Grasshoppers versus water hyacinths in South Africa | Global Ideas
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- Опубліковано 9 тра 2022
- For some, the water hyacinth is an ornamental plant, for others a green plague. The Amazon native grows so fast it can overtake entire bodies of water and devastate whole ecosystems. Now experts have found an insect remedy for the problem.
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This stuff totally clogged a little manmade lake at the apartment where I lived in Houston. The frogs were deafening every night. It was really interesting how the water hyacinth took over so quickly. It made the lake gross and sludgy, until it all got taken out by maintenance.
The issue isn’t whether you’re testing that they only eat the hyacinths, the issue is what are the millions of grasshoppers going to eat after more hyacinths are depleted to an extent where they can no longer sustain the new grasshopper population? They’re so small and numerous, I’m struggling to imagine a controllable and effective/efficient predator that could control their population size.
The insects increae and decline with the water hyacinth. The practicve of biological control has been ongoing for over 100 years in South Africa without ever having a host-switch. We test these insects very carefully because we know that many successful introductions can be overcome by one bad one.
Megamelus scutellaris should never move to a different species.
The explosion of water hyacinth is due to high nitrogen waste water released into the lake. It soaks up the excess nutrient so it needs to be removed from the water because when it rots it releases more nutrient into the water. Using grasshopper may look like it’s working, but rotting hyacinth will just cause high BOD in the water. Best way is to reduce fertilizer run off and sewage release into the lake and use harvesting boats to remove the hyacinth and compost it and fix the removed nutrient into the soil.
I used to grow up close to the Hartebeespoort dam (in Rustenburg). The plant has caused quite an ecological disaster. Such a beautiful lake with some of the most beautiful mountain ranges. Just a pitty about those damn plants.
What nobody wants to talk about, is the levels of raw sewage being dumped into the rivers that feed Hartbeespoort dam. That is what causes the Hyacinth to grow out of control. There are used nappies, used female hygiene products, raw sewage. All washing into these rivers. Until that is addressed, the Hyacinth will keep growing.
@an enigma , do you have any direct knowledge of the area? My farm is a few km from this septic tank. When you have seen the scope of the problem, then come tell me again.
All that nitrogen will fuel toxic algal bloom downstream later. But they push their problem away for now.
You are right, most of this pollution is coming from Johannesburg, it really exacerbate the plants growth
This could be the the earths way of cleaning itself through the plants I hope the grasshoppers don’t get out-of-control🤷🏾♀️
Eutrophication is the single biggest factor leading to outbreaks of water hyacinth and the pollution is the biggest concern, with water hyacinth (and other invasive macrophytes) being a symptom of failing wastewater treatment infrastructure. Hartbeespoort Dam is one of the most polluted dams in Africa which is why water hyacinth recovers so quickly and covers the dam early in the spring time until the biological control agent populations are big enough to suppress it again.
For anyone thinking phytoremediation: no, the water hyacinth cannot remove enough of the nutrients to make even a blip of difference in a dam the size of Hartbeespoort. This has been tested and published by water quality experts (see Curtis and Carroll 2021) :)
Water hyacinth can also be viewed and appreciated as beautiful and useful. See the appreciative videos showing the beautiful flowers and foliage. I especially enjoy watching the time lapse videos of the blossoming.
The plant is economically valuable as well. In Vietnsm, for example, there are whole industries around utilizing the plant. One industry, or set of industries, is woven home decor. Examples include beautiful, intricate baskets, hampers, planters, storage and organization containers. They can be left a natural, warm light golden brown color, or dyed in a variety of other colors. They are beautiful.
Very interesting work.
The problem is that as soon as a single plant can be seen growing in our dams action needs to be taken immediately. There are thousands of poele visiting these dams for fiahing every year and if each of those with boats can remove what ever they can wel also get the job done allot quicker
great news,thanks !
hey DW, planthoppers are not grasshoppers. as far as insects go, they are very highly unrelated (different orders). you should have people in charge of reports like this who know better than to just change the names of species like that...
