Research Highlights: Pestalotiopsis pini sp. nov. is an emerging pathogen on stone pine, Pinus pinea L., in Portugal. Background and Objectives: Stone pine is one of the most important forest tree species in Portugal and in the whole Mediterranean basin. Pestalotiopsis species are common endophytes, saprobes or pathogens in a variety of hosts and environments. The objective of the present study was to identify the Pestalotiopsis species associated with the symptomatic stone pine trees. Materials and Methods: Samples of stone pine trees showing shoot blight and stem necrosis were obtained from stone pine orchards and urban areas in Portugal, and the isolated Pestalotiopsis species were identified based on morphology and combined ITS, TEF and TUB DNA sequence data. Artificial inoculations on one-year-old stone pine seedlings were performed with the two species most frequently found in association with shoot blight disease. Results: Five Pestalotiopsis spp. were isolated. A taxonomic novelty, Pestalotiopsis pini is described, representing a new pathogen for stone pine. Conclusions: Pestalotiopsis species may represent a threat to the health of pine forests in the Mediterranean basin. Future research should be done in order to increase our knowledge about the potential impact of pestalotioid species in stone pine, in order to develop management strategies against these pathogens.

Fusarium circinatum, the causative agent of pine pitch canker disease, is a pathogenic fungus that poses a significant threat to pine forests globally. It infects various Pinus species, causing resinous cankers, needle discoloration, and tree death. The disease severely impacts forest ecosystems, necessitating cost-effective and environmentally friendly management strategies. Contaminated pine seeds and seedlings are the main pathways for introducing this fungus to disease-free areas. To mitigate this disease and prevent its spread, it is crucial to implement new processes in forest plant production systems that align with the existing conditions of forest nurseries, ensuring effective and sustainable management. With this in mind, a national collaborative study involving 14 Portuguese partners was initiated to develop new prevention and mitigation strategies. In this work, four different treatments—MennoFlorades, Captan, ethanol, and hot water—were tested for their ability to eliminate F. circinatum from contaminated Pinus seeds in vitro. The most effective treatments were selected for further in vitro assays and real-context nursery germination trials to assess their impacts on seed germination, plant production, and certification. MennoFlorades, Captan, and hot water were tested in the nursery, with hot water showing the most promising results due to its negligible impact on seedlings, eco-friendly nature, ease of implementation, and cost-effectiveness. These findings offer promising prospects for preventing pine pitch canker outbreaks in nurseries and, consequently, in forests.

Pine pitch canker is one of the much concerning forest diseases in Europe, affecting both adult and young plant hosts. Substrates used in nurseries, especially the ones incorporating Fusarium circinatum host plant residues, such as pine bark, may represent a vehicle for the spread of the fungus. The present study tested the efficacy of solarization on the elimination of F. circinatum inoculum from an artificially inoculated substrate, after three and seven weeks of treatment application, compared with a non- solarized control treatment. The results show a reduction of the viable inoculum density of F. circinatum from the substrate after seven weeks, which suggests that substrate solarization may be a process to minimize biotic risks in a nursery.

The species in genus Amanita section Amidella form a well-defined clade, but some taxa remain difficult to discriminate. In particular, the concept of Amanita valens (E.-J. Gilbert) Bertault remains controversial. To understand the phylogenetic placement of a set of collections from South Portugal with a novel nrDNA barcode, we have obtained nrDNA sequences for previously unassessed type collections. The taxon formerly described as Amanita curtipes f. pseudovalens Neville & Poumarat is interpreted as a separate species, Amanita pseudovalens (Neville & Poumarat) Arraiano-Castilho et al . comb. et stat. nov., and is genetically indistinct from the Portuguese collections, thus clarifying their taxonomic context. However, our collections are morphologically and ecologically distinct (respectively, ellipsoid to oblong basidiospores and association with Cistus on acidic schist soils), and are proposed as a new variety, Amanita pseudovalens var. tartessiana Arraiano-Castilho et al .. These developments also enable a better diagnosis of Amidella taxa in Europe, a progress that is most decisive for the late Winter to Spring season collections, and identification keys are proposed. However, the co-occurrence and morphological similarity of the new variety, in comparison with the prized edible Amanita ponderosa Malençon & Heim, could leave some collections of either taxa unresolved. Thus, a molecular marker approach was developed, to provide a clear and cost-effective identification aid to complement the keys. The proposed diagnostic tools can be applied toward a review of European Amidella taxa chorology from existing records, conserved materials, and future collections. Evolutionary convergence may contribute to the determination difficulties in the Amidella clade.