Two different in-row soil management techniques were compared in the Olive Orchard Innovation Long-term experiment of the Council for Agricultural Research and Economics, Research Centre for Olive, Fruit, and Citrus Crops in Rome, Italy. Rows were managed with an in-row rotary tiller and with synthetic mulching using permeable polypropylene placed after cultivar Maurino olive trees planting. The effects of the two treatments were assessed through weed soil coverage and the growth of the olive trees. Results showed better agronomic performance associated with synthetic mulching. The weed control effect along the row of a young high-density olive orchard was higher with the synthetic mulching compared to hoeing. The effect of the synthetic mulching seemed to disappear when removed from the ground (spring 2023) since no significant differences were found for tree size and yield in the two tested in-row soil management systems at the end of 2023. Finally, the growth of the young olive trees (Trunk Cross Sectional Area, Height, and Canopy expansion) measured across the three years, was higher for the synthetic mulched row than the hoed one. The use of synthetic mulching along the row positively forced the vegetative growth of the young olive trees and anticipated the onset of fruit production compared to periodical hoeing: a significantly higher fruit production was registered three years after planting. Root diameter was higher under synthetic mulching one year after planting, and no differences were observed in the following sampling dates showing similar fluctuations linked to the seasonal growth pattern. The life cycle assessment and costing highlighted that the application of mulching had a higher eco- and economic-efficiency than the periodical in-row soil hoeing.

Xylella fastidiosa subsp. pauca (Xfp), a quarantine pathogen in the European Union, severely threatens Mediterranean olive production, especially in southern Italy, where Olive Quick Decline Syndrome (OQDS) has devastated Apulian olive groves. This study addresses the urgent need to identify resistant olive genotypes by monitoring 16 potentially tolerant genotypes over six years, assessing symptom severity and bacterial load. These genotypes, which survived in heavily infected areas, showed varied responses to Xfp; some maintained low symptom severity with minimal bacterial presence (high or undetectable Cq values), while others exhibited increased bacterial loads yet remained asymptomatic or showed limited canopy desiccation. SSR markers were used to investigate the genetic relationships among these genotypes and other widespread Mediterranean cultivars, showing genetic similarity with the resistant ones such as the Albanian Kalinjot and the Greek Leucocarpa, as well as with local Apulian cultivars, highlighting the potential of local and Mediterranean olive germplasm for Xfp resistance. This study integrates phenotypic responses with genetic knowledge to support the development of conservation strategies that will enhance the genetic diversity of Apulian olive cultivars. In addition, by focusing on the resilience of the different olive genotypes, this research aims to protect the traditional cultivars from the emerging threats, thus preserving the ecological and cultural heritage of the olive biodiversity of the Mediterranean region.

Diaporthe amygdali Delacr. is a phytopathogenic fungus of considerable agronomic importance, responsible for branch canker in almond (Prunus dulcis [Mill.] D.A. Webb) and peach (Prunus persica L.) trees. It represents a major phytosanitary threat to almond cultivation in Europe, particularly in Mediterranean regions. Almond is currently among the most rapidly expanding perennial crops, with cultivated areas increasing as a result of the introduction of new cultivars and the adoption of improved agronomic practices. The objectives of this study were to isolate and identify fungal pathogens from infected almond samples collected in France through multilocus phylogenetic analyses (ITS, tef1-α, his3, tub2, cal genes) combined with morphological characterization; evaluate the susceptibility of 18 almond genotypes, using ‘Ferragnès’ and ‘Texas’ as reference standards for susceptibility and tolerance, respectively; and compare three field inoculation methods. All isolates were identified as D. amygdali. The varietal screening identified marked differences in resistance among the tested cultivars. In particular, ‘Ferrastar’, ‘R1877’, ‘R1413’, and ‘R1542’ exhibited high levels of resistance, whereas ‘Tuono’, ‘Guara’, and ‘R1568’ showed susceptibility comparable to that of ‘Ferragnès’, which was used as the susceptible control. Among the inoculation methods evaluated, the mycelial plug technique proved to be the most consistent and reliable, outperforming both conidial suspension inoculation and the toothpick method coated with mycelium. These findings further confirm the genetic resistance of the cultivars ‘Ferrastar’ and ‘Ardèchoise’ to branch canker across different growing conditions, supporting their suitability for use in breeding and genetic improvement programs.

