South American weevils released in UK waterways to tackle invasive weed

[Alan de Enfield]

South American weevils released in UK waterways to tackle invasive weed | Invasive species | The Guardian

 

‘Wonder weevil’ takes on pennywort weed in the battle for clear rivers (telegraph.co.uk)

 

South American weevils have been released into Britain’s waterways by the government in order to tackle the invasive species floating pennywort.

The industrious bugs are being heralded as a hope to cut back the weed, which grows rapidly and blankets rivers and canals, drowning out the light and choking the life within.

 

Floating pennywort was brought over from North America as an ornamental plant. It can grow up to 20cm a day, forming dense rafts over rivers that are not only detrimental to biodiversity but disrupt recreational activities such as fishing and canoeing, and exacerbate flood risk.

It is highly unusual to release non-native species into the wild to tackle invasive species, and this is the first time biocontrol has been used to tackle pennywort.

 

When asked whether the release couldturn into an old-woman-who-swallowed-a-fly situation, with the weevils later needing to be controlled, officials assured the Guardian that there had been a decade of tests into the safety of the release. The government has also stressed that releases of weevils are strictly controlled, and require a licence from the Environment Agency.

Richard Benyon, the minister for biosecurity, said: “It is important that we tackle invasive non-native species to protect our native plants and animals and safeguard our environment, economy and health.

“We all have a role to play in stopping the destruction caused by floating pennywort – and the release of the South American weevil will boost our efforts to eradicate this pest from our waterways once and for all.”

 

The releases were carried out during the winter, with more planned for this summer. Since 2011, the Centre for Agriculture and Bioscience International (CABI), with Defra funding, has been investigating the potential use of a biocontrol agent for floating pennywort. They found that Listronotus elongatus were effective at removing it as they laid eggs on and ate the plant. The larvae also eat into the stems, reducing its ability to grow.

Djamila Djeddour, a senior scientific officer at CABI, said: “Following years of extensive research into the potential biocontrol of floating pennywort, we are pleased and excited to have released the weevil into the wild. Field studies by CABI scientists and collaborators in South America found this weevil to be the most promising agent and after comprehensive screening in CABI’s quarantine facility in the UK, it was confirmed to be highly specialised, only feeding and developing on this damaging weed.

“Further releases will begin later this year, supported by a range of sponsors, and the weevil’s impact, establishment and spread will be closely monitored.”

[Jen-in-Wellies]

Here is a picture of one out of the water, with a couple of humans for scale. Should get rid of the floating pennywort in quick time.

By Bigthink.com, Fair use, https://en.wikipedia.org/w/index.php?curid=69257408

[billS]

 

I wonder what unintended consequence this is going to have?

[Alan de Enfield]

7 minutes ago, billS said:

 

I wonder what unintended consequence this is going to have?

 

 

Absolutely none (the experts say)

[Arthur Marshall]

Sufficient unto the day is the weevil thereof.

[Puffling]

Any creature that has EVIL as part of its name shouldn't be trusted near the waterways.

[Naughty Cal]

They released weevils into the Witham a while back now to deal with the weed.

 

They made not a jot of difference!!

[Alan de Enfield]

3 minutes ago, Naughty Cal said:

They released weevils into the Witham a while back now to deal with the weed.

 

They made not a jot of difference!!

 

 

They just wobbled but they didn't fall down.

[tree monkey]

When I was newly released into the world I worked in a small private estate with a rather wonderful late Victorian greenhouse, anyway the boss was big of the standard chemical pesticides, including nicotine shreds and after a few goes at setting these off, with the associated streaming eyes and racking cough and the realisation that all they did is make the whitefly into 40 a day smokers, I pushed hard for biological pest control.

 

After a few stumbles they worked well, we worked with a biological control supply company and they helped us massively and let us buy much smaller amounts than their normal big commercial buyers.

 

We used all sorts but the big one was Encarsia for the whitefly, the big idea was they couldn't survive our winters so any escapes would never breed outside, which is a fairly common way of control for the introduced predator.

I was a happy monkey, untill I spotted the outdoor colony of Encarsia just outside the greenhouse door that had happily survived the winter.

 

Anyway all the above waffle is to make the point, biological control a great idea but potential to further bugger up an already buggered system, let's hope this one works as it should

 

 

 

 

 

[Hudds Lad]

Because introducing foreign species into our ecosystem has worked so well in the past and never has unintended consequences. 🙄

 

@Jen-in-Wellies will you be sacking off the boat and riding a Shai-Hulud down the cut then?  

[Jen-in-Wellies]

1 minute ago, Hudds Lad said:

@Jen-in-Wellies will you be sacking off the boat and riding a Shai-Hulud down the cut then?  

That's the plan.

[Slim]

1 hour ago, Alan de Enfield said:

 

 

Absolutely none (the experts say)

It will all end in tears 😢 

[Chris Lowe]

7 minutes ago, Jen-in-Wellies said:

That's the plan.

You need to find a blacksmith to make the riding hooks first

[doratheexplorer]

What could possibly go wrong?  It's not like introduced species have ever caused any problems have they?

