Performance of European Wood Species in Above Ground Situations After 10 Years of Weathering: Evidence of a Positive Impact of Proper Design

. Most of European native wood species used outdoors are expected to last less than 10 years if left untreated and exposed to severