Japanese Knotweed versus Aphalara itadori

[sometimes]

BBC NEWS | Science & Environment | Predators could be superweed fix

[sometimes]

I'm in two minds about this. On the one hand knotweed is a real pain, on the other I'm not happy about introduction of a pest. Have we not seen disastrous examples in other 'solutions'?

[handyman]

Hello Sometimes, must say I agree with you there.

It seems to be a British qwerk, that after creating the problem, be it Japanese Knotweed, Rhoddedrons or Signal Crayfish, et al, we always look for the cheapest or easiest way to eradicate it, usually with spectacular failure.

I cannot understand the logic of introducing another foreigner to our shores, if it is dependent on the original problem for its survival. All they can ever hope for is to control the problem rather than eradicate it.

In the case of Japanese Knotweed, as this has thrived and colonized much of the UK, in contrast to how it grows in its home country, by introducing this beetle, is it not likely to thrive as it has an unlimited food source?

It took me seven years to eradicate Japanese Knotweed from my garden, I just wish my neighbours were as conscientious! They are quite tolerant of my forays into their gardens to dig out roots and burn them.

Handyman

[sometimes]

I can see that areas of knotweed growth will become no-go areas because of clouds of flying beasties.
The research seems to concentrate on the relationship between Knotweed and Aphalara itadori. But what about our native species that might feed on Aphalara itadori - is it poisoness to them? Will they be a welcome food source for warblers? Answers of 'I don't know.' would mean we shouldn't do it.

[Rob_D]

You are worrying needlessly about introducing this new beetle. If it causes problems then we can just introduce something like a Cane Toad to eat it

Sadly it seems there are no easy answers. I am just hoping that one day we'll develop a really effective and foolproof solution to invaders (GM bacteria or Fungus perhaps?). Well done to Handyman for your efforts though.

[sometimes]

Originally Posted by Rob_D

You are worrying needlessly about introducing this new beetle. If it causes problems then we can just introduce something like a Cane Toad to eat it .

I think the song goes "" I know an old lady who swallowed a fly""

[tcvarlh]

True and look how the song ends
Why by all that's holy do we try to cure a problem be slapping a worse idea across it like a poultice?
What eats these psyllids? Do we have a predator here?

[Lancashire Lad]

The scientists say they have tested the beetle's feeding preferences on several "important" British food plants etc. and are satisfied that the insect will only go for the Knotweed.

However, they have not tested the insect's preferences on ALL British plants, so at best, they can only put this arguement forward as hypothesis based on incomplete data.

Even if these insects do prefer Knotweed, and manage to decimate it. (Presumably their numbers would have multiplied into the millions to achieve such a feat). What happens then?

Do all these insects conveniently die off? or do they turn their attention to whatever other British native plants take their fancy?

I remain entirely unconvinced of any merit in this proposal.

Regards
Mike.

[PMG]

Of course once they have eaten all the knotweed they are going to turn their tiny toes up and die for their country - job done and there again maybe they will discover a taste for ?wheat ?British orchids ?any and all home grown vegetables..... ?roses .......... grass??........Hmmmm.......

Pauline

[RobSutton]

Originally Posted by Lancashire Lad

The scientists say they have tested the beetle's ..........

It isn't actually a beetle but as someone higher up the thread has already mentioned it's a Psyllid. These are sap sucking insects and most are generally very host specific. This makes it a lot less likely to switch to other food sources than some other herbivorous insects. Could be it's the lesser of two evils, very hard to know until it's tried.

[Lancashire Lad]

Originally Posted by RobSutton

...It isn't actually a beetle but as someone higher up the thread has already mentioned it's a Psyllid...

Can't find Psyllid mentioned higher up the thread, but I can find two mentions of beetle. (Handyman & Rob_D).

Anyway, Beetle - Psyllid - Insect, whatever. Call it what you may, it is still a non indiginous species, over which these scientists will have no control whatsoever, should it be introduced.

You say it would be less likely to switch to other food sources. Hmmm, maybe so, but what when it gets hungry after eating all the Knotweed.

One would have thought that the scientists would be falling over themselves to point out the fact that the insect would die off once its Knotweed food supply was depleted. I wonder why they aren't.