Good info, and agreed about expertise being needed for good reporting.
Agree entirely. We provided the information for this clip (and were interviewed in it) and I am not sure how this happened!
Benjamin Miller I looked it up, it seems like there also are projects experimenting with using an odd aquatic grasshopper species against water hyacinths. whoever weote the script for DW must have accidentally mixed up the grasshoppers with the planthoppers.
@@Ass_of_Amalek you must have found Cornops aquaticum. Awesome insect, super damaging to water hyacinth but never established well in South Africa.
You might be correct - who knows?
Anyway, thank you all for your engagement with this topic and helping us to get the correct information to you. It has been enjoyable going through the comments!
A terrific juggernaut of a solution: thanks for this..🎈📌
I have seen a few videos where water bodies are covered up to reduce evaporation, and this seems like the perfect solution, but for a different problem.
Thanks for the interesting video DW.
Water hyacinth increases water loss due to evapotranspiration. It is not a good solution at all.
won't plants lose more water because of transpiration than evaporation would have ?
I don't know why this video is disliked so much, I thought it was quite informative.
Inanda Dam needs this
We have the same problem in Manila
Because you are allowing untreated sewage into your water way.
Kerala have have same problem.
Hopefully this will help!
Harvest the plants for soil improvement.
😂😂 i was at the dam last weekend and it was 90% covered with this plant
What an opportunity to harvest compost! Throwing it away.
This has been tried. It doesn't work so well becasue the plant accumulates heavy metals from the water. How do you feel about mercury in your veggies? :)
@@benjaminmiller9463 do people eat the fish there? Reading about the plant, when heavy metals are present, the roots have the greatest uptake of the metals compared to leaves and stems. Examination of the plants for toxicity would be a good idea, if clean then they are compost!
@@benjaminmiller9463 Sounds like most of the uptook metals are stabilized by composting, made unavailable for plant uptake.
Concentration and speciation of heavy metals during water hyacinth composting
The Tessier sequential extraction method was employed to investigate the changes in heavy metals speciation (Zn, Cu, Mn, Fe, Pb, Ni, Cd and Cr) during water hyacinth (Eichhornia crassipes) composting. Results showed that, the contents of total metals concentration were increased during the composting process. The largest proportion of metals was found in the residual fraction which was in more stable form and is consequently considered unavailable for plant uptake. Reducible and oxidizable fractions of Ni, Pb and Cd were not found in all trials during water hyacinth composting. The concentrations of Cu and Cd were very low comparative to the other metals, but the percentage of exchangeable and carbonate fractions were similar as other metals. From this study it can be concluded that the appropriate proportion of cattle manure addition (Trial 4) significantly reduced the mobile and easily available fractions (exchangeable and carbonate fractions) during the composting process.
@@rustyyb8450 there are people composting already. But it’s not a suitable management practice, they can’t remove enough biomass. It’s also expensive, as sometime the wind will blow the biomass to the other side of the dam moving it away from the composting machinery.
People do eat the fish, mostly in low income households without much better options. I’m not aware of the health implications of this as it is not my study area. I’m sure there is literature on this.
Yes some invasive water plant some imbacile ruined the Hartebeespoort dam it was a dam crystal clear you could dive in it and enjoy the scenery I can confirm that the hyacinth exists
I ended up here because I wanna know if I can have this plant in my aquaponic system or not. I’m in South Africa.
this is SOOOOO risky, I wonder how they are today
SOLUTION ? : "In northern Brazil, and southern Venezuela, there are rodents called capybaras, that live in the Amazon River basin," Kembel wrote. "They are the largest rodents in the world, and can be the size of a pig. ... These furry creatures eat water hyacinth as the main part of their diets.
Yes I have seen that on national geographic...I think we need to get about 300 capybaras and control the breeding house for this area. It will be beneficial. Thanks for the advice and information.
