The largest impact of needle diseases in the recorded history of Pinus radiata and Pinus nigra plantations in the North of Spain, was from 2018 to 2019. The severity of the disease has led to a serious reconsideration of forest management in the area. The main pathogens involved in this historical outbreak were Lecanosticta acicola and Dothistroma septosporum. Three arboreta were established under the European project REINFFORCE in the Basque Country in recently harvested P. radiata plantations. The plants for the arboreta were produced in nurseries located in the Alps of Upper Provence (France). These arboreta were surrounded by plantations seriously damaged by L. acicola and D. septosporum. The Pinus species which were sampled in the arboreta included P. brutia (4 provenances), P. elliottii (2 provenances), P. nigra (8 or 9 provenances), P. pinaster (7 provenances), P. pinea (6 provenances), P. ponderosa (3 provenances), P. sylvestris (8 provenances) and P. taeda (3 provenances). Lecanosticta acicola is reported for the first time infecting Pinus brutia (Provenance: Alexandropolis, Greece and var. eldarica, Crimea), a new host species for this pathogen. Pinus elliottii (Provenance: Georgia, USA) and P. ponderosa (Provenance: Central California, USA) are new host reports of L. acicola for Spain. Dothistroma septosporum was found for the first time on P. brutia (Provenance: Marmaris, Turkey) and P. ponderosa (Provenance: Oregon, USA) in Spain and was also detected infecting P. nigra (Provenance: Slogne Vayrières, France).