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Friday, July 24, 2009

Those dodgy immigrants

This morning's Western Mail reports that Welsh Government officials are considering whether to grant a licence to release a non-native tiny sap-sucking insect into Wales to tackle Japanese Knotweed, which has caused millions of pounds of damage to buildings, roads and railways. A formal consultation was launched yesterday on plans to introduce foreign “jumping plant lice” to tackle the rampant vegetation.

The paper says that the highly invasive weed (Reynoutria japonica) was brought to Britain from the Far East by Victorian explorers and introduced as an ornamental plant in the early 19th century, though the alternative story is that it was introduced to stabilise railway embankments and spread along the route of tracks.

They say that the weed soon showed its true colours, bursting from manicured gardens as an unstoppable pest, its stems able to break through concrete, tarmac and brick. Even when chopped into bits, tiny parts of the Japanese knotweed can turn themselves into whole new plants. It is in fact illegal to remove any part of the plant from the site where it is growing.

There is though another story, namely that the plant behaved differently in the British climate than it did in Japan. That in itself must offer a cautionary tale as to how the Japanese jumping plant louse, or psyllid will react to its new surroundings. As the paper illustrates there are plenty of other examples of species introduced to another climate for a specific purpose only to become a pest itself.

I have a particular interest in this as Swansea is one of the worst affected parts of Britain with regards to Japanese Knotweed, its total biomass is now said to exceed 62,000 tonnes. The costs of a national eradication plan through conventional means has been estimated at a staggering £1.56bn by the Department for Environment, Food and Rural Affairs. Swansea's share of that cost is beyond the financial resources of the local Council.

Professor Paul Brain, from the zoology department at Swansea University, says "Psyllids are already causing problems in Ireland where they were introduced so there are concerns that the parasite might attack other UK plants. I think a lot more research should be done."

The list of alien parasite experiments which went wrong include:

Killer snails (Euglandina rosea) were introduced to Hawaii to control the giant African land snail but they started attacking native snails too

the cane toad, brought in by Australian farmers to control the cane beetle, spread rapidly, killing animals who tried to attack them

the mongoose, introduced to Hawaii to keep down rat numbers, soon found it much easier to dine on birds’ eggs instead.

Scientists have, however, successfully used Trichogramma ostriniae, a small wasp, to control the European corn borer which devoured high value crops in the US.

And the cactus moth has been used successfully in Australia to control the prickly pear cactus.

Meanwhile, the Sun reports on another troublesome immigrant. They say that Britain is being invaded by killer chipmunks. We are told that the animals, who are described as vicious, disease-riddled rodents, have escaped or been released into the wild by traders or domestic owners terrified of infection. In addition the UK is apparently on high alert in case a wave of the vermin, which have wreaked havoc in France, pours through the Channel Tunnel.

The chipmunks are an ideal target for The Sun because of their promiscuity. The females can have up to 16 babies a year, so the population will be growing fairly rapidly. If they could claim benefits then the story would amount to a 'perfect storm' for the paper.

The threat is not to be taken lightly however, the Siberian chipmunks - Tamias Sibiricus - may have Lyme disease, which targets the nervous system and can be fatal for humans, and even rabies:

Tony Mitchell-Jones, of Natural England, said: "Animals not native here, like chipmunks, can have a devastating impact on our own species if they are released into the wild.

"They compete for food and can sometimes carry diseases that native wildlife cannot fight off."

Northern France has been hit by a plague of chipmunks, whose numbers have exploded to 100,000 since just 17 were freed from a Brussels park in 1980.

Naturalist Guy Bruel told how the cunning critters have dug a network of tunnels to avoid a cull. He said: "Their trench systems are amazing - like something out of the First World War.

"Efforts have been made to poison or even shoot them, but they always get away."

There are fears UK tourists will slip chipmunks into rucksacks or car boots and bring them across the Channel undetected.

There are lessons to be learned here including around the introduction of the psyllid to tackle knotweed.
> Reynoutria
or Fallopia
considerable more research must be done..maybe hire one of the shetland isles and have a trial run over five years
What will eat the Jumping Plant Louse?

Can Japanese Know Weed be used for anything, perhaps as a fuel, when dried, used to make paper perhaps, once it has a commercial value, people and companies may start harvesting it?

Regarding Killer Chipmunks, Chip and Dale have a lot to answer for!
Peter, you may recall the Welsh Lib Dems have a polciy on Japanese Knotweed that we passed a few conferences ago. I think we are still the only political party to have one actually
Do you know, I had forgotten that. Did it involve dodgy insects? Remind me what it said.
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