Japanese Knotweed

Scientists are looking at biological control of Japanese knotweed in the UK.

A tiny Japanese insect that could help the fight against an aggressive superweed has been given the go-ahead for a trial release in England.

Since Japanese knotweed was introduced to the UK it has rapidly spread, and the plant currently costs over £150m a year to control and clear.

But scientists say a natural predator in the weed’s native home of Japan could also help to control it here.

The insect will initially be released in a handful of sites this spring.

Which sounds all fine and dandy. In Japan, knotweed is kept under control by natural predators. Having no such predators in the UK, it spreads quickly and destructively.

They looked at the superweed’s natural predators – nearly 200 species of plant-eating insects and about 40 species of fungi – with the aim of finding one with an appetite for Japanese knotweed and little else.

It’s the “and little else” that bothers me. That suggests “not exclusively” and when released into an alien environment, what, I wonder, will they develop a taste for? This one has unintended consequences written all over it.

8 Comments

  1. And what, prey tell, is going to be the local natural predator for this non-local insect when the populations of *it* start getting out of control and they, after a while of getting bored of knotweed, start eating other stuff?

    Idiots.
    .-= My last blog ..Why let drink decide? =-.

  2. That’s the question, isn’t it? What other plants might this insect take to once exposed to it? Hence my reference to unexpected consequences.

  3. I saw the report in the news and was rather surprised when the body administering the trial stated that it was all OK because they had tested the bug on around 200 knotweed-like plants which were not affected at all. Thats only a few thousand non-knotweed-like plants they haven’t tested then!

  4. Well, they’ve only been testing this plant-hopper and probably a few dozen other likely candidates for the last decade or so, so what do these scientists know?

    The answer is, a bloody damn sight more than most armchair theorists do! Everybody’s heard of the Cane Toad fiasco, the problems with polynesian rats (they finished off the dodo, BTW, not hunting by people. Dodos tasted absolutely appalling, apparently), introduced insects and so on.

    This is the point of the testing, to determine if the plant hoppers are specific enough to knotweed that they can be released without causing trouble or pest problems. Word is, they don’t. They’re some of the millions of highly host-specific insects out there that don’t run riot because they’re co-evolved into a relationship with one species of host plant that they like, and won’t move off.

  5. And of course, scientists are never wrong and never make mistakes, so I’ll trust them implicitly.

    How many plant species are there in Britain? Thousands? Tens of thousands? How can anyone be sure that an alien insect won’t develop a taste for a new species of plant – particularly if its usual fare is no longer available? You cannot. No one can, no matter how much testing went before. It’s how evolution works, organisms adapt or die.

    Introducing an alien species is a really bad idea. I don’t need a white coat to be able to figure that one out so the “armchair theorist” thing doesn’t wash with me, I’m afraid. And, no, I don’t revere scientists as they’ve been far too willing to pull the wool over our eyes of late. Climate science anyone?

    Scientists have a great deal of work to do to earn our trust back. Expect it to take a while. Although, to be fair, probably not as long as it will newspaper reporters and politicians 😉

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