BRITAIN'S earthworms, which are being devoured by two foreign species of flatworm, are in further danger after a third species was found recently in an Edinburgh garden.
A flatworm expert yesterday advised all gardeners to lay traps for the creamy white invaders and kill any they find. The previous killers had arrived from New Zealand and Australia but the new alien was unknown to experts.
The new worms were passed to Dr Brian Gerard, of the Scottish Agricultural College, who nurtured them in his garage until they died.
Now they have been passed to Dr Hugh Jones, a zoologist at Manchester University.
He said: "As yet we don't know what species it is. I have been looking at it now for a week and it is none of the obvious species from either New Zealand or Australia."
No action was taken over the previous two killer species until it was too late and scientists fear that, when it gets colder and worms emerge from the soil, they may find that the new species has taken hold.
Earthworms are essential for draining soil and for breaking down organic matter to make nutrients available to plants. They are also a major food supply for wildlife.
The first flatworm invader arrived from New Zealand in the 1960s. It has damaged more than 150 square miles of soil in Northern Ireland and infected more than a dozen Scottish farms, reducing earthworm numbers to a level where they can no longer be detected.
The second flatworm arrived from Australia in the 1980s and is more common in south-west England.
Dr Brian Boag, a soil ecologist at the Scottish Crop Research Institute in Dundee, said that an invasion could have begun from a single flatworm egg capsule, containing up to 10 eggs, which could have been clinging to soil round the bottom of an imported plant.
Gardeners could lay traps for the new invader by leaving a stone or piece of wood in the garden during the autumn, when flatworms are more likely to emerge from the ground, and checking underneath it every day.
Any flatworms that fitted the description should be killed, said Dr Boag.
