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Biscogniauxia species are opportunistic pathogens primarily associated with Quercus species dieback in the Mediterranean basin. Among these species, Biscogniauxia mediterranea stands out as the only species previously documented in Tunisia, affecting Quercus suber and Erica multiflora. This study unveils a novel finding, reporting the presence of Biscogniauxia rosacearum on Strawberry trees in Tunisia. The identification of B. rosacearum isolates was confirmed based on DNA sequence data (ITS, TUB2 and ACT) and morphological traits. Artificial inoculation trials on leaves confirmed the pathogenicity of the fungus towards Arbutus unedo. This finding emphasizes the significance of implementing proactive measures to effectively combat this pathogen because of the polyphagous nature of Biscogniauxia species that raises concerns about its potential spread within vulnerable hosts in Tunisian oak forests. [ABSTRACT FROM AUTHOR]

Biscogniauxia mediterranea has long been recognized as the causal agent of charcoal canker disease of Quercus species. It has been considered to be highly involved in cork oak decline in the Mediterranean region. In this study, a collection of B. mediterranea strains was isolated from declining cork oak trees in three cork oak forests in Tunisia. Among them, nine representative isolates were subjected to genetic polymorphism analysis based on ITS and tef1-α sequences showing a highly significant haplotype diversity. Pathogenicity tests of these isolates revealed a highly pathogenic effect towards stems which differed significantly between isolates. Although, they were less aggressive toward leaves. Nevertheless, the Mantel test indicated the absence of a significant correlation between the genetic and pathogenic variability. [ABSTRACT FROM AUTHOR]

Cork oak decline and mortality are increasingly prevalent in the Mediterranean basin. This require particular attention due to the great economic value of this plant species. Biscogniauxia mediterranea is one of the most common pathogens highly associated to cork oak decline. However, documentation on its incidence is still scarce, especially in Tunisia. In this context, our research aimed at detecting its presence in Tunisian natural cork oak forests and assessing factors influencing its occurrence. Investigations were carried out in six forests in northwestern Tunisia. Dendrometric parameters of trees, ecological factors (rainfall, temperature, and altitude), and the presence of B. mediterranea as pathogen were determined. The endophytic presence of this fungus was also established. It was detected in all investigated forests, with significantly different frequencies, and was reported to be related to the dendrometric structure of the cork oak trees. On the other hand, the presence of B. mediterranea as pathogen was only detected in Ain Beya and Ain Sarouia forests. It was very limited with 4% of trees per site showing the disease signs. In conclusion, measures to prevent the dispersal of B. mediterranea throughout other cork oak forests shall be implemented in order to conserve such valuable forest resources. [ABSTRACT FROM AUTHOR]

Background and Aims Oaks are the foundation and dominant tree species of most Mediterranean forests. As climate models predict dramatic changes in the Mediterranean basin, a better understanding of the ecophysiology of seed persistence and germination in oaks could help define their regeneration niches. Tunisian oaks occupy distinct geographical areas, which differ in their rainfall and temperature regimes, and are thus a valuable model to investigate relationships between seed traits and species ecological requirements. Methods Seed morphological traits, desiccation sensitivity level, lethal freezing temperature, embryonic axis and cotyledon sugar and lipid composition, and seed and acorn germination rates at various constant temperatures were measured in Quercus canariensis , Q. coccifera , Q. ilex and Q. suber , using seeds sampled in 22 Tunisian woodlands. Key Results Only faint differences were observed for desiccation sensitivity in the oak species studied. By contrast, the species differed significantly in sensitivity to freezing, germination rates at low temperature and base temperature. Quercus ilex and Q. canariensis , which occur at high elevations where frost events are frequent, showed the lowest freezing sensitivity. A significant correlation was found between hexose contents in the embryonic axis and freezing tolerance. Significant interspecific differences in the time for seeds to germinate and the time for the radicle to pierce the pericarp were observed. The ratio of pericarp mass to acorn mass differed significantly among the species and was negatively correlated with the acorn germination rate. Quercus coccifera , which is frequent in warm and arid environments, showed the highest acorn germination rate and synchrony. Conclusions Seed lethal temperature, seed germination time at low temperatures, the ratio of pericarp mass to acorn mass and the embryonic axis hexose content appeared to be key functional traits that may influence the geographical ranges and ecological requirements of Mediterranean oaks in Tunisia. [ABSTRACT FROM AUTHOR]

