Dutch elm disease which has so far attacked more than three million trees in Britain is spreading, according to Forestry Commission officials.
Tests on a tree in Wakefield have confirmed the blight is now present in Yorkshire in the north of England.
Previously it had been confined to the south of the country.
Three hundred thousand trees in Wiltshire and more than three-quarters of the elms in Gloucestershire have been affected.
In West Sussex the situation is even more acute with more than 90% of the county’s elms already felled or infested.
The outbreak has been traced to Canadian timber which arrived in Britain seven years ago.
It causes branches and leaves to shrivel suddenly and can kill a century-old elm within a few months.
The fungus is being spread by the elm bark beetle which flourishes in hot dry weather.
The recent heat wave has been an aggravating factor in speeding up the infection rate according to Forestry Commission spokesman David Rooke.
“In this weather the beetles which carry the virus fly more and breed more.
“The drought has not helped trees that were sickly which might have recovered in a summer with normal rainfall,” Mr Rooke said.
Nearly two million elms are expected to die this year.
The Forestry Commission has said that disposing of infected trees could cost up to £50m over the next five years.
Courtesy BBC News
In context
Scientists have never established where Dutch elm disease originated but it was formally identified some 80 years ago in Holland.
Before the British outbreak it had long been a scourge in both north America and across much of Europe.
In 1968 imported Canadian timber carrying a new virulent strain of the Dutch elm disease sparked the British epidemic.
The most effective way of treating the disease was a chemical treatment which had around an 80% success rate.
But the government considered the procedure too expensive except for trees which had great environmental importance.
More than a third of southern England’s 23 million elms perished in the outbreak.
No Comments