Native and imported diseases
About 200 years ago, the Douglas fir immigrated from North America to Europe, where it feels very comfortable and is now quite widespread. But unfortunately it is also prone to some native tree diseases.
also read
- Douglas fir fact sheet - numbers, facts and special features
- What care do daffodils require in the home?
- Planting Douglas fir - a good start to a long life
In the meantime, pathogens have also been introduced from their homeland, and more may be added.
Young trees are more susceptible to disease
Especially young Douglas firs are susceptible to disease because they are not yet sufficiently strengthened. It is primarily fungi that bother the tree. First of all, the following diseases are to be mentioned:
- Rusty Douglas fir (Rhabdocline pseudotsugae)
- Sooty Douglas fir (Phaeocryptopus gäumannii)
- Root rot
Tips
At a young age, Douglas firs can be treated preventively with plant strengtheners.
Rusty Douglas fir chute
In damp locations and if the vegetation is too dense, the two Douglas fir piles caused by hose fungi can spread. The rusty Douglas fir chute manifests itself with the following symptoms:
- Needles turn yellow-brown
- needle loss soon follows
- there is a strong loss of growth
- if the infestation is severe, pests or other types of mushrooms
This fungal disease rarely leads to the death of the tree, as the upper parts of the tree are usually spared. However, if bark beetles or the Hallimaschpliz spread, the life of the tree is seriously threatened.
Tips
The so-called coastal Douglas fir is less susceptible and is therefore often planted with pleasure.
Sooty Douglas fir chute
This hose fungus spreads faster, which is why the tree often dies within a year.
- needles turn yellow in spring
- starting from the middle of the tree
- later they fall off completely
Spraying with fungicides alleviates the visible symptoms, but does not eliminate the cause of the disease, which is why they ultimately remain ineffective.
Different root rot fungi
The Douglas fir is one of the most sensitive conifers when it comes to root rot. Injuries to the bark and roots make it easier for a fungal pathogen to penetrate the inside of the tree, where it remains undetected for a long time and the tissue gradually decomposes. If it is discovered because it forms visible fruiting bodies on the trunk, any help will come too late.
That is why it is important to avoid any injury. Even when planting, care must be taken that the roots are not damaged. This also applies to all excavations in the root area.
