Leaf chlorosis, severe defoliation and wilt associated with root rot were observed on mature olive trees cv. Nera di Gonnos in an experimental orchard at Mirto Crosia (Calabria, southern Italy). An oomycete was consistently isolated from rotten roots of symptomatic olive trees. It was identified as Phytophthora bilorbang by morphological characters and sequencing of Internal Transcribed Spacer (ITS) regions of ribosomal DNA (rDNA). Pathogenicity was verified by inoculating potted two-month-old rooted cuttings of Olea europaea var. Nera di Gonnos in a soil infestation trial. P. bilorbang was re-isolated from roots of symptomatic, artificially inoculated olive cuttings to fulfill Koch’s postulates. This is the first report of P. bilorbang on O. europaea L. and on a species of the Oleaceae family worldwide.

Research Highlights: Protected natural areas are a reservoir of Phytophthora species and represent the most suitable sites to study their ecology, being less disturbed by human activities than other environments. Background and Objectives: The specific objective of this study was to correlate the diversity and distribution of Phytophthora species with the vegetation in aquatic, riparian and terrestrial habitats within a protected area in Eastern Sicily, Southern Italy. Materials and Methods: Environmental samples (water and soil) were sourced from two streams running through the reserve and six different types of vegetation, including Platano-Salicetum pedicellatae, the Sarcopoterium spinosum community, Myrto communis-Pistacietum lentisci, Pistacio-Quercetum ilicis,Oleo-Quercetum virgilianae and a gallery forest dominated by Nerium oleander (Natura 2000 classification of habitats). Phytophthora species were recovered from samples using leaf baiting and were classified on the basis of morphological characteristics and sequencing of internal transcribed spacer (ITS) regions of ribosomal DNA (rDNA). Results: As many as 11 Phytophthora species, within five different ITS clades, were identified, including P. asparagi, P. bilorbang, P. cryptogea, P. gonapodyides, P. lacustris, P. multivora, P. nicotianae, P. oleae, P. parvispora, P. plurivora and P. syringae. No Phytophthora species were found in the Sarcopoterium spinosum comm. Phytophthora asparagi, P. lacustris and P. plurivora were the prevalent species in the other five plant communities, but only P. plurivora was present in all of them. Overall aquatic species from clade 6 (100 out of 228 isolates) were the most common; they were recovered from all five types of vegetation, streams and riparian habitats. Phytophthora populations found in the Platano-Salicetum pedicellatae and Oleo-Quercetum virgilianae show the highest diversity, while no correlation was found with the physicochemical characteristics of the soil. Conclusions: The vegetation type and the aquatic or terrestrial habitat were identified as major environmental factors correlated with the diversity of Phytophthora communities in this reserve.

This study was aimed to characterize the secondary metabolites produced by four Colletotrichum species, C. acutatum, C. gloeosporioides, C. godetiae and C. karsti, both in vitro, on potato dextrose agar (PDA) and oatmeal agar (OA), and during the infection process of fruits of four olive cultivars differing in susceptibility to anthracnose, 'Coratina' and 'Ottobratica', both susceptible, 'Frantoio' and 'Leccino', both resistant. The metabolites were extracted from axenic cultures after seven days incubation and from olives inoculated singularly with each Colletotrichum species, at three different times, 1, 3 and 7 days post inoculation (dpi). They were identified using the UHPLC-QTOF-MS analysis method. In total, as many as 45 diverse metabolites were identified. Only 10 metabolites were present in both fruits and axenic cultures while 19 were found exclusively on olives and 16 exclusively in axenic cultures. The identified metabolites comprised fatty acid, phenolics, pyrones, sterols, terpenes and miscellaneous compounds. Each Colletotrichum species produced a different spectrum of metabolites depending on the type of matrices. On artificially inoculated olives the severity of symptoms, the amount of fungal secondary metabolites and their number peaked 7 dpi irrespective of the cultivar susceptibility and the virulence of the Colletotrichum species.

Paulownia species are fast growing trees native to China, which are being grown in managed plantings in several European countries for the production of wood and biomasses. In 2018, wilting, stunting, leaf yellowing, and collapse, as a consequence of root and crown rot, were observed in around 40% of trees of a 2-year-old planting of Paulownia elongata × P. fortunei in Calabria (Southern Italy). Two species of Phytophthora were consistently recovered from roots, basal stem bark, and rhizosphere soil of symptomatic trees and were identified as Ph. nicotianae and Ph. palmivora on the basis of both morphological characteristics and phylogenetic analysis of rDNA ITS sequences. Koch’s postulates were fulfilled by reproducing the symptoms on potted paulownia saplings transplanted into infested soil or stem-inoculated by wounding. Both Phytophthora species were pathogenic and caused root rot and stem cankers. Even though P. palmivora was the only species recovered from roots of naturally infected plants, in pathogenicity tests through infested soil P. nicotianae was more virulent. This is the first report of Phytophthora root and crown rot of a Paulownia species in Europe. Strategies to prevent this emerging disease include the use of healthy nursery plants, choice of well-drained soils for new plantations, and proper irrigation management.

Olive trees are a cornerstone of Mediterranean agriculture but face significant threats from diseases such as Verticillium wilt and olive anthracnose. These diseases, caused by Verticillium dahliae and Colletotrichum spp., respectively, result in significant economic losses and degrade olive oil quality. While traditional chemical treatments present environmental risk, sustainable alternatives such as biological control agents (BCAs) are gaining attention. Epicoccum nigrum, an antagonistic fungus, has shown potential as a BCA due to its production of antimicrobial secondary metabolites. This study aimed to observe whether E. nigrum has an antagonistic ability against V. dahliae and C. acutatum, and to elucidate the metabolic interactions between these fungi using NMR-based metabolomics. E. nigrum showed inhibitory effects on the growth of C. acutatum and V. dahlia of 44.97% and 38.73% respectively. Metabolomic profiling revealed distinct biochemical responses in E. nigrum, V. dahliae, and C. acutatum under mono- and dual-culture. Multivariate statistical analysis highlighted the metabolic shifts in mycelia and identified the primary metabolites, such as glutamine, 4-aminobutyrate, and phenylalanine that are involved in adaption for survival in stress conditions such as the presence of a competitor. The results could be important for a better understanding of the primary fungal metabolism, which is still poorly characterized. Further investigation is needed, but these results suggest that E. nigrum could serve as a BCA, offering a more sustainable approach to managing olive diseases.

Evaluation of environmental and economic effectiveness of the Cross Compliance 4.3 Standards "Maintenance of olive groves and vineyards in good vegetative conditions"