The Obama flatworm (Obama nungara), which grows 7cm long, is a predator of earthworms and land snails, thereby endangering soil fertility and wildlife. It was first found in Europe on Guernsey in 2008, but has spread through France and into Spain and has now been discovered at a handful of locations in the UK.
In the latest incident a 4.5 cm worm crawled out of a pot plant that had been bought in a garden centre in Oxfordshire. The plant, a Heuchera, had been imported from the Netherlands. The worm was sent to wildlife artist Richard Lewington who, with the national flatworm recorder Hugh Jones, was able to identify it as Obama nungara.
HTA horticulture head Raoul Curtis-Machin said: "This discovery is a concern to the industry. Although unexpected, it's not a great surprise because there have been incidences of flatworms before. It will feed into discussions with government about how we can all strengthen biosecurity.
"We want to safeguard the rich diversity and broader benefits of exotic plants and gardens, whilst minimising the risk to our native species from imported stock.
"It illustrates the importance of traceability in the supply chain, which is something we are working on with a prototype plant health management system for nurseries."
This is not the first invasive flatworm to arrive in the UK New Zealand and Australian flatworms are already established and have reduced some earthworm populaions by 20 per cent.
It may not be the last either, there are 18 invasive flatworms already in Europe and "the uncontrolled trade in pot plants is rapidly spreading them", says Buglife. Buglife adds that some have even worse reputations for causing environmental harm: the New Guinea flatworm has arrived in France and is one of the "100 worst invasive alien species" in the world.
Buglife chief executive Matt Shardlow said: "The importation of pot plants into the UK is bringing with it an avalanche of harmful and unwanted species. At Buglife we are regularly alerted to exotic grasshoppers, wasps, beetles, spiders and moths arriving at nurseries and garden centres, many of these animals have the potential to damage agriculture, destroy wildlife or distress gardeners. Our biosecurity is feeble, it is time for the Government to take control of this problem before it gets completely out of hand and we are unable to recognise the wildlife in our own gardens."
The worm’s genus name, Obama, comes from the Brazilian Tupi language words for leaf (oba) and animal (ma).
Damage from invasive species is calculated to cost the UK £1.8 billion per annum.
Buglife points out that more than £1 billion pounds of live plants are imported into the UK every year, and "for the vast majority there are no biosecurity measures to exclude or check for eggs or hibernating animals in the soil".
Other invasive species that Buglife says are likely to have arrived in the pot plant trade include:-
· Rosemary leaf-beetle
· Australian flatworm
· New Zealand flatworm
· Spanish slug
· Lily beetle
· Oak processionary moth
· Asian hornet
· Harlequin ladybird
· Three-lined balkan slug
· Yellow and green cellar slugs
Buglife added: "In the wake of the importation of Ash die-back the Government undertook a review of phyto-sanitary health in relation to the importation of live plants, however the review did not consider the wider biosecurity issue associated with importing hundreds of thousands of tonnes of soil into the UK every year. Plant health is an easier problem to address than biosecurity.
"Consumers should buy British to avoid aiding and abetting biosecurity breaches. Peat use and neonicotinoid contamination are other environmental issues associated with the pot plant industry."
The worm is still alive and being kept.