I take on board the gist of your reply, but remain unconvinced.

Regards
Mike.

Edit - Have just spotted Psyllid in tcvarlh's reply. (Still wouldn't have known it wasn't a beetle though. ).

[tcvarlh]

I'm getting a bit worried about this 'bug' Aphalara itadori or Shinji as our japanese friends call it. I find a mass of hype and 'spin' about the good it will do and the effectiveness in destroying Japanese Knotweed Fallopia japonica, BUT, almost no literature concerning the natural predators of the 2mm long 'vampire bug' (Contract Journal quote)
Why is it so awkward to get both sides of this story? It may be the Japanese have reams of data, I can't read Hanji/Nippon.
Do we use the standard British answer to our problems, Do it then worry about the effects? Of course we do. These cute little BUGgers have relatives that make tomato growers lives very miserable...
Deliberately introducing a foreign or alien specie seems an insanity. Is there an island somewhere infested with FJ we could try the cure out. I wager the test site will be somewhere akin to the Vale of Evesham. Hope you folks like Spanish greenhouse tomatoes!!
tcvarlh [/font]

[RobSutton]

Originally Posted by Lancashire Lad

Can't find Psyllid mentioned higher up the thread, but I can find two mentions of beetle. (Handyman & Rob_D).

Anyway, Beetle - Psyllid - Insect, whatever. Call it what you may, it is still a non indiginous species, over which these scientists will have no control whatsoever, should it be introduced.

You say it would be less likely to switch to other food sources. Hmmm, maybe so, but what when it gets hungry after eating all the Knotweed.

One would have thought that the scientists would be falling over themselves to point out the fact that the insect would die off once its Knotweed food supply was depleted. I wonder why they aren't.

I take on board the gist of your reply, but remain unconvinced.

Regards
Mike.

Edit - Have just spotted Psyllid in tcvarlh's reply. (Still wouldn't have known it wasn't a beetle though. ).

I don't think they would expect eradication of the knotweed just that the psyllid would weaken it and make it easier for other plants to compete with it and therefore make it less aggressive in its spread. If the knotweed doesn't disappear then there will always be a population of psyllids around to keep it in check and as the host plant is always around then why would the psyllid need to find something else to feed on?

It would, of course, have been much better if the knotweed hadn't been introduced in the first place. It has though, and it is a serious problem and this insect may help. There are risks but the research seems to have been pretty thorough.

[RobSutton]

Originally Posted by tcvarlh

I'm getting a bit worried about this 'bug' Aphalara itadori or Shinji as our japanese friends call it. I find a mass of hype and 'spin' about the good it will do and the effectiveness in destroying Japanese Knotweed Fallopia japonica, BUT, almost no literature concerning the natural predators of the 2mm long 'vampire bug' (Contract Journal quote)
Why is it so awkward to get both sides of this story? It may be the Japanese have reams of data, I can't read Hanji/Nippon.
Do we use the standard British answer to our problems, Do it then worry about the effects? Of course we do. These cute little BUGgers have relatives that make tomato growers lives very miserable...
Deliberately introducing a foreign or alien specie seems an insanity. Is there an island somewhere infested with FJ we could try the cure out. I wager the test site will be somewhere akin to the Vale of Evesham. Hope you folks like Spanish greenhouse tomatoes!!
tcvarlh [/font]

I must admit I don't think the original BBC article referred to by Sometimes could really be called a "mass of hype and spin", it seems a simple straightforward report. Are there other articles you have been looking at or are you just applying your own "hype and spin"?

[sometimes]

Two additional considerations
Mutation is not advantagous in it's native land, but it might be here if the mutation opens new food sources.
The knotweed is not a food source in the UK(?) - presumably other 'beasties' find it unpalatable. Unpalatable means poisonous. The Aphalara may concentrate this 'poison' and make it readily available for creatures further up the food chain.

[Hobjob]

I share people's natural caution, but my reading of the situation is that this plan has been very carefully researched - and in today's scientific world we are a bit wiser than we were, though not all knowing

A Psyllid has been used successfully, in combination with the chochineal insect, to largely eradicate the prickly pear problem of Southern Africa.

