Question: What parasite afflicts my viburnums?
First of all, congratulations on your beautiful magazine that I receive every month! I have a problem to submit to you and for which I have not found answers on the internet. I have 9 viburnum plants which are trees .... one is dying ... I looked for parasites and saw that the bark of the trunks is eaten and therefore has all the white part exposed (which is also quite sticky). The other plants are also barked ... what can it be ?? I look forward to an answer to be able to promptly intervene! Thank you very much also on behalf of my plants (another almost three meters).
Parasite under the viburnum bark: Answer: dangerous parasites
I believe that your viburnums are suffering from some kind of fungal disease, which is developing under the bark, starting from the roots, damaging the wood of the plants; in general, these are fungi that originate in the soil, when it is damp and asphyxiated for a long time, causing rot in the root system of your saplings. From the roots, the fungi develop rapidly, living undisturbed under the bark; if it is actually this type of parasite, there is not much to do for your plants, which will be uprooted and burned, to prevent the fungus from spreading throughout the garden, even on other plants.
To know for sure that it is a mushroom, you should carefully observe the whitish patina that you see under the bark, it should be silky to the touch, and it should have the smell of mushroom, like that of champignons.
In fact, not having the opportunity to see your plants live, before deciding that it is actually a fungus, it is advisable that you consult an expert gardener, in order to implement the most suitable care. It could also be another type of fungal disease, which must be eradicated with copper-based treatments; it could be a fungus that did not hit the roots, but only the wood, and therefore the removal of the damaged branches could completely solve the problem.
Unfortunately, since there are so many variables and not being able to see for yourself the problem that afflicts your viburnums, it is not easy to make a certain and definitive diagnosis. When we see plants in the garden that show symptoms completely different from those we have been able to observe in our garden, it is always advisable to contact a nurseryman or a gardener, or even an agricultural consortium if we have one close to home, in order to be sure how to act on the problem.
Unfortunately in a case like this it would be necessary to have at least one sample of the damaged wood, as not even a photograph can help us to understand with certainty what the problem is.
In fact, it could also be insects, although in this case you should see them, partially peeling the bark and lifting it.
The most probable hypothesis is unfortunately that it is root rot that is developing below the bark, rising from the roots to the apex of the stems; if the infestation has started recently, and is not very widespread, it is not necessarily said that the only method to eradicate it consists in killing the plants.