Diaporthe amygdali (anamorph Phomopsis amygdali) is a phytopathogenic fungus of considerable agronomic importance, responsible for branch canker in almond (Prunus dulcis) and peach (Prunus persica L.) trees, representing a major phytosanitary threat to almond cultivation in Europe—particularly in Mediterranean regions—where almond has become one of the most dynamic crops, with cultivated areas expanding rapidly as a result of new varietal introductions and improved agronomic practices. The objectives of this study were to: (i) isolate and identify fungal pathogens from infected almond samples collected in France through multilocus phylogenetic analyses (ITS, tef1-α, act, his3, tub2, cal genes) combined with morphological characterization; (ii) evaluate the susceptibility of 18 almond genotypes, using ‘Ferragnès’ and ‘Texas’ as reference standards for susceptibility and tolerance, respectively; and (iii) compare three field inoculation methods. All isolates were identified as D. amygdali. The varietal screening revealed notable resistance in cultivars ‘Ferrastar’, ‘R1877’, ‘R1413’, and ‘R1542’, whereas ‘Tuono’, ‘Guara’, ‘Ferragnès’, and ‘R1568’ were classified as susceptible. Among the inoculation techniques tested, the mycelial plug method proved to be the most consistent and reliable. The results confirm the presence of resistant genotypes, wich are useful for genetic improvement programs aimed at enancing resistance to related canker pathogens.

Polystigma amygdalinum the causal agent of Red Leaf Blotch (RLB), is responsible for one of the most important foliar diseases affecting almond [Prunus dulcis (Miller) D.A. Webb] in the Mediterranean Basin and the Middle East. The study is aimed at improving knowledge on RLB epidemiology and the role of environmental conditions in disease development. Field monitoring was conducted from 2022 to 2025 in three almond orchards located in Apulia (southern Italy) and characterized by different microclimatic conditions. A total of 39 cultivars, including Apulian local germplasm and international cultivars (‘Belona’, ‘Genco’, ‘Guara’, ‘Ferragnès’, ‘Filippo Ceo’, ‘Lauranne^® Avijor’, ‘Soleta’, and ‘Supernova’), were evaluated. Symptoms occurred from late spring to summer, resulting particularly severe on ‘Guara’ and ‘Lauranne^® Avijor’, whereas ‘Belona’, ‘Ferragnès’, ‘Genco’, and ‘Supernova’ exhibited the highest tolerance. To our knowledge, this is also the first report of RLB tolerance by ‘Filippo Ceo’, ‘Ficarazza’, ‘Centopezze’, and ‘Rachele piccola’ representing potential genetic resources for breeding programs. Moreover, these findings reinforced previous observations proving that RLB was less severe on medium-late and late cultivars. Disease incidence varied significantly among sites and years and was strongly associated with increased rainfall, higher relative humidity, and mild temperatures recorded in November, influencing disease occurrence in the following growing season. P. amygdalinum was consistently detected by qPCR in all RLB-affected tissues and, in some cases, from mixed early RLB + Pseudomonas-like symptoms. From some leaves with early RLB symptoms, P. amygdalinum was also successfully isolated in pure culture. Overall, our results provide clear evidence that P. amygdalinum is the sole fungal pathogen consistently associated with typical RLB symptoms in Apulia (southern Italy) and highlight important cultivar-dependent differences. Its frequent molecular detection in leaves showing atypical or mixed symptoms suggests unresolved epidemiological aspects requiring further investigation.