 

 

55 minutes ago, tree monkey said:

When I was newly released into the world I worked in a small private estate with a rather wonderful late Victorian greenhouse, anyway the boss was big of the standard chemical pesticides, including nicotine shreds and after a few goes at setting these off, with the associated streaming eyes and racking cough and the realisation that all they did is make the whitefly into 40 a day smokers, I pushed hard for biological pest control.

 

After a few stumbles they worked well, we worked with a biological control supply company and they helped us massively and let us buy much smaller amounts than their normal big commercial buyers.

 

We used all sorts but the big one was Encarsia for the whitefly, the big idea was they couldn't survive our winters so any escapes would never breed outside, which is a fairly common way of control for the introduced predator.

I was a happy monkey, untill I spotted the outdoor colony of Encarsia just outside the greenhouse door that had happily survived the winter.

 

Anyway all the above waffle is to make the point, biological control a great idea but potential to further bugger up an already buggered system, let's hope this one works as it should

 

 

 

 

 

Same idea:

 

 

[tree monkey]

18 minutes ago, doratheexplorer said:

What could possibly go wrong?  It's not like introduced species have ever caused any problems have they?

 

 

Same idea:

 

 

 

It can work and it does work, I'm just a tad cautious, the realty is most glasshouse crops in the UK and probably most of the world use some sort of biological control.

 

[doratheexplorer]

2 minutes ago, tree monkey said:

 

It can work and it does work, I'm just a tad cautious, the realty is most glasshouse crops in the UK and probably most of the world use some sort of biological control.

 

Yes, I've used them before in controlled environments like glasshouses.  Pennywort control isn't like that.  History has many examples of well-meaning introductions which have gone horribly wrong.  Just ask an Austrialian about cane toads.  The problem is that the natural environment is almost infinitely complex so trying to predict every possible outcome is impossible.  There's zero chance that anyone can be 100% certain that the release of these weevils won't cause unforeseen problems.

[Jen-in-Wellies]

44 minutes ago, buccaneer66 said:

You need to find a blacksmith to make the riding hooks first

Was thinking of Calder & Hebble hand spikes.

[Hudds Lad]

8 minutes ago, Jen-in-Wellies said:

Was thinking of Calder & Hebble hand spikes.

Finally, a safer use for those Bargee Bill Weed Cutters  

Edited May 17, 2022 by Hudds Lad

[tree monkey]

30 minutes ago, doratheexplorer said:

Yes, I've used them before in controlled environments like glasshouses.  Pennywort control isn't like that.  History has many examples of well-meaning introductions which have gone horribly wrong.  Just ask an Austrialian about cane toads.  The problem is that the natural environment is almost infinitely complex so trying to predict every possible outcome is impossible.  There's zero chance that anyone can be 100% certain that the release of these weevils won't cause unforeseen problems.

Yup, that's what makes me nervous, the same complexity that fascinates me also makes this sort of thing dodgy as he'll, the cane toad thing is a classic example of unforseen consequences 

[MtB]

42 minutes ago, doratheexplorer said:

There's zero chance that anyone can be 100% certain that the release of these weevils won't cause unforeseen problems.

 

 

To paraphrase richard benyon:

 

"I don't foresee any unforeseen problems".

 

 

Oh, the overconfidence of the technically incompetent politician. Not that there is any other sort. 

 

 

[IanD]

48 minutes ago, doratheexplorer said:

Yes, I've used them before in controlled environments like glasshouses.  Pennywort control isn't like that.  History has many examples of well-meaning introductions which have gone horribly wrong.  Just ask an Austrialian about cane toads.  The problem is that the natural environment is almost infinitely complex so trying to predict every possible outcome is impossible.  There's zero chance that anyone can be 100% certain that the release of these weevils won't cause unforeseen problems.

The trouble is that it's impossible to prove a negative, such as "the weevils won't cause a problem" -- insist that something "must be 100% safe" and the end result is that you can never try *any* new solution out... 😞

 

You have to balance the small (very small, the experts say...) chance of the weevils causing a problem in the future against the 100% guaranteed chance that pennywort is causing a problem now, to which we don't have a solution...

[tree monkey]

15 minutes ago, IanD said:

The trouble is that it's impossible to prove a negative, such as "the weevils won't cause a problem" -- insist that something "must be 100% safe" and the end result is that you can never try *any* new solution out... 😞

 

You have to balance the small (very small, the experts say...) chance of the weevils causing a problem in the future against the 100% guaranteed chance that pennywort is causing a problem now, to which we don't have a solution...

And didn't forget the fear of chemicals,  which means any sort of chemical treatment is out

[Hudds Lad]

16 minutes ago, IanD said:

to which we don't have a solution..

Well, we do, it’s just not a cheap one.

[IanD]

1 minute ago, tree monkey said:

And didn't forget the fear of chemicals,  which means any sort of chemical treatment is out

Can't we kill off the pennywort using nooculer radiation instead of chemicals? Or maybe Putin will do it for free... 😉

1 minute ago, Hudds Lad said:

Well, we do, it’s just not a cheap one.

So it's not a solution then, if CART doesn't have the money... 😉

 

(what is it, anyway -- thousands of little men with nets?)

[Moke]

If they just released the smallest ones and kept all the larger ones locked away would that be the lesser of two evils ?  (Say it out loud)