The early spring folivore green oak leaf roller moth, Tortrix viridana, is one of the most harmful pests of Palaearctic oaks. The young larvae develop inside flushing buds and therefore require moth egg-hatching and budburst of their host plant to be synchronized. The aim of this study was to understand which factors (geographical distances, oak species, oak leaf phenology and timing of moth egg-hatching) influence the genetic structure of the moth. We performed multilocus analyses (COI and COII mitochondrial genes and eight nuclear microsatellites) on 30 populations from key forest districts in Sardinia and other Mediterranean localities. Both mitochondrial and nuclear markers detected a genetic divergence among populations that were separated by long distances and/or wide sea straights (Sardinia–Corsica vs. Tunisia vs. Italian peninsula–Sicily). Mitochondrial variation was divided into two major haplogroups relating to early or late egg-hatching behaviour, which was dependent on adaptation to specific oak budburst phenologies. On a regional scale, AMOVA tests showed the highest fixation indexes when populations were grouped according to early or late egg-hatching, whereas oak leaf phenology [deciduous (pubescent oak) or evergreen (holm oak and cork oak)] was the main factor in structuring populations on a larger Mediterranean scale. Furthermore, we demonstrated evidence for non-random patterns of gene flow mediated by male-biased dispersal, with females as the philopatric sex. [ABSTRACT FROM AUTHOR]

Acorns of Quercus suber were collected in December 2018 from northwestern Tunisia and stored at laboratory. Larvae of pest emerged from infested acorns were used for molecular analysis. In the light of these data, this paper presents the first report of Cydia rymarczki Varenne & Nel, 2013, Cydia splendana (Hübner, 1799) and Curculio glandium Marsham, 1802, as pests of Quercus suber's acorns for Tunisia. [ABSTRACT FROM AUTHOR]

Platypus cylindrus is an important wood borer of cork oak trees (Quercus suber) in the Mediterranean region, namely Portugal, Morocco and Algeria where its presence has drastically increased in the past few decades. On the contrary, the insect is not a relevant pest in Tunisia. The aim of this work is to analyze morphological and genetic differences among Tunisian and Portuguese populations in order to understand their role in the diverse population dynamics (e.g., aggressiveness) of the insect. The information could be used as a novel tool to implement protective measures. Insects were collected from cork oak stands in Tunisia (Ain Beya, Babouch and Mzara) and Portugal (Chamusca and Crato). Morphological traits of female and male mycangial pits were determined, using scanning electron microscopy but no significant differences were found. Genetic differences were analyzed using nuclear (internal simple sequence repeat polymerase chain reaction) and mitochondrial (cytochrome oxidase I (COI)) molecular markers. The results showed a very low level of intraspecific polymorphism and genetic diversity. The alignment of COI sequences showed high percentage of identical sites (99%) indicating a very low variation in nucleotide composition. Other variables related with the ecology of the insect and its associated fungi must be studied for a better understanding of the differences in the insect population's dynamic in Mediterranean countries. [ABSTRACT FROM PUBLISHER]

Ambrosia beetles, including Platypus cylindrus, commonly act as vectors of Ophiostomatales. In an investigation of fungi associated with P. cylindrus, several species of Ophiostomatales were identified, including two species of Ophiostoma s. str. These two species were characterized based on comparisons of DNA sequences of the internal transcribed spacer regions including the 5.8S gene of rDNA and β‐tubulin gene. Two distinct clades were discernable in the phylogenetic trees, supported by high bootstrap values. One clade included the species Ophiostoma tsotsi, reported herein for the first time in Tunisia, and the species Ophiostoma quercus. [ABSTRACT FROM AUTHOR]