REINFFORCE Arboretums: Sentinel devices against pathogens at the European level. – Institut Européen de la Forêt Cultivée
IEFC Newsletter 2021 Mars REINFFORCE Arboretums: Sentinel devices against pathogens at the European level.

REINFFORCE Arboretums: Sentinel devices against pathogens at the European level.

REINFFORCE Arboretums: Sentinel devices against pathogens at the European level.

Between 2011 and 2013, thanks to the REINFFORCE project of the Interreg Atlantic Area programme, a collection of 38 arboretums with different origins from 32 different forest species was established along the European Atlantic coast (from Scotland  to Portugal). The aim was to observe their growth, phenology and condition that different diseases and pests might have on them in different European climates in order to understand their possible future behaviour. The idea was, in the context of climate change, to change the time variable to the space variable, being aware that the future climate in some European  regions  will be similar to the current climate in other regions of the continent. In the Basque Country, 5 arboretums were established: one in Albina (Araba), one in  Irisasi  (Gipuzkoa) and three in  Unbemendi  (Bizkaia). Between 2018 and 2019 there was a large outbreak of diseases caused by Lecanosticta acicola  (Brown spot  needle   blight) and  Dothistroma septosporum and D. pini  (red band  needle  blight) in forests of radiata pine (Pinusradiata) and laricio pine (Pinus nigra)  in the Basque Country.   It was  recently observed  that some of the pines planted in the REINFFORCE arboretums in this region had symptoms of defoliation and discoloration compatible with these diseases. For this reason,  between 2019 and 2020 the sensitivity to these diseases of different origins of  some  of the  pine species  planted in these arboretums was studied. 

In the three arboretums, between 3 and  11 origins of the same eight species of pine trees had been established,  a total of 42 origins. These were 4 origins of  P. brutia  Ten. (Alexandropolis,  Greece; Marmaris,  Turkey; Taurus,  Turkey; var.  Crimea), 2 origins of   P.elliottii Engelm. (Georgia, USA; Louisiana, USA),  9 of  P. nigra Arnold (Cazorla Alcaraz,   Spain; Les Barnes  Sivens, France; Sistema Iberico Meridional,  Spain; Slogne  Vayriéres, France; subsp.  laricio  var. corsican, Haute Serre  seed  tree  orchard, France; subsp.  salzmannii, Soria,  Spain; subsp.  laricio  var. Calabrica, Les Barnes-Sivens, France; subsp.  salzmannii  – ES07b – Sistema Iberico Meridional, Sud de Cuenca,  Spain),  7 of  P. pinaster  Ait. (Cordal de Loba, Spain; Leiria, Portugal;  Mimizan, Landes, France; Picard, Lande  Corse, France; Serrania  de Cuenca,  Spain; Sierra de Gredos,  Spain; Tamjout,  Morocco),  6 of  P. pinea  L. (Italy; Région  méditerranéenne, France; Tietar and    Alberche Valleys,  Spain; Vendas Novas, Portugal; ES A – Biar –  Spain; Malaga  –  Spain),  3 of  P. ponderosa Douglas ex C. Lawson  (Oregon,USA; Southern  Rockies, USA; Central California, USA),  8 of P. sylvestris L. (ES10 – Sierra de Guadarrama, Spain; 5,  Severozapadna, Slovakia; Turkey;  Pinhal  da  Pedra  Bela, Portugal; Scotland, UK (204);  Taborz,  Polland Haute Serre, French  Seeds  Orchard; ES12, Montes Universales,  Spain; Haguenau  Vayriere, France) and  3 of  P. taeda  L. (Hardiness  Zone  Georgia  Seed Orchard, USA; Southern  California, USA; Virginia, USA).

The trees were visually inspected in the spring of 2019-2020 for symptoms. Samples of acicles were taken and isolations were performed,  where possible. Molecular  analyses of both trees with symptoms and trees that did not present them were performed and PCR  tests (PCR, RTPCR and sequencing) were performed to determine the presence of L. acicolaD. septospurum  and  D. pini. A total of 113 pines showed symptoms of the disease; 42 in Albina, 18 in  Irisasi  and 53 in  Unbemendi.

P. ponderosa  was by far the species with the most positive detections (68%) followed by  P. brutia  (38%),  P. nigra  (12%) P.  elliottii  (7.7%). P. pinaster,  P. pinea,  P. sylvestris  and  P. taeda had no symptoms in the three arboreta. Of  the 113 trees sampled, 23 tested positive for  L. acicola  or  D. septosporum.

Unlike previous results no more than one pathogenic species was found infecting a tree. Eugenia Iturritxa,  Nebai Mesanza and Monica Hernandez  report detection of Lecanosticta acicolaen  Pinus brutia  (Alexandropolis, Greece and var. Eldarica, Crimea),  being a new host species of this pathogen on a global scale. For the first time in  Spain, L. acicola  was found  in P. elliottii  (Georgia, USA) and P.  ponderosa  (Central California, USA). Dothistroma septosporum  was found in P. brutia  (Marmaris, Turkey),  P. ponderosa  (Oregon, USA) P.  nigra  (Slogne Vayriéres, France).

REINFFORCE arboreta are valuable tools as sentinel devices for detecting species sensitivity to new pathogens as well as existing pathogens. In the light of these results, it is possible to start choosing the origins  of species of interest in which diseases is unlikely to  affect  their development in different European regions.

by: Dr. Ander Arias Gonzales (NEIKER)