Lots of interesting news is getting buried at the moment, this one just managed to make it into the BBC headline spot. Two new weapons in the war against Japanese Knotweed. One is a psyllid, a plant louse; the other a leaf fungus. I can see the undoubted advantage of using a natural predator to control an out of control population and I can see an awful lot of research has gone into this to ensure that only Japanese Knotweed is the target. However my instinct says that even though it's unnatural and unhealthy to have an alien plant species with some of it's population controls missing, introducing further alien species into the equation might not be the best attempt at a solution. I'd be interested to hear others views - am I being a wildlife xenophobe?

Japanese Knotweed proposed agents

Hi Marigold. This concept must be welcomed by those who's land is often affected by japanese knotweed. Let's face it, it is a very nasty bit of plant weed here once it takes a hold, it is a right bugger to remove. Since it's roots can go three meters into the ground, no amount of digging, burning, weedkilling or chopping will get rid of them.
  There is an area only around the corner from my home which always gets covered by these evil plants. They could cover an acre of land in just literally weeks, one week it's all bare soil, then in the next it resembles a tropical rainforest.
  I've got a feeling that if we carry on having this run of mild winters, any problems involving Japanese knotweeds is only going to get worse.
  I know people are worried about using predators but it's probably the most natural and cleaniest way to remove pests (whether be it plants or insects) without the need for weedkiller and poison.
  After all, we at my workplace, release predators in the greenhouses as part of our ongoing battle against pests and it is proving to be the most effecient way in keeping unwanted pests in check. Once all them pests are eaten up, the predator's foodsource is dried up and the predators themselves die away since they won't eat anything else (bees, that kind of thing).
  Clever, all this nature lark.

I must admit I haven't been affected by this knotweed at all - doesn't seem to have reached here, but your description is quite alarming. I remembered you used biological control in your greenhouses - are they native species though? That was the bit that was concerning me, introducing predators not native to the UK.

Some context

http://news.bbc.co.uk/1/hi/sci/tech/7574102.stm

 

We have the bright red 'lily devourer' in our garden where it eats the stargazer lillies.

http://news.bbc.co.uk/1/hi/sci/tech/7573530.stm

Beware!

A cold winter is only way to kill them off.

Marigold:

Lots of interesting news is getting buried at the moment, this one just managed to make it into the BBC headline spot. Two new weapons in the war against Japanese Knotweed. One is a psyllid, a plant louse; the other a leaf fungus. I can see the undoubted advantage of using a natural predator to control an out of control population and I can see an awful lot of research has gone into this to ensure that only Japanese Knotweed is the target. However my instinct says that even though it's unnatural and unhealthy to have an alien plant species with some of it's population controls missing, introducing further alien species into the equation might not be the best attempt at a solution. I'd be interested to hear others views - am I being a wildlife xenophobe?

Japanese Knotweed proposed agents

 

Interesting thread - it is like the parable of the old lady who swallowed a fly. Humans have unbalanced fragile eco-systems all over the world, including grey squirrel, cray fish and mink at large in this country, rabbits and cane toads in Australia and so on. Unfortunately,  to rebalance, sometimes introducing more alien species (the natural predators) is the only solution

I like the Old Lady analogy - I'd been thinking of I Am Legend where what seemed like a brilliant solution soon became an amazing disaster. The inference that we are maybe somewhat lax at preventing the accidental import of alien species, in the links from Ulric and Duane, is very interesting.

Marigold:

I like the Old Lady analogy - I'd been thinking of I Am Legend where what seemed like a brilliant solution soon became an amazing disaster. The inference that we are maybe somewhat lax at preventing the accidental import of alien species, in the links from Ulric and Duane, is very interesting.

Ive been looking through a few web pages to see if,during warmer periods in the past we've had the same trouble from alien species as presently.No luck as yet,but i think it would be interesting to see if this situation arose before and how it was delt with.If i come across any I'll report.

There was a piece on the radio this morning about a population of Chinese Mitten Crabs meeting American Signal Crayfish, these species are trying to occupy a very similar niche so are likely to conflict.  Some eminent ecologist suggesting that the Chinese crab would “win” on the basis of being more aggressive.  (BBC article on a different tab of Marigolds original link).  One of the other points made was that these creatures cause damage to riverbanks as well as wiping out other species.

 

Up here neither species is a problem yet, although there is significant vigilance about signal crayfish and the Environment Agency run periodic campaigns to remind fishermen of the risks of spreading disease through dirty tackle.

 You most often find evidence of White Clawed crayfish where otters feed (very neat) or where goosander have dinned (very messy).  Otters have done a good job of removing mink released/ escaped from fur farms, which allows water voles back into catchments. I wonder of Otters eat either of these aliens?  

I saw a documentary yesterday about wildlife in Darwin, Australia and the devestating effects of the Cane Toad, an 'alien' species, which is rapidly spreading across the country, wiping out many rare creatures.  They are extremely toxic, and kill the animals that may prey on them:

http://www.wwf.org.au/ourwork/invasives/canetoad/