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Three new lactones and a new fatty acid ester, named sapinofuranones C and D, diplopyrone B, and diplobifuranylone C, respectively, were isolated from Diplodia corticola, together with sphaeropsidins A and C, diplopyrone, diplobifuranylones A and B, diplofuranone A, and the (S,S)-enantiomer of sapinofuranone B. Sapinofuranones C and D, diplopyrone B, and diplobifuranylone C were characterized as (5S)-5-((1,S-1,6-dihydroxyhexa-2,4-dienyl)-dihydrofuran-2-one, 4,5-dihydroxy-deca-6,8-dienoic acid methyl ester, (5S)-5-hydroxy-6-(penta-1,3-dienyl)-5,6-dihydro-pyran-2-one, and 5'-((1R)-1-hydroxyethyl)-2',5'-dihydro-2H-[2,2']bifuranyl-5-one by spectroscopic and chemical methods, respectively. The relative configuration of sapinofuranone C was assigned by X-ray diffraction analysis, whereas its absolute configuration was determined by applying the advanced Mosher's method to its 11-O-p-bromobenzoyl derivative. The same method was used to assign the absolute configuration to C-5 of diplopyrone B and to that of the hydroxyethyl of the side chain of diplobifuranylone C, respectively. The metabolites isolated were tested at 1 mg/mL on leaves of cork oak, grapevine cv. 'Cannonau', and tomato using the leaf puncture assay. They were also tested on tomato cuttings at 0.2, 0.1, and 0.05 mg/mL. Each compound was tested for zootoxic activity on Artemia salina L. larvae. The efficacy of sapinofuranone C and diplopyrone B on three plant pathogens, namely, Athelia rolfsii, Fusarium avenaceum, and Phytophthora nicotianae was also evaluated. In all phytotoxic assays only diplopyrone B was found to be active. It also showed strong inhibition on the vegetative growth of A. rolfsii and P. nicotianae. All metabolites were inactive in the assay performed for the zootoxic activity (A. salina) even at the highest concentration used (200 μg/mL). Diplopyrone B showed a promising antioomycete activity for the control of Phytophthora spp. also taking into account the absence of zootoxic activity.

The Mediterranean basin is recognized as a global biodiversity hotspot accounting for more than 25,000 plant species that represent almost 10% of the world's vascular flora. In particular, the maquis vegetation on Mediterranean islands and archipelagos constitutes an important resource of the Mediterranean plant diversity due to its high rate of endemism. Since 2009, a severe and widespread dieback and mortality of Quercus ilex trees and several other plant species of the Mediterranean maquis has been observed in the National Park of La Maddalena archipelago (northeast Sardinia, Italy). Infected plants showed severe decline symptoms and a significant reduction of natural regeneration. First studies revealed the involvement of the highly invasive wide-host range pathogen Phytophthora cinnamomi and several fungal pathogens. Subsequent detailed research led to a better understanding of these epidemics showing that multiple Phytophthora spp. were involved, some of them unknown to science. In total, nine Phytophthora species were isolated from rhizosphere soil samples collected from around symptomatic trees and shrubs including Asparagus albus, Cistus sp., Juniperus phoenicea, J. oxycedrus, Pistacia lentiscus and Rhamnus alaternus. Based on morphological characters, growth-temperature relations and sequence analysis of the ITS and cox1 gene regions, the isolates were identified as Phytophthora asparagi, P. bilorbang, P. cinnamomi, P. cryptogea, P. gonapodyides, P. melonis, P. syringae and two new Clade 6 taxa which are here described as P. crassamura sp. nov. and P. ornamentata sp. nov. Pathogenicity tests supported their possible involvement in the severe decline that is currently threatening the Mediterranean maquis vegetation in the La Maddalena archipelago.

During a study of the species of Botryosphaeriaceae associated with oak decline in Tunisia, a large collection of Diplodia strains were isolated from Quercus afares, Q. canariensis and Q. suber trees showing a progressive dieback of shoots and branches, trunk canker and exudates and collar rot. Most of the isolates were identified as Diplodia corticola, while two isolates from Q. canariensis were morphologically and phylogenetically (ITS and tef1-α sequences data) distinct from all other known species of Diplodia. They are described here as Diplodia quercivora sp. nov. In addition, phylogenetic analyses showed for the first time the existence of two distinct lineages within D. corticola. In artificial inoculation experiments, D. quercivora caused necrotic lesions on bark and wood of three Mediterranean oak species, Q. ilex, Q. pubescens and Q. suber. In particular, among the oak species tested, Q. pubescens was the most susceptible.