“False White Stemcup” what a cute name for such an aggressive pest. Since 2007, Hymenoscyphus pseudoalbidus, a dangerous fungus from East Asia, has also been wreaking havoc in Germany and is destroying more and more ash trees. Do you suspect that your ash tree could also be infected? Read more about the symptoms of the disease here.
What are the symptoms of ash tree disease?
Ash disease is caused by the aggressive fungus Hymenoscyphus pseudoalbidus, which causes wilted leaves, discolored bark and altered crown growth habit. Young ash trees usually die within a year, while old ash trees weaken over time.
Symptoms
- withered leaves
- discolored bark
- changed growth habit of the crown
Withered leaves
First, brown necrosis appears on the leaves. From July onwards these begin to wilt before the ash tree rejects them completely. This process is actually very atypical for the deciduous tree. You can also observe the formation of leaf spots.
Discolored bark
Are the side shoots of your ash tree turning yellow or pink? This is also a clear sign. Over time, the shoots will die off completely. A cross section of the tree clearly shows that unusual grains that do not correspond to the pattern of the annual rings are formed.
Changed growth habit of the crown
The crown becomes thinner and thinner as the shoots die. The ash tree reacts to this with strong branching and tuft-like growth forms of the branches.
Infestation of young ash trees
Young ash trees suffer particularly from the fungus' attack, as their narrow trunks have little resistance to the death of ash shoots. Fresh shoots are attacked first. The tree usually dies completely within a year.
Infestation of old ash trees
The disease progresses somewhat more slowly on old trees. They don't die immediately, but they get weaker over the years. The crown thins out significantly and the ash tree becomes very vulnerable to the weather.
Is there an antidote?
Researchers are currently searching in vain for an effective treatment. However, there is hope in the observation that isolated ash trees that stand next to severely diseased trees only show minor symptoms. They are probably genetically resistant to the pest.
