An investigation was carried out on the distribution and biodiversity of steinernematid and heterorhabdtid entomopathogenic nematodes (EPN) in nine regions of Italy in the period 1990-2010. More than 2000 samples were collected from 580 localities and 133 of them yielded EPN specimens. A mapping of EPN distribution in Italy showed 133 indigenous EPN strains belonging to 12 species: 43 isolates of Heterorhabditis bacteriophora, 1 of H. downesi, 1 of H. megidis, 51 of Steinernema feltiae, 12 of S. affine, 4 of S. kraussei, 8 of S. apuliae, 5 of S. ichnusae, 3 of S. carpocapsae, 1 of S. vulcanicum, 3 of Steinernema 'isolate S.sp.MY7' of 'S. intermedium group' and 1 of S. arenarium. Steinernematids are more widespread than heterorhabditids and S. feltiae and H. bacteriophora are the most commonly encountered species. Sampling sites were grouped into 11 habitats: uncultivated land, orchard, field, sea coast, pinewood, broadleaf wood, grasslands, river and lake borders, caves, salt pan and moist zones; the soil texture of each site was defined and the preferences of habitat and soil texture of each species was assessed. Except for the two dominant species, S. feltiae and H. bacteriophora, EPN occurrence tends to be correlated with a specific vegetation habitat. Steinernema kraussei, H. downesi and H. megidis were collected only in Sicily and three of the species recently described - S. apuliae, S. ichnusae and S. vulcanicum - are known only from Italy and seem to be endemic.
Abstract& Key message Cork oak decline is widespread in all its distribution range and seems to be triggered mainly by both mismanagement and unfavorable climatic factors. As a result, cork oak forests become susceptible to pest attack, which accelerates the onset of decline. Pest management strategies for this valuable and highly biodiverse ecosystem are examined in this review, taking into account the main insect pests and how their impact on cork oak forests is affected by climate change. While monitoring pests may provide the tools to predict the transition from endemic to epidemic insect populations, forestry practices (sanitary felling), biological control, and trapping are some of the most promising measures in protecting cork oak forests. & Context Over the last decades, cork oak (Quercus suber L.) decline has affected millions of trees throughout its distribution range. Cork oak is a typically Mediterranean species remarkably relevant for the biodiversity and landscape conservation of vast evergreen oak forests. Cork oak is also well known and highly valued for cork production. Climatic changes, management practices, and biotic factors, particularly plant pathogens and insect pests, play a decisive role in tree death and market devaluation of cork. & Aims Here, we review the major insect pests possibly involved in cork oak decline, while discussing pest management strategies. & Methods A survey of the current literature was performed to identify major insect pests affecting cork oak trees, as well as to establish the most promising pest management strategies under climate change. & Results Many authors seem to agree that the decline is triggered by both anthropogenic and abiotic factors, such as the mismanagement of cork oak forests and unfavorable climate (high temperatures and droughts). Consequently, trees become susceptible to pests and pathogens, which accelerate the onset of decline. & Conclusion Since a further increase in temperatures and droughts is expected, developing adequate management strategies to adapt cork oak trees to climate change, while simultaneously preventing and reducing insect pest attacks, is of foremost importance in the effort to conserve these unique and highly diverse ecosystems.Keywords Quercus suber . Cork oak decline . Climate change . Forest management Handling Editor: Aurelien SALLE Contribution of the co-authors Riziero Tiberi and Tiziana Panzavolta: conceived the idea, supervised literature reviewing, wrote the manuscript, and reviewed its final version. Manuela Branco: contributed to the writing of the manuscript, the reviewing of literature, and the revision of the final draft. Matteo Bracalini: contributed to the writing of the paper, the selection of literature, and the English revision of the manuscript. Francesco Croci: contributed to the writing of the manuscript and the assembling of related literature. All authors have read and approved the final manuscript.
1 Preliminary investigations were carried out on Dryocosmus kuriphilus Yasumatsu on Castanea sativa Miller in Tuscany to assess variations in gall characteristics in coppice and high forest at two crown heights (height < 2 or 2-6 m), influence of bud size and bud position on oviposition rates and susceptibility of three cultivars. 2 Gall size may depend on various factors, including wasp population density. In the present study area, small galls (with one or two cells) were the most numerous in 2008, whereas larger galls (with more than three cells) prevailed in 2009. 3 Dryocosmus kuriphilus oviposition occurrence was influenced by both bud size and bud position. Buds with eggs tended to be larger in size compared with bud without eggs, suggesting that D. kuriphilus females prefer to lay eggs in larger buds (approximately 6 mm 3 ) compared with smaller buds (approximately 3 mm 3 ). The mean number of eggs per bud tended to decrease from the apical bud toward the basal bud. 4 Three C. sativa cultivars, Carpinese, Fusca and Cesurone, were examined. Fusca grafts had significantly more galls compared with Carpinese and Cesurone, whereas Cesurone grafts had more larvae per bud compared with Carpinese and Fusca.Overall, the Carpinese cultivar may be less susceptible to D. kuriphilus galling compared with the Fusca and Cesurone cultivars.
The aim of this research was to assess the larval instar number of Pissodes castaneus (De Geer) and to facilitate the study of its biology by identifying a reliable method to determine the instar of individual larvae. The larvae of this weevil were collected in central Italy in 2004, and their head capsules were measured by means of a binocular microscope. Head capsule width and length data were analyzed using Hcap, a computer program that use the distribution of size measures to determine instar separation rules. To determine instar number, the Gaines and Campbell method, which represents the perfect geometric progression of size measures (Dyar's rule) by a regression line, was also used. This study identified four larval instars of P. castaneus and found that head capsule widths and lengths followed Dyar's rule and reliably distinguished instars.
Although mass trapping cannot be a definitive control measure, it is one of the few ones available to contain the destruction of millions of cubic metres of conifer forests perpetrated every year worldwide by bark beetles. However, using bark beetle aggregation pheromones during both monitoring and control programs may negatively affect other saproxylic insects. The aim of this study was to describe the response of both Ips sexdentatus and its saproxylic beetle associates, especially predators, to traps baited with a commercial blend of I. sexdentatus aggregation pheromone. Furthermore, the usefulness of adding pine volatiles, such as (−)‐α‐pinene and ethanol, to the pheromone was discussed. The commercial blend proved to be attractive to I. sexdentatus adults, both when used alone and together with pine volatiles. Pheromone attractiveness, however, was lessened by the addition of the volatiles. The pheromone blend proved to be attractive to Thanasimus formicarius, as well as to other predator species. Overall, although during our study, traps baited only with (−)‐α‐pinene and ethanol attracted some predator specimens, I. sexdentatus pheromone traps were more attractive. Our study confirms that calendar differences in flight activity between the bark beetle and its predators are substantial; therefore, they should be taken into account when planning control measures. According to our data, the commercial blend of I. sexdentatus pheromone seems to be the most effective, among the baits used, in catching I. sexdentatus adults, while reducing the impact on T. formicarius.
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