Insect could halt spread of superweed


Scientists tackling the thorny problem of a foreign superweed hope a humble insect could halt its rampage across the UK's gardens.

The sap-sucking psyllid is the natural enemy of the invading Japanese knotweed, which has spread rapidly across our towns and countryside.

If the tiny insect was introduced here, it would be the first time the process of biocontrol has been used to control a plant species in Europe.

Little did the Victorians know that when they introduced Japanese knotweed as an expensive ornamental plant, it would prove the bane of horticulturists more than a century later.

With no natural enemies in the UK and an ability to grow up to three metres in as many months, the weed has flourished unhindered, even affecting the 2012 Olympics site.

Just tiny fragments of the plant can form new shrubs, tearing through tarmac, so the uprooted weeds must be classed as controlled waste.

But scientists at CABI, a not-for-profit environmental research organisation, hope they have found a sustainable solution - which depends on introducing another species alien to our shores.

They identified more than 200 of the weed's natural enemies and rejected all but two which were highly-specific to the plant: the Mycosphaerella leafspot fungus, which devastates knotweed in its native Japan, and the tiny 2mm-long psyllid Aphalara itadori, which drinks its sap.

Neither are found in the UK, but scientists believe that if introduced they would bring down Japanese knotweed numbers and would not be able to feed on other plants.

Once out in the wild, the new species would sustain itself, so long-term control would be "effectively free" in comparison to the £1.56bn bill a Defra working group put on controlling the weed's spread using traditional methods, mainly chemicals.

Progress is currently further ahead with the psyllid, due to difficulties caused by the fungus' complicated life-cycle.

Dr Dick Shaw, who led CABI's research, said: "In the case of Japanese knotweed doing nothing is not an option, so we are applying a century-old technique to a new target and are very hopeful of an effective and sustainable outcome.

"Though it is more famous for its concrete-cracking ability, Japanese knotweed's impacts on our natural habitats are severe, crowding out native plants and seriously reducing opportunities for our native wildlife."

Researchers have been carrying out extensive safety testing under quarantine conditions, following strict international protocols, he said.

They plan to avoid a repeat of the notorious instance when attempts to biocontrol beetles in Australia went disastrously awry, flooding the country with poisonous Cane Toads.

The ugly amphibians were introduced in 1935 by the sugar cane industry in a bid to control pest beetles, but the carnivorous toads ate anything small enough to be swallowed and exploded in number.

For that reason, CABI scientists have been testing the Japanese knotweed's enemies against 79 plant species related to the weed, to make sure the natural controls will target only the knotweed.

Dr Shaw said: "Of course our priority is safety and that is why we have spent the last five years safety-testing the agents, so that we do not have a repeat of the infamous Cane Toad debacle which went ahead against the recommendations of scientists at the time."

CABI has been working to stop the spread of Japanese knotweed with funding from a consortium of sponsors: British Waterways, Cornwall County Council, Defra, the Environment Agency, Network Rail, South West Regional Development Agency and the Welsh Assembly Government.

Have you tried new the Independent Digital Edition apps?
Arts and Entertainment
On set of the Secret Cinema's Back to the Future event
filmBut why were Back to the Future screenings cancelled?
Susan Sarandon described David Bowie as
peopleSusan Sarandon reveals more on her David Bowie romance
Lewis Hamilton walks back to the pit lane with his Mercedes burning in the background
Formula 1
Arts and Entertainment
The new characters were announced yesterday at San Diego Comic Con
comic-con 2014
Arsenal supporters gather for a recent ‘fan party’ in New Jersey
Arts and Entertainment
No Devotion's Geoff Rickly and Stuart Richardson
musicReview: No Devotion, O2 Academy Islington, London
newsComedy club forced to apologise as maggots eating a dead pigeon fall out of air-conditioning
Life and Style
Balmain's autumn/winter 2014 campaign, shot by Mario Sorrenti and featuring Binx Walton, Cara Delevingne, Jourdan Dunn, Ysaunny Brito, Issa Lish and Kayla Scott
fashionHow Olivier Rousteing is revitalising the house of Balmain
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
iJobs Job Widget
iJobs General

BI Developer - Sheffield - £35,000 ~ £40,000 DOE

£35000 - £40000 per annum + competitive: Progressive Recruitment: My client is...