They are not host specific herbivores, so their introduction will be dangerous to other plant species that they might find more tasty ;)
We have capybara and water hyacinth that have taken over our river. The capybara do not enough water hyacinth to do any damage to the plants population.
Maybe it can be a resource opportunity?
Yes, many commercial products can made from water hyacinths.
What you saw represents a fortune to be made. Though you lacked knowledge you have some wisdom. Ethanol, methane, acetone, starch, starch syrup, sorbitol, glue, paint, cardboard. Ponder on these products.
So.... they form dense mats. Then why not cut around one of the large carpets and then pull the whole floating carpet onto a conveyor system reaching into the body of water?
The mats move with the wind. They are also enormously heavy and that kind of machinery is expensive
Harvest it for compost to promote growing food.
One would think the plant could be used as a support system to keep water from evaporation. The plant shades the water and helps keep it clean.
But by blocking the surface it reduces the oxygen in the water.
@@guy7gsa agreed. It definitely makes the water sludgy and anaerobic.
no, these INCREASE evaporation because the surface of the plants is bigger than the water surface and evaporates water uninhibited because as a freshwater plant, it doesn't need to save water. the covering of the water surface causes problems because it not only prevents other plants lower down from growing due to lack of light, but it prevents oxygenation of the water because the hyacinths absorb CO2 from and release O2 into the air, whereas underwater plants do that in the water. meanwhile the dead parts of hyacinths sink to the bottom and decompose there, causing yet more oxygen depletion. the slowing of water flow and shielding of wind at the surface also reduces the rate of water exchange between the surface and the lower levels of the body of water, which further prevents the oxygenation from the air at the surface from benefiting the water down lower. thus water hyacinths dramatically reduce the amount of underwater plants a body of water can support by blocking the light, and dramatically reduce the amount of animals it can support by lowering oxygen levels.
water hyacinth has permanently open stomata, thus INCREASES water loss from evapotranspiration. The negative impacts of water hyacinth vastly outweigh any benefits, if any exist at all.
Your statement is very reasonable. However, reason is in short supply in SA.
So they are sure the hopper would not feed on any other plant in the area? Were the tests finished?
The tests had to be concluded prior to the insect being released with applications made to several government bodies to approve the release. This insect has also been tested in the USA where it was also approved independently.
No, they are not. See how much wisdom they have?
Careful what insects you introduce , might get out of hand and breed another headache.
This practice is not a new thing and has been on going worldwide for over 100 years. The science behind introducing biocontrol agents is incredibly rigorous and the responsibility of introducing an effective and safe insect is not taken lightly. We are 100% satisfied with the specificity of Megamelus scutellaris and I have no doubts about it's safety.
@@benjaminmiller9463 Again wisdom has called you, but you shut the door out on her.
It’s a good idea but in the past introducing another species into a different environment has ended up becoming a nuisance of their own.
could they use them to make floating beds to grow food on it like they do in Bangladesh?
Yes, but why not floating islands called Chinampas a did the ancient Aztecs of Mexico City. Their system of agriculture assure a surplus to run an empire for hundreds of years.
Use water hycinth to produce fuel and fertiliser its a resource and while it also purifying water at the same time if it chocking dams use barrier to direct these water hycinth to fuel production plant. while at the same time make affords to prevent pollution from leaking to lake and use the same water hycinth in the ppllited water that is leaking in river to purify that water also
Why not build a swimming harvesting machine?
Water hyacinth grows too fast and it's too costly. These have been tried and failed all over Africa at enormous expense to developing nations.
do these hoppers harm other water species like paddy ?
No, it is host-specific
Thanks very well done. How is the population of the grasshoppers regulated? Are they self regulating when the food runs out the reduce in numbers , they move onto other food or are they eaten by some of the local species?
Yeah, the trick is to hope one of your native species wants to eat the invasive insect. You're basically introducing a new strand to your food web.
Hi Kevin, I have worked on this project for some years now and was interviewed on this documentary. I am not sure why they called our insect a grasshopper, as it is nothing of the sort bnut that is neither here nor there.
