Gardening: How do you fight slime-trailing pests?

Scientists are on the trail of more environmentally-friendly ways of killing slugs. Helen Lewis reports

An essential gardener's weapon is threatened with extinction. For years the dedicated gardener has scattered slug pellets in blissful ignorance, concerned only to protect plants against slime-trailing pests. However, a vocal chorus of "hazardous to wildlife" is causing the slug pellet to come under intense scrutiny.

It appears that the pellet's active ingredients - metaldehyde and methiocarb - are not broken down inside the slug or snail but remain active and harmful, not just to domestic pets but also to wildlife such as mice, hedgehogs and birds. The slug pellet is being accused of causing decline in Britain's song thrush populations, and may also have an impact on mammals and birds of prey further up the food chain.

At present there is a so-called wildlife-friendly slug pellet available, based on aluminium sulphate. However, it is easily washed away by rain. Not environmentally sound, and a big minus considering that slugs cause most devastation in wet conditions at night. Nevertheless, scientists are changing their tactics away from chemical pest control, and have come up with some intriguing solutions.

Allowing certain weeds to grow could protect agricultural crops and well- tended gardens alike from slug damage. Research at Kingston University has shown that slugs eat cultivated plants because there is generally nothing else on the menu; if the pests are offered a diversion in the form of a more appetising meal, they do less harm.

It was found in trials with 12 different weed species that slugs showed a preference for dandelions, with groundsel the most unappetising. Tests using wheat seedlings found damage was almost halved when dandelions were present, compared to wheat only.

Some plants, though, produce their own defence mechanisms against slugs. One research team found that many species of the carrot family triggered nervous activity in slugs, and that the poisonous weed hemlock contains a chemical that curtails their desire to eat. Tests are now being carried out on a synthetic form of that chemical extract, applied as a spray on various crops.

In the meantime, rather than showering the vegetable patch ad lib, try to catch a few slugs to test if enough are present to justify using pellets. The University of Newcastle, in conjunction with the pharmaceutical giant Rhone Poulene, has carried out experiments to find the best slug trap.

They tried ceramic tiles, plastic saucers, carpet, black plastic sheet, hardboard, dustbin lids, bricks, egg trays and linoleum. Easily obtained baits were used, such as wheat, potatoes, bran, layers' mash, cabbage, beer, and cat food.

The winning combination was a hardboard square baited with the hen food, layers' mash. This madean ideal way to determine whether enough pests were present to justify pellets being applied.

Perhaps the most revolutionary technique is to water the garden with a solution containing a tiny parasite. Discovered by Long Ashton Research Station, the nematode parasite preys exclusively on molluscs and poses no threat to other wildlife. It is killed at temperatures above 25C, therefore will not survive if accidentally eaten by a warm-blooded predator. One application lasts a season; the parasite dies out during cold weather.

For gardens, high-value horticultural crops, and organic farmers forbidden by Soil Association ethics to use chemical methods of control, this is an effective technique. However, it is too costly for general agricultural use.

Lastly, a tried and tested method of slug control that costs nothing: Place one boot, very heavily, straight down on to the pest and twist hard. Leave for the count of 10 seconds and remove.

Discover more property articles at Homes and Property
Arts and Entertainment
Reimagined: Gwyneth Paltrow and Toni Collette in the film adaptation of Jane Austen's Emma
Arts and Entertainment
Jesuthasan Antonythasan as Dheepan
Cannes 2015Dheepan, film review
Richard Blair is concerned the trenches are falling into disrepair
newsGeorge Orwell's son wants to save war site that inspired book
Arts and Entertainment
The pair in their heyday in 1967
Property search
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Guru Careers: Software Developer / C# Developer

£40-50K: Guru Careers: We are seeking an experienced Software / C# Developer w...

Guru Careers: Software Developer

£35 - 40k + Benefits: Guru Careers: We are seeking a Software Developer (JavaS...

SThree: Trainee Recruitment Consultant / Resourcer

£18000 - £23000 per annum + Commission: SThree: As a Trainee Recruitment Consu...

Ashdown Group: UI Developer - (UI, HTML, CSS, JavaScript, AngularJS)

£25000 - £40000 per annum: Ashdown Group: UI Developer - (UI, JavaScript, HTML...

Day In a Page

Abuse - and the hell that came afterwards

Abuse - and the hell that follows

James Rhodes on the extraordinary legal battle to publish his memoir
Why we need a 'tranquility map' of England, according to campaigners

It's oh so quiet!

The case for a 'tranquility map' of England
'Timeless fashion': It may be a paradox, but the industry loves it

'Timeless fashion'

It may be a paradox, but the industry loves it
If the West needs a bridge to the 'moderates' inside Isis, maybe we could have done with Osama bin Laden staying alive after all

Could have done with Osama bin Laden staying alive?

Robert Fisk on the Fountainheads of World Evil in 2011 - and 2015
New exhibition celebrates the evolution of swimwear

Evolution of swimwear

From bathing dresses in the twenties to modern bikinis
Sun, sex and an anthropological study: One British academic's summer of hell in Magaluf

Sun, sex and an anthropological study

One academic’s summer of hell in Magaluf
From Shakespeare to Rising Damp... to Vicious

Frances de la Tour's 50-year triumph

'Rising Damp' brought De la Tour such recognition that she could be forgiven if she'd never been able to move on. But at 70, she continues to flourish - and to beguile
'That Whitsun, I was late getting away...'

Ian McMillan on the Whitsun Weddings

This weekend is Whitsun, and while the festival may no longer resonate, Larkin's best-loved poem, lives on - along with the train journey at the heart of it
Kathryn Williams explores the works and influences of Sylvia Plath in a new light

Songs from the bell jar

Kathryn Williams explores the works and influences of Sylvia Plath
How one man's day in high heels showed him that Cannes must change its 'no flats' policy

One man's day in high heels

...showed him that Cannes must change its 'flats' policy
Is a quiet crusade to reform executive pay bearing fruit?

Is a quiet crusade to reform executive pay bearing fruit?

Dominic Rossi of Fidelity says his pressure on business to control rewards is working. But why aren’t other fund managers helping?
The King David Hotel gives precious work to Palestinians - unless peace talks are on

King David Hotel: Palestinians not included

The King David is special to Jerusalem. Nick Kochan checked in and discovered it has some special arrangements, too
More people moving from Australia to New Zealand than in the other direction for first time in 24 years

End of the Aussie brain drain

More people moving from Australia to New Zealand than in the other direction for first time in 24 years
Meditation is touted as a cure for mental instability but can it actually be bad for you?

Can meditation be bad for you?

Researching a mass murder, Dr Miguel Farias discovered that, far from bringing inner peace, meditation can leave devotees in pieces
Eurovision 2015: Australians will be cheering on their first-ever entrant this Saturday

Australia's first-ever Eurovision entrant

Australia, a nation of kitsch-worshippers, has always loved the Eurovision Song Contest. Maggie Alderson says it'll fit in fine