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The elms back to die, but not all!

Observing our campaigns, we observe the great dying of elm trees which this year is featuring the landscape. The elm (Ulmus minor), is one of the species most susceptible to a disease called graphiosis elm, this disease is caused by a fungal pathogen of Asian origin, Ophiostoma ulmi sl, which at the beginning of the century last year, ravaged European elm populations quickly and then those of North America.

A little history. After the first epidemic wave, beginning in the 70s, the disease has had a strong resurgence following the introduction of virulent strains from North America. This second wave of epidemic led to the disappearance of the species of elm European and serious damage to the economy, the environment and especially to the urban landscape. In fact, the elm trees were an important element in urban design of the main Italian and European cities and they were still considered an important resource in the agricultural economy Italian, not easily replaceable with other plant species.

Symptoms and damage. The pathogen acts coming into contact with healthy plants in the upper portion of the canopy through the nutritional activity of some bark beetles insects that fulfill their biological cycle from sick to healthy elms, thus spreading the disease. From the time of inoculation, soon we note the appearance of yellow leaves and withered over the entire upper part of the crown. The development of symptoms in the spring time is very fast and intense, more than in summer. When infection occurs through contact between radical diseased plants and healthy, the symptoms are more intense and withering of the plant dies quickly. The favorable climatic conditions for the flicker of the young adults of bark beetles and the presence of a sufficient number of plants already infected with dimensions suitable for oviposition are the characteristics that have allowed this year the occurrence of a new epidemic wave.

The research led to resistant varieties. Thanks to the observations and studies on the disease and research programs on genetic improvement made by various research institutes, such as in Italy, the Institute for Plant Protection (IPP) of CNR, it was possible select plants resistant to DED. 'Saint Zenobius', 'Pliny', 'Arno', 'Flourishing' and 'Morpheus' are the five clones of elm patented IPP CNR, which combine the good characteristics of the vegetative European elms with remarkable resistance to disease the East.

New horizons: the return of the Elm. Thanks to the use of these clones, both from the government that the private sector, the elm you will be able to regain possession of their spaces, at least in the contexts ornamental. Moreover, these clones patented are also characterized by a rather rapid growth that suggests the use for the production of biomass and also valuable timber.

As for the existing assets we'll have to see a gradual decline and, once again, these majestic plants are transformed into bushes, the use of plants that are resistant to the pathogen, in a more systematic and widespread, it may be a way to counter the spread of the disease and to be able rifruire of this beautiful plant, which since prehistoric times has been an asset to the man and to the environment.

The research has led to some clones resistant to graphiosis. So you recover a heritage important