To answer your question. the planthoppers, and all biocontrol agents, are self-regulating in that, as the population of the target weeds declines, so do the insects. They are host-specific and cannot feed or reproduce on other plants. This is why we don't aim to eradicate the water hyacinth (which is impossible anyway), as the insects will always reside to some extent on the remaining plants.
Spiders, fish, and a native wasp species have all been found to feed on the planthopper and they do not cause any toxic effects to these predators or parasitoids.
If you collected it and mulched it up and fed it into a bio digester it would be an amazing natural solar collector providing energy and fertility.. too late now you have introduced the hopper..
The water content and heavy metal accumulation is too high. We have thought of this already :)
Can't these things be used to make biogas?
No, you are thinking of Taco Bell...
Yes, biogas, ethanol, and fertilizer.
My father was a scientist, well done to our South African scientists.
don't grasshoppers become locusts when they became too densely packed?
I believe grasshoppers and locusts are two separate but similar animals.
@@lwilton I'm just here to help- they're insects, not animals.
DW is reporting badly. these are planthoppers, which are highly unrelated to grasshoppers.
@@GRJproductionz wow, you are clueless. Insects are also grouped as animals. That's like saying dogs are mammals not animals, or a shark is a fish not an animal. 🙄
agreed. I work on this insect, it is a planthopper, not a grasshopper. More closely related to aphids and stinkbugs than a locust.
Look at all that free goat food. this could feed so much livestock if its compressed to make sylidge
Not only goats but, chickens, pigs, cows, sheep, camels, horses, donkeys, rabbits,etc.
They use water hyacinth as chicken food in Malawi
The are good for cows, goats, chickens, pigs
Pike would eat frog's,ducks and chicken's would maybe eat insects
Lol, I misread " pike would eat frogs, ducks.and children's"!
Folks, the grasshoppers don't eat other plants now because they have they hyacinth...they will begin eating other plants once those are gone. Bad idea.
Not true. In stress experiments the insects wouldn't even feed on closely related species. The literature on this is published in the public domain.
how many african faces do you see in this video....i am not a robot
life will find a way.... the hoppers could evolve, the plants also....
Not true. These insects have co-evolved with the plants for millions of generations without a host shift in their native environment where water hyacinth is less plentiful than in invaded areas. Why would it change now?
@@benjaminmiller9463 they they don't know what they'll be eating 100-200 years from now... Everything evolves all the takes is one minor mutation beneficial or not, thank you again for your support and I appreciate hearing your opinion. Peace.
@@julianaponte827 fair enough. I would like to state openly that, as a researcher on this project, I know that they will not evolve a host shift. They need very specialised conditions for oviposition and feeding. But, I appreciate your comments and interest all the same. (Additionally, neither I nor my research group profit from the release of these insects, so that isn’t a motivation for a conflict of interest in case anyone was wondering if that influenced my responses)
So they’re working on releasing a grasshopper plague on their country. Did they check if the grasshoppers would eat another native and agricultural species ? It reminds me of Australia.
Grasshoppers is not a problem for us, we always had swarms here, we know how to decimate it
They said in the video that they did thorough testing to ensure that the grasshoppers are host specific and won't continue to destroy native species and crops. 2:05
DW is reporting badly. they're planthoppers, not grasshoppers. those are highly untelated insects, and planthoppers tend to be very selective in what plants they feed on, whereas grasshoppers tend to eat a huge range of plants as long as they don't contain some very particular toxins. the DW reporters seem to have just stupidly plastered over the term "planthopper" that they didn't know with the term "grasshopper" that they did know in their minds without ever googling it. 🙄
The video used the wrong word. This is a planthopper not a grasshopper
Here is the solution - use machines to harvest the weed. Job done.
They have tried that in the past. The plant grew faster than they can remove it woth the machine.
@@ArnoSnyman007 Build bigger machines. Harvest the weed for animal feed or fuel.
@@WJKF easier said than done. Remember it is still Africa after all. It might be easy in the first world to just splash out enormous amount of money, not so much in a small municipality in North West, South Africa.
