Article An Overview of Phytophthora Species Inhabiting Declining Quercus suber Stands in Sardinia (Italy) Salvatore Seddaiu 1, Andrea Brandano 2, Pino Angelo Ruiu 3, Clizia Sechi 1 and Bruno Scanu 2,4,* 1 Settore Difesa Delle Piante Forestali, Agris Sardegna, Via Limbara 9, 07029 Tempio Pausania (SS), Italy;
[email protected] (S.S.);
[email protected] (C.S.) 2 Dipartimento di Agraria, Sezione di Patologia Vegetale ed Entomologia, Università degli Studi di Sassari, Viale Italia 39, 07100 Sassari, Italy;
[email protected] 3 Settore Sughericoltura e Selvicoltura, Agris Sardegna, Via Limbara 9, 07029 Tempio Pausania (SS), Italy;
[email protected] 4 Nucleo Ricerca Desertificazione, Università degli Studi di Sassari, Viale Italia 39, 07100 Sassari, Italy * Correspondence:
[email protected] Received: 13 August 2020; Accepted: 4 September 2020; Published: 8 September 2020 Abstract: Cork oak forests are of immense importance in terms of economic, cultural, and ecological value in the Mediterranean regions. Since the beginning of the 20th century, these forests ecosystems have been threatened by several factors, including human intervention, climate change, wildfires, pathogens, and pests. Several studies have demonstrated the primary role of the oomycete Phytophthora cinnamomi Ronds in the widespread decline of cork oaks in Portugal, Spain, southern France, and Italy, although other congeneric species have also been occasionally associated. Between 2015 and 2019, independent surveys were undertaken to determine the diversity of Phytophthora species in declining cork oak stands in Sardinia (Italy). Rhizosphere soil samples were collected from 39 declining cork oak stands and baited in the laboratory with oak leaflets. In addition, the occurrence of Phytophthora was assayed using an in-situ baiting technique in rivers and streams located throughout ten of the surveyed oak stands.