When I worked in the rural areas there 35 years ago it was a rampant pest, now it is only seen in isolated clumps.

[Adam Cheeseman]

Originally Posted by Lancashire Lad

Hmmm, maybe so, but what when it gets hungry after eating all the Knotweed.

Perhaps the salient question should be; "In its natural range of distribution, are there any plants other than Fallopia japonica that this particular Psyllid feeds on?"

If the answer is yes then the next question should be; "Do these plants, or relations in the same family, occur in the wild in Britain?"

I expect these questions have been asked in so many words.

Cheers,

Adam

[Adam Cheeseman]

Of course, the obvious answer is to rally the masses of the WI jam makers as Fj, when it is young, is edible for humans, being akin in taste/texture to Rhubarb. Knotweed Crumble and Custard anyone?

Cheers,

Adam

[sometimes]

Sorry but I couldn't resist, Adam.......

Are you trying to wind us up?

[Hornbeam Hedge]

I think he's being serious

Free food in your yard - edible weeds! | Wise Bread

[RobSutton]

Originally Posted by Adam Cheeseman

Perhaps the salient question should be; "In its natural range of distribution, are there any plants other than Fallopia japonica that this particular Psyllid feeds on?"

If the answer is yes then the next question should be; "Do these plants, or relations in the same family, occur in the wild in Britain?"

I expect these questions have been asked in so many words.

Cheers,

Adam

These questions are being asked by the Advisory Committee on Releases to the Environment (ACRE) who were asked to consider the Aphalara release in July of this year. A summary of the questions they are asking is at:

ACRE - Advisory Committee on Releases to the Environment - Meetings

I think Adams idea of mobilising the WI would be a superbly ground-breaking example of biological control that merits serious consideration

[sometimes]

Originally Posted by Hornbeam Hedge

I think he's being serious

Wind as in gas? never mind, it's been one of those days.

[Lancashire Lad]

Originally Posted by RobSutton

...These questions are being asked by the Advisory Committee on Releases to the Environment (ACRE)...

Rob, there is some interesting information here. I thought it worthwhile to post the relevant ACRE extract below.

Extract below from: -MINUTES OF THE 118th MEETING OF ACRE AT JESUS COLLEGE, OXFORD, THURSDAY 3rd JULY 2008

10. Application to release the non-native psyllid Aphalara itadori for the classical biocontrol of Japanese knotweed (Fallopia japonica var. Japonica). ACRE/08/P14
Defra (CSL) has received an application for a licence to release the non-native psyllid Aphalara itadori under Section 16 of the Wildlife and Countryside Act 1981 (WCA). The applicant wishes to release the psyllid for the classical biological control of Japanese knotweed (Fallopia japonica var. japonica), a non-native species in the UK which is restricted under the WCA. If approved, this would be the first classical biological control programme against a weed species in the UK. Section 14 of the WCA prohibits the release into the wild of any animal which is ‘of a kind not ordinarily resident in and is not a regular visitor to Great Britain in a wild state’. Derogation from Section 14 can be obtained through the issuing of a licence under Section 16 of the Act, dependent upon the outcome of an assessment of the risks and potential benefits of release of the organism. Defra is responsible for the issuing of these licences for England and asked ACRE for its advice on the risks posed to human health and the environment by this release.

ACRE members discussed the application and supporting evidence at length, together with the consultation group’s comments and the applicant’s response to these. The committee recognised the potential value of a biological control agent for Japanese knotweed, and the need to very carefully balance the potential risks versus the potential benefits were acknowledged. Having considered the application, ACRE concluded that insufficient information had been provided to enable the members to support licensing the release of Aphalara itadori at this stage. The committee’s comments fell into three key areas:

i) Behaviour of the psyllid outside of its native environment: ACRE recognised that excellent work had been done in demonstrating the limited host range of the psyllid, which provided confidence that it is essentially monophagous. Members were concerned, however, at the lack of information provided as to the likely impact of the psyllid if it were to be released. In particular, whether it could reach sufficiently high densities to have an effect on the Japanese knotweed populations, and what might be the indirect effects of these levels of the psyllid? The applicant had explored the issue of parasito