Employment Solicitor

Highly Competitive Salary: Austen Lloyd: MANCHESTER - Senior Employment Solici...

Senior Risk Manager - Banking - London - £650

£600 - £650 per day: Orgtel: Conduct Risk Liaison Manager - Banking - London -...

Commercial Litigation Associate

Highly Attractive Package: Austen Lloyd: CITY - COMMERCIAL LITIGATION - GLOBAL...

Day In a Page

Best comedians: How the professionals go about their funny business, from Sarah Millican to Marcus Brigstocke

Best comedians: How the professionals go about their funny business

For all those wanting to know how stand-ups keep standing, here are some of the best moments
Jokes on Hollywood: 'With comedy film audiences shrinking, it’s time to move on'

Jokes on Hollywood

With comedy film audiences shrinking, it’s time to move on
Edinburgh Fringe 2014: The comedy highlights, from Bridget Christie to Jack Dee

Edinburgh Fringe 2014

The comedy highlights, from Bridget Christie to Jack Dee
Evan Davis: The BBC’s wolf in sheep’s clothing to take over at Newsnight

The BBC’s wolf in sheep’s clothing

What will Evan Davis be like on Newsnight?
Finding the names for America’s shame: What happens to the immigrants crossing the US-Mexico border without documents who never make it past the Arizona desert?

Finding the names for America’s shame

The immigrants crossing the US-Mexico border without documents who never make it past the Arizona desert
Inside a church for Born Again Christians: Speaking to God in a Manchester multiplex

Inside a church for Born Again Christians

As Britain's Anglican church struggles to establish its modern identity, one branch of Christianity is booming
Rihanna, Kim Kardashian and me: How Olivier Rousteing is revitalising the house of Balmain

Olivier Rousteing is revitalising the house of Balmain

Parisian couturier Pierre Balmain made his name dressing the mid-century jet set. Today, Olivier Rousteing – heir to the house Pierre built – is celebrating their 21st-century equivalents. The result? Nothing short of Balmania
Cancer, cardiac arrest, HIV and homelessness - and he's only 39

Incredible survival story of David Tovey

Tovey went from cooking for the Queen to rifling through bins for his supper. His is a startling story of endurance against the odds – and of a social safety net failing at every turn
Backhanders, bribery and abuses of power have soared in China as economy surges

Bribery and abuses of power soar in China

The bribery is fuelled by the surge in China's economy but the rules of corruption are subtle and unspoken, finds Evan Osnos, as he learns the dark arts from a master
Commonwealth Games 2014: Highland terriers stole the show at the opening ceremony

Highland terriers steal the show at opening ceremony

Gillian Orr explores why a dog loved by film stars and presidents is finally having its day
German art world rocked as artists use renowned fat sculpture to distil schnapps

Brewing the fat from artwork angers widow of sculptor

Part of Joseph Beuys' 1982 sculpture 'Fettecke' used to distil schnapps
BBC's The Secret History of Our Streets reveals a fascinating window into Britain's past

BBC takes viewers back down memory lane

The Secret History of Our Streets, which returns with three films looking at Scottish streets, is the inverse of Benefits Street - delivering warmth instead of cynicism
Joe, film review: Nicolas Cage delivers an astonishing performance in low budget drama

Nicolas Cage shines in low-budget drama Joe

Cage plays an ex-con in David Gordon Green's independent drama, which has been adapted from a novel by Larry Brown
How to make your own gourmet ice lollies, granitas, slushy cocktails and frozen yoghurt

Make your own ice lollies and frozen yoghurt

Think outside the cool box for this summer's tempting frozen treats
Ford Fiesta is UK's most popular car of all-time, with sales topping 4.1 million since 1976

Fiesta is UK's most popular car of all-time

Sales have topped 4.1 million since 1976. To celebrate this milestone, four Independent writers recall their Fiestas with pride