Sick cypress

Question: what to do with a sick cypress?

I own a row of leylands of different varieties along one of the fences (hilly area of ​​Sicily) about 6 meters high. Recently one of these started from the bottom to dry the twigs now and totally dry up to the top. I wanted to know if I have to have it removed urgently and if I have to treat the other leylands with any product, some of them have already for some years dried down branches and the bark completely crumpled and when you remove it with your finger underneath, a red color appears intense is there hope to cure them or should they also be eliminated?

Sick cypress: Answer: cypress cancer

Dear Giuseppe,
cupressocyparis leilandii is a cupressacea very sensitive to cypress cancer; this disease is caused by a fungus, which spreads in the cracking of the bark, in the cracks due to the weather, or even in the pruning cuts; unfortunately it is a very subtle disease, because it spreads by air, and often remains at rest, without manifesting itself, until the plant has reached a certain size; in particular, this cancer begins to appear in cypress trees that have reached at least 3-4 meters in height. The only thing one can do (indeed, one must do), when a cypress manifests this pathology, consists in eradicating it and destroying it; then he eradicates the sick cypress, takes all the wood away from the garden, burns everything, and collects the ash, which will be thrown into the solid urban waste (in the undifferentiated). To prevent the disease from manifesting on the cypresses next to it, provide with copper-based treatments, or with Bordeaux mixture, to be carried out in late winter and autumn. In addition to this, we usually try to avoid this type of plants for hedges, because they tend to get cancer irreparably. In general, then, the cancer tends to penetrate through the bark, at the points where it breaks for accidental reasons, but also in the cuts due to pruning: if you make any type of pruning on your hedge, it is essential that you go to close each cut with of mastic for pruning, which in addition to promoting the healing of wood, generally contains a broad-spectrum fungicide, which kills any fungi present on the cut.