@@ArnoSnyman007 True. Yet it still might be an opportunity though. Maybe it could be viable to create weed farms to quickly grow a lot of biomass?
@@WJKF That is a bad idea. Utilising water hyacinth is what has made it the world's worst aquatic invasive plant.
Guys we've already made these mistakes
Import some hippos
I think south africa probably has hippos.
We defninitely have hippos here. I have photographs from my research of hippos in miles of water hyacinth. They don't really like to eat it.
DW 2030: Grasshopper plagues and how can we overcome it.
TARDED!
This is absolute waste & risking disease introduction. Why not use them as fodder?
Using water hyacinth as fodder is not recommended because it picks up heavy metals from the water. It is also mostly water, so the cost of extracting enough biomass to feed animals is not cost effective.
There is far more threat of disease from the polluted water than from the introduction of a safe, scientifically tested biological control agent
Hope this answered some of your concerns. Reach out if you have more questions.
@@benjaminmiller9463 why are the heavy metals in a fresh water lake meant for human drinking?
@@estebancorral5151 They aren't. In fact, that's exactly the concern I am trying to raise. However, trying to treat the problem at the reservoir is not a) possible, even with a massive cover of these plants, and b) the smartest option. Treating heavy metal pollution at the source is more likely to have success than once it is already in the system. The problem is not whether or not we should introduce the world's worst aquatic weed to address a nutrient problem. How do we foster the political will to get the people in power to address nutrient pollution BEFORE it's in the dam?
Despite the fact that there is a massive body of evidence showing that water hyacinth can sequester pollutants and heavy metals from water, they fail to show that the plants can have a significant effect on reducing these pollutants on a significant scale on large water bodies. In fact, there is evidence from the dam in question in this video that, even with 100% water hyacinth cover, the effect of the weeds on total pollution is negligible.
in short - water hyacinth picks up enough heavy metals to make it poor food for livestock. Water hyacinth does not pick up enough to make any difference to large dams or lakes.
@@benjaminmiller9463 you asked a political question. Lake Lucerne in Switzerland was declared clean after tough environmental laws were enacted and enforced. It takes a disciplined population for good laws to bear fruit. Commenter Kamilla was pointing that in her unique style, and you owe her an apology
@@estebancorral5151 I believe I answered that question in fairness and with sufficient evidence. I am not here to be offensive. Furthermore, It is not fair for you to decide if another person should take offence to my response. In addition, I am not sure who commenter Kamilla is, since I have been sharing dialogue with you - so I am rather confused by your comment.
Also, the Lake Lucerne example that you have mentioned (although, I admit I don't know anything about it) speaks to the point I am trying to make EXACTLY.
Political will + a disciplined and involved citizenry = results. No propagating of an invasive species to "clean up" required. We are on the same page with that.
I am happy to share all the information that I have with you on a fair basis. All I want is for people to understand the basis of this project is as a pro-environment and low-cost alternative to herbicide spraying, but please don't expect me to engage in a petty argument in the comments section.
This is plant from South America? how did it get here, and who brought it over? for what?These locusts will only bring other problems, you cannot accurately determine the impact these locust will have on the rest of our fragile ecosystem. This is very naive, ecosystem take 1000's of years( maybe a helluva lot more)to attain homeostasis, this won't end well guys, it never has when we interfere, please can we learn from our mistakes.The only way to remove this plant is physical removing, while this may be too expensive and a logistical nightmare, it's the only solution.
Bio-weapon
South Africa is one of the worst places on Earth. They have not enough resources, especially, water for the current population. 100 years life in big South African cities was relatively safe and prosperous for that time, but not now.
Do you live in South Africa? If not, please be careful of these types of opinions. Our country has its issues, but our people are resilient and friendly. Anyone who has been here will usually agree. I recommend you visit :)
@@benjaminmiller9463 you are ignoring the issues and Kamilla is right. Truth and justice is not the forte of South Africa.