Knotweed - A New Strategy for Control

I found this article today. Trials using a non-native predator are being commenced.

http://news.bbc.co.uk/1/hi/sci/tech/8555378.stm

 

It makes me worried introducing non-native predators to tackle things like knotweed, the knotweed is non-native and look at how invasive it is, could we end up next year with these predators eating things we don't want them to. I bet the agrochem firms are looking at insecticides to kill these non-natives just in case a market appears.

 

What happens when the predator finishes with the knotweed - will it move on to eat something else instead? I haven't read the article in full, so if the answer is in there, apologies!

 

I had the same thought. Suppose the introduced preditor finds some native plant it prefers to knotweed?

Half these so called "experts" look as if they're about eleven, these days.

 

There are millions of non natives in this country, I doubt one more will make any difference.

Seriously though I know of clumps of Knotweed and they dont seem to have increased in size for years, I think the problems are now appearing where it was once planted, and they are trying to concrete it over, due to building everywhere.

One place in particular I know of where it was probably originally planted in gardens back in 'god know when', is now being built on and the struggle to kill it has been going on for a couple of years now.

It seems to me that its the "asbestos" of the plant world, I'd much prefer a clump of that in my garden as opposed to bind weed.

 

I am sorry i didn't read the full BBC artical i just skimmed over it, however having now read the full text i am deeply disturbed.
Quote

" After testing their candidates on 90 different UK plant species, including plants closely related to Japanese knotweed such as bindweeds and important crops and ornamental species, they discovered a psyllid called Aphalara itadori was the best control agent. "
(link in dave w post)

OMG we have slightly more than 90 species in the uk, 90 would not even cover all the arable crops grown in the uk so thats disregarding garden plants etc, etc, etc

Would the goverment release a new medicine after it being tested on 90 candidates i think not, and i tell you now they wouldn't approve a new pesticide under the same conditions.

...:skp:

 

According to the slot they gave it on TV this morning, it will be trialled in a 'secret' location somewhere and if successsful it still wouldn't be intoroduced nationwide for a some years.

 

One of the things on the BBC site that grabbed me most was the animated map showing the spread of Knotweed from 1890 to 1900.
It appears, as Strongylodon has pointed out, that experiments with the introduction of predators will be strictly controlled.
And as far as what will happen when the predators prey has been devoured, what usually happens is that the population of the predators is reduced. However there is always the possibilty of 'adaption' taking place where the predator changes its habits (diet in this case) to adapt to its evironment.
The UK is full of non-native flora and fauna and even the term 'non-native' depends on how far back in history one wants to go. Rabbits are as alien here as they are in Australia, but we tend to regard them as idigenous because they arrived with the Romans (or Normans) but in Oz they are regarded as a non-idigenous pest because settlers from the UK introduced them a couple of hundred years ago.

Climate change is already causing the arrival of previously non-native insects but given the change in climate these insects are in an environment that is natural to them. How we cope with the new arrivals is dependent on the species and upon our willingness to adapt to accommodate them and/or what steps we take to moderate their impact. Personally, going from what I've read and understand, the long term solution is to adapt.

 

Its a very interesting subject Dave - thanks for raising it.

I take great comfort to note that it is only being trialed in restricted locations. I presume all the insects have been given strict instructions not to fly off into other areas. :D

 

So maybe we should adapt, and just accept knotweed as native, bearing in mind its a matter of how far back you want to go Dave.

Ask the Aussies what they think about cane toads.

 

I was not suggesting we accept knotweed as native Pete.

I did say the LONG TERM solution MAY be adaption - and there are a lot of diverse processes involved in this, and did not rule out attempts at moderation i.e the introduction of non-indigenous predators.

As far as our antipodean pals are concerned, I'd imagine they regard cane toads just as unwelcome immigrants as the nice fluffy bunnies we sent them :D

What I was trying (and obviously failed) to do was to show that the question of 'native' v ' non-native' is a very complex issue and open for debate. As is the 'adaption/moderation' equation.

An associated issue is the re-introduction of indigenous fauna that have become extinct in the UK, e.g. wolves, beavers, wild boar, white tailed eagles and others. Lots of 'opions' and some scientific research and data. You read the research and make up your own mind. I'm still thinking!!!

 

I would agree that the question of native and non native is a complex issue. I suspect that it all comes down to time. Knotweed has no native predators now, but it could be that over the next 2000 years some will emerge.

Perhaps we just need to be patient. :D

 

Ok Dave, yes, whats native and what isn't is complicated and probably something you can never get to the bottom of.

I'm not sure we sent the Aussies rabbits, I think its more a case that, they took them out there themselves.
But then we are back to who is the native population yet again, and how many years constitutes being native.