On this day in history : 5th August 1975 – The Forestry Commission officially announces the spread of Dutch elm disease in Britain…. To date over 60 million British elms have been lost….

Dutch elm is one of the most serious tree diseases in the world and infects all of Britain’s major elm species…. The fungus is spread by the bark beetle in the genus Scolytus and invades the water conducting system of the tree…. The symptoms first appear early summer, clusters of leaves wilt and turn yellow….they then turn brown and fall…. Affected shoots begin to die back….dark streaks appear in the outer wood under the bark and twigs may dip down to form a ‘shepherd’s crook’….

The crown of a diseased elm…. Note the dying back of branches in multiple places. Image credit : Ptelea – Public domain

It is believed the disease originally came from Asia – and was accidentally introduced to the USA and Europe…. It was first noticed on continental Europe in 1910 and first identified in England, on an English elm in Hertfordshire by T.R.Peace, in 1927…. However, this particular outbreak was relatively mild, often just killing a few branches and had largely died out by the 1940s…. The name Dutch elm disease refers to its identification by Dutch scientists in 1921….

However, in 1967 a far more virulent strain emerged…. It apparently arrived via the east coast ports on shipments of elm from Canada bound for the boat industry…. This was confirmed in 1973 on another consignment examined at Southampton Docks…. By the mid 1970s millions of trees had been wiped out, within ten years it had reached Scotland…. By 1990 very few mature elms were left in Britain and much of Europe; the largest concentration of mature elms in the UK are now in the Brighton and Hove area of Sussex….

You may sometimes see saplings growing in hedgerows…. The roots of the elm are not killed and sends up suckers – but rarely do they reach above 5m high….before succumbing to a new attack of the fungus….

Image credit : Dougie Nisbet via Flickr

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