This article is from the source 'guardian' and was first published or seen on . It last changed over 40 days ago and won't be checked again for changes.

You can find the current article at its original source at http://www.theguardian.com/environment/2016/apr/26/oriental-chestnut-gall-wasp-threat-uk-sweet-chestnut-trees-pest

The article has changed 2 times. There is an RSS feed of changes available.

Version 0 Version 1
Asian wasp listed as threat to UK's sweet chestnut trees Asian wasp listed as threat to UK's sweet chestnut trees
(about 20 hours later)
An Asian wasp that threatens the UK’s sweet chestnuts has been designated a high-priority tree pest for the first time.An Asian wasp that threatens the UK’s sweet chestnuts has been designated a high-priority tree pest for the first time.
The oriental chestnut gall wasp (Dryocosmus kuriphilus) was first found in the UK last year, in Farningham woods near Sevenoaks in Kent, and a street in St Albans in Hertfordshire.The oriental chestnut gall wasp (Dryocosmus kuriphilus) was first found in the UK last year, in Farningham woods near Sevenoaks in Kent, and a street in St Albans in Hertfordshire.
On Tuesday the Forestry Commission said it was elevating the wasp to its list of high-priority tree pests because of the 2015 outbreaks.On Tuesday the Forestry Commission said it was elevating the wasp to its list of high-priority tree pests because of the 2015 outbreaks.
There are 268 pests on the UK Plant Health Risk register but just 12 are ranked as high priority because of their impact and likelihood, including the fungus that causes ash dieback, sudden oak death disease and the emerald ash borer.There are 268 pests on the UK Plant Health Risk register but just 12 are ranked as high priority because of their impact and likelihood, including the fungus that causes ash dieback, sudden oak death disease and the emerald ash borer.
While the wasp poses no risk to humans and pets, its larvae cause abnormal growths — the eponymous galls — on sweet chestnut trees. These can weaken the tree and leave it more vulnerable to other pests and diseases.While the wasp poses no risk to humans and pets, its larvae cause abnormal growths — the eponymous galls — on sweet chestnut trees. These can weaken the tree and leave it more vulnerable to other pests and diseases.
The wasp itself emerges in June and July, and has orange legs and a black body, but is easily missed at only 2.5-3mm long.The wasp itself emerges in June and July, and has orange legs and a black body, but is easily missed at only 2.5-3mm long.
The galls protect the species from insecticides, so eradication efforts have so far concentrated on felling. Felling trees at the “isolated finding” in St Albans, where it was spotted by the daughter of a tree health volunteer, appears to have wiped the wasp out there.The galls protect the species from insecticides, so eradication efforts have so far concentrated on felling. Felling trees at the “isolated finding” in St Albans, where it was spotted by the daughter of a tree health volunteer, appears to have wiped the wasp out there.
However, at Farningham woods in Kent, where four hectares of a 79-hectare wood have been felled, further surveys are planned this year.However, at Farningham woods in Kent, where four hectares of a 79-hectare wood have been felled, further surveys are planned this year.
The commission said other eradication measures could be considered. “In the long term there could be the possibility of using a parasitoid organism to achieve a measure of ‘biological control’, but this would need careful research beforehand to ensure that the control organism itself would not cause environmental damage.”The commission said other eradication measures could be considered. “In the long term there could be the possibility of using a parasitoid organism to achieve a measure of ‘biological control’, but this would need careful research beforehand to ensure that the control organism itself would not cause environmental damage.”
A commission spokesman added: “Oriental chestnut gall wasps were found at two sites in England in 2015 and swift and extensive action was taken immediately to help eradicate the species. We will continue to survey for the pest this summer in high-risk areas across south east England.”
Nick Atkinson, senior conservation adviser at the Woodland Trust, said: “The arrival of another pest in the UK reminds us how pathways are still open for these threats, which is also why it’s so important for anyone who loves trees and woods to be vigilant and help identify possible outbreaks at an early stage.Nick Atkinson, senior conservation adviser at the Woodland Trust, said: “The arrival of another pest in the UK reminds us how pathways are still open for these threats, which is also why it’s so important for anyone who loves trees and woods to be vigilant and help identify possible outbreaks at an early stage.
“We hope this may be an isolated case but we need to do all we can, particularly at our borders, to prevent new pests or diseases establishing.”“We hope this may be an isolated case but we need to do all we can, particularly at our borders, to prevent new pests or diseases establishing.”
Officials are investigating how the wasp, which is already found throughout much of mainland Europe, arrived in the UK. A 2010 European Food Safety Agency assessment of the insect found that it was highly likely to spread throughout Europe but its impact could be mitigated through management.Officials are investigating how the wasp, which is already found throughout much of mainland Europe, arrived in the UK. A 2010 European Food Safety Agency assessment of the insect found that it was highly likely to spread throughout Europe but its impact could be mitigated through management.
The UK’s sweet chestnut trees have already