that this plant can be effectively used for scavenging industrai pollutants. So water hyacynth should not pose a problem at all. Nature provided this plant to us and we should use our wisdom to utilize it in a proper way.

In Egypt, water hyacinth is a regional problem and has a significant deleterious impacts on aquaculture, agriculture and human health. I proposed a research plan to control water hyacinth by harvesting the plants using a mechanical method, after which biochar as a safely fertilizer will be produced. The biochar is a promising alternative method which immobilizes heavy metals and removes organic pollutants during the pyrolysis process of plant residues. I am currently interested to have an international cooperation in this regards.

in Portugal is also a huge problem. Some continue to use it to clear grey waters, others to produce biogas and fertiliser but the real problem is the growth rate of these plants that can cover ponds and rivers in a few days affecting and damaging all economic activities. Here, is still a huge and great problem although it is completely forbidden to use or plant.

Recently I saw interesting case regarding Eichornia in a Large Beel in Rajbari District of Bangladesh.This perennial waterbody naturally maintaining mixed population of white and pink lotus(Nelumbo) and Eichhornia.People of adjacent regularly harvest huge amount of Eichhornia as Farm feed( for cows). They stated by their lifelong experience that cows produce much more milk if they are fed Eichhornia on regularly.

Yes, I imagine. Water hyacinth has an high water content which means that cows when feeding are taking also a great amount of water. It is well known that in dried periods cow produce less milk. In Portugal they used it to feed chickens also. The problem nowadays is that the growth net is so huge that is quite impossible a man harvest it.

Does anyone have table of nutrients? The release of N during processing indicates

amino acids and/or protein.

this is very interesting and I think that experiments may be designed to verify this validity

Don't have a table of nutrients but you expect moisture to be +90%, crude proteins

There are at least three insect biocontrol agents that can provide some control -

Waterhyacinth mite, Orthogalumna terebrantis

Waterhyacinth moth, Niphograpta albiguttalis

Waterhyacinth weevils, Neochetina eichhorniae and N. bruchi

Here are a couple of links of this and related work on controlling aquatic weeds using insects and arthropods.

http://www.ars.usda.gov/is/ar/archive/may96/hyac0596.pdf

http://www.ars.usda.gov/is/np/aquaticweeds/aquaticweeds.pdf

The radical solution do deal with invasive plants would be to collect specimens of the native plants and then eradicate all plants in a water body with herbicide. Once the herbicide has been washed out, you can re-plant the native species. Similar measures have been used in the US with invasive fish, using Rothenone (Fintrol) as sanitizing agent. Not pretty, but if you are desperate...

Now if somebody could find a way to deal with those pesky lionfish here in the Caribbean, that would help! The photo shows the situation about 2 years after we spotted the first one in our waters.

I agree with Randall. There are some studies with biocontrol and these are much prettier than the ones using herbicides. The most critical factor for this plant is temperature. Here in Portugal the cold winters , when they are real cold for following days, are sufficient to kill the plant. The problem is that it depends on the years and I do think that they adapt very fast.

In Nigeria and other west African countries, water hyacinth has been a recurrent problem. Adekunle AA and other workers at the University of Lagos have reported the potential use of the fungi Curvularia pallescens in conttrolling the weed.

Perhaps it can be used in paper pulp industry as one of the raw mayerialt

Here in central Florida water hyacinth can be a real problem since the growth rate is so high. In the past it got completely out of hand and made many water bodies impossible to use. An extremely aggressive program of herbicide application is the only thing that has kept them at a background level. A small amount of them seem to always survive the herbicide treatments and they are the agressive "seeds" for the next wave.

There has been some really interesting uses found for the plant and if there was only some way to curb it's growth rate it could be very good and useful. Unfortunately at the rate it multiplies in our climate here it seems we will always have some of it around. Of course it helps the plant spread when people think the flowers are pretty and they take it home with them.

Mechanical harvesting http://www.hrsc.org.za/history.htm and sustainable use of the end product https://www.youtube.com/watch?v=dWuzfTtvtaE&feature=youtu.be is the preferred method of control on the Hartebeespoort Dam, South Africa. Biological and chemical control is not currently recommended.