Fir diseases and their treatment

Spruce is a hardy tree

The fir tree is a conifer widely used as a houseplant, but the truth is that it cannot live indoors: drafts from air conditioning or heating, lack of light and the errors that are generally committed for your crop, such as watering. more frequently than it needs or fertilizing it when it is resting, makes its life very short. But be careful: when he is in the garden, his health can also be weakened.

And it is that pathogenic microorganisms, such as phytophthora for example, can cause many problems. For it, it is important to know the diseases of the fir tree and thus try to recover it.

Fir is a type of evergreen conifer found in temperate regions of the world. There are some, like the Korean fir (korean abies) which is so hardy that it is grown where the climate is generally mild in summer and very cold in winter. And it is that if there is something that all, or almost all, Christmas trees have in common, it is that They do not tolerate high heat very well, let alone drought.

But otherwise, We are talking about a plant that usually does not get sick. Of course, that doesn’t mean you can’t do it; not in vain, he does not cease to be a living being and, as such, his state of health may weaken. But fortunately, it is not the tree that has the most diseases. In any case, we want your tree to be healthy and precious for as long as possible, so let’s talk about the pathologies that can affect it:


Fir Needle Fused

Fused fir needle is a disease

Image – Andrej Kunca

This curious name is that of the disease caused by the fungus Rabdoclina pseudotsugaewhich mainly affects trees of the genus Pseudotsuga and Tsuga, but also firs.

In these plants, what it does is cause leaf deathdrying the branches from the tip backwards.


If you detect symptoms in your plant, You need to cut off the affected part and seal the wound with healing paste. Additionally, you should treat it with a systemic fungicide like this.

Browning of conifers

Virtually all conifers can be affected by oomycete Phytopthora cinnamomi. Pines, cypresses, firs, yews… The causes are very varied.: soil too heavy, excess water, plants planted too close together, lack of nutrients, among others.

Related article:

Why do conifers turn brown?

When it occurs, the leaves are seen to dry up quickly due to root rot.


Both to prevent and to try to cure, fungicides should be applied against phytophthora like Aliette (on sale here) in spring and summer.


The tree can have cancer

Image – Joseph O’Brien

Americans call it spruce canker. It is caused by fungus Leucostone kunzei what it does is destroy the plant from within, causing early leaf death and trunk disfigurement. In addition, when a branch falls, it leaves a stain of resin.

It affects both firs (i.e. trees of the genus Abies), as well as Picea and other trees, such as peach trees. Now well, it is difficult for them to get sick if they receive proper care and pruning is avoided (or in the event that this is done, care is taken to use appropriate and clean tools).

Indeed, the most vulnerable specimens are those which suffer from water stress due to lack or excess of water, those which have a root system that is still underdeveloped or unhealed pruning wounds. Likewise, You should know that old trees have a higher risk of suffering from this disease.


Unfortunately, The most effective treatment is prevention.. Try to plant the fir tree in fertile, well-drained soil, where the climate is temperate, with mild temperatures in summer and low temperatures in winter. In addition, keep in mind that it is better not to prune it: the fungi take advantage of these wounds to gain access to the interior of the plants, and thus infect them.

In the event that it has to be done, it will be done at the end of winter with clean pruning tools and disinfected with water and dish soap, and a healing paste will be applied after each cut.

spruce heart rot

There are fungi that affect spruce

Image – Wikimedia/Jerzy Opioła

It is a pathogenic fungus whose scientific name is Phellinus hartigii which feeds on old trunks of firs, spruces and pines. When it becomes visible, it takes the form of a triangular hoof about 20 centimeters wide by 25 centimeters high.generally covered with lichens.

Symptoms may be confused with those of natural tree aging, such as gradual leaf drop, or slower growth. Now, if properly cared for, it will prevent the plant from dying prematurely.

As you can see, there are few diseases that fir can get. But, I insist, it is important to know the needs of the plant that we are going to buy, otherwise it will be very easy for it to get sick.

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