As professional tree surgeons and arborists we know a thing or two about this disastrous disease so we thought we’d share a little of that information with you, so you can help us in the battle to save the English elm.
The story of a killer
Discovered in 1910, this tree disease merrily ravaged its way through Europe’s elm population for almost 30 years before subsiding in the 1940s after killing up to one in four trees in some countries.
Then in the 1960s a more virulent strain of the disease hit Britain, and 30 years later over 80% of the UK elm population was gone. If you live in southern Britain that figure goes up to almost 100% of all mature elm trees as the English elm is more susceptible to the disease than those further north.
The guilty party close up
Dutch elm disease is a fungus that infects trees and is spread by elm bark beetles – large black/brown members of the weevil family that grow to around half a centimetre in length. These beetles feed off the younger twiglets at the tops of healthy elm trees. As they feed they spread the Dutch elm disease fungus. The tree reacts by closing down all its water carrying vessels where the infection starts. But the fungus spreads so rapidly this immune response does nothing to stop the disease. Eventually, the entire tree dries out as the immune response peaks, and unfortunately this creates the perfect breading and egg laying ground for those same elm bark beetles.
In late spring/early summer you may begin to notice some of these symptoms: