Hymenoscyphus fraxineus / Chalara fraxinea / ASH DIEBACK

Dutch Elm Disease for the 21st century. Like it or not, it’s going nowhere. Well, actually, it’s going everywhere, including the South Hams.

Left: Healthy Ash, Centre: Javier dismantling an infected Ash.

There is no cure or treatment for the disease and over time infected trees will weaken, causing branches to fall and trees to eventually collapse and die. Infection can lead to the death of young trees in just two to three years and of mature trees within 3 to 5 years. This presents a significant health and safety risk, especially alongside roads, public rights of way and woodland areas used by the public for recreation activities. (source: gov.uk)

Dieback showing in twigs at the top of the crown.

Symptoms of ash dieback include;

  • On leaves: Black blotches appear, often at the leaf base and midrib. Affected leaves wilt
  • On stems: Small lens-shaped lesions or necrotic spots appear on the bark of stems and branches and enlarge to form perennial cankers. The infection may girdle the stem and kill it in a single season. If the bark is peeled, the wood underneath has a brownish to grey discolouration. This discolouration extends beyond the bark necrosis
  • On the whole tree: Affected trees show extensive dieback of shoots, twigs and branches. Trees often have prolific epicormic shoots (shoots produced from previously dormant buds below the bark of the trunk or branches) (source: rhs.org.uk)
Signs of dieback on stems.