Thursday, 25 March 2010


A couple of auriculas: Left, 'Sirius,' right, 'Robbo.'

Now then. Gosh and begorrah! I think it's time for a bit of thought on Alien Invasions.

I'm sure you are aware, as we all are, of the threat posed by invasive alien species. Naturalist Edward O Wilson, his website is here, lists five main causes of extinction which you can remember with the mnemonic HIPPO:

H = habitat loss
I = invasive alien species
P = pollution
P = population growth
O = over-harvesting, of natural resources.

Alien species are responsible for horrendous extinction problems in the UK. The antipodean Crassula helmsii for example, is wrecking lakeland habitats; Himalayan balsam, Impatiens glandulifera harms our water courses by smothering natives and of course, we have the Victorian plant collectors to thank for the more widespread scourge, Japanese Knotweed.

More recently, the harlequin ladybird, Harmonia axyridis, a thug from Asia introduced to Europe, apparently, AS A BIOLOGICAL CONTROL, has established itself comfortably in Britain and looks set to eat the population of native ladybirds, and then move on to a large range of insects.

Keep that little point in mind, if you kindly would.

Now then. I heard recently, about another alien species, Aphalara itadori, a plant-sucking psyllid which will destroy the Japanese Knotweed. And DEFRA, in its wisdom and sound judgment, is to release this into the wild.

Anything coming from that monstrous megaministry fills me with fear and loathing. It was they who cocked up the payments to farmers, thereby incurring a hefty fine from Brussels which we taxpayer had to pay. You can see earlier rude comments about this horrendous Government Department here.

That gives me serious misgivings. DEFRA says the psyllid has been tested on important British food plants. Oh? So that's all right then. No worries there. Ah, but what about the rest of the British flora? And what about our garden flora?

The only important British food plant I can think of, which is related to knotweed, is rhubarb, so I hope they've tested it on that, in particular.

And what about the many, superb Persicarias which we grow in our gardens? Will this psyllid munch into our native wild bistort? Will it ruin Persicaria affine, or the magnificent, rat tail flowered Persicaria amplexicaulis? Gawd, I hope not!!

And what happens if (?when) this species makes a tiny genetic shift and produces youngsters which like other genera? What then. A beet sucking psyllid on the way? A potato psyllid? Probably not, but you never know!

One of the main reasons given for not using genetically modified crops, in the UK, was the danger of 'modified genes' getting into the wild. Nobody managed to explain how that could happen, but it was still pedalled as an argument for banning them 'A Pandora's box,' we were told, 'and once it's out, there's no putting it back.

Persicaria polymorpha
will it succumb to the psyllid introduced to zap Jap. knotweed?

Well, it's exactly the same with this damned psyllid. You can let it go, but you can't control it and you certainly can't get it back. Thinking you can do so is about a daft as believing you could re-capture and destroy all the harlequin ladybirds. Or as stupid as trying to cull badgers, thinking that will cure Bovine TB - and that - Welsh Assembly please note - in the face of scientific evidence showing that attempting to cull them causes perturbation which actually increases, the spread and risk of TB.

Alien species, released for 'natural' pest control have been disastrous in many parts of the world: cane toads in Australia, Mongooses in the Caribbean and Mauritius and Harlequin ladybirds are all strong examples. I just hope Aphalara itadori doesn't turn out to be as disastrous.

That knotweed again, Persicaria polymorpha, in close-up.
It's too pretty to lose and completely harmless.

I'm listening to Thomas 'Fats' Waller performing Your Feet's Too Big!

This day in 2006 I made a mini-pond with an old white Belfast sink and some rocks. Today, it has frogspawn - most of which I must remove so that the few tadpoles left behind have a chance of developing.

This week's film was Michael Haneke's superb Das weisse Band - Eine deutsche Kindergeschichte. (The White Ribbon.) Set in the last years before the Great War, this gave us a portrait of a near-feudal, German rural community following, in particular, the lives of the children. The oppression, at all levels, provided the driving energy for the narrative which unfolded amid enchanting scenery, all shot in black and white. The child actors were remarkable and the outcome not really as down beat as it could have been. An absolute masterpiece of cinema. Do watch it, if you haven't already seen it.

Auf wiedersehen


  1. Have you written to Defra? I heard this story on the radio last week and similar concerns about the introduction of one species to "deal with" another sprang to mind, based on long forgotten case studies from Uni days. As loathsome as Knotweed is, we have to hope the control doesn't turn out to be worse. Oh gloom.

  2. We first saw the harlequin beetle last year, don't know where or how it got into my US garden. It destroyed all brassicas first, then went for the dahlias. That was a declaration of war, and they were picked off one by one and squished between thumb and forefinger, gloved. We will be ready this year, not realizing they were bad bugs and allowing them to grow and multiply last year. Hope your government does not go ahead with their plan. There is always an unexpected turn with those things.

  3. I love Fats Wallers' Your Feet's too Big :-) - as to the content of your mail, canetoads always come to mind when I read about these so-called solutions to our man-made problems. But do they ever learn? Nah.

  4. I'm so glad you did this post, your reaction was exactly the same as mine when I first heard about this but as no one else was commenting i assumed as a mere amateur gardener that I didnt know what I was talking out.

  5. Ah, "Your Feets Too Big" My theme song!!
    You don't get girly size Nines!!!

    Harlequin Bugs, Flatworms, Knotweed, Equisetum

  6. I had a bit of heated debate with Geoff Hodge over at his blog when the intention was announced last year.

    As a scientist I'd like to think the research is at least adequate, but I fear the ever dwindling horticultural research funds available (I'm hopping mad over the proposed closure of HRI Wellesbourne for instance) might not stretch enough for this kind of thing.

    I do hope we don't have the same kind of problem as what's happened with the introduction of the Cane Toad in Oz, but that nightmare scenario immediately sprang to mind.

    I'm about to trial a commercial biological control method and initially I was feeling guilty that I might be employing double standards. I then realised that these are pest control methods which work via artificially boosting a naturally occuring predator population rather than using an alien species as in the case of the psyllid.

  7. BTW I believe Japanese Knotweed is edible as is Himalayan Balsam, perhaps we ought to be getting our celebrity chefs to dream up some tempting dishes using these weeds as the main ingredients. Then we could try and eat our way out of the problem!

  8. Good points, VP. As for Wellesbourne - don't get me started! Successive governments have stifled primary research in applied sciences in Britain since before Thatcher. I remember getting into a nasty row with a particularly poisonous and ignorant Merchant Banker at a dinner party in the early 1980s when the National Seed Development Organisation came under the axe. His premise was that primary research was a waste of time and money - and that R&D could all be left to commerce. And to think that our then PM read Chemistry at Oxford!

  9. Re - funding cuts - too true :(

    It was a trip to Wellesbourne in 1976 and finding they were interested in my proposed A level biology project looking at the effects of insecticides on plants which set me off in the direction of studying Agricultural and Environmental Science at Uni.

    On graduation I was interviewed for a research post at the Hill Farming Research Organisation (now gone), but was told at my interview the funding for the post was no longer there. So I'm a victim of those very cuts you've talked about here.

    We still pass HRI Wellesbourne every time we travel oop t'North to see family. I shall be really sad when we go past and don't see the lights on in the greenhouses.

    I can't believe that governments don't see the folly of relying on applied research being carried out in the commercial sector. Where's the objectivity and unbiased approach? Now I see the subsidy for FE colleges is being cut which will probably impact on affordable horticultural training just when the nation needs it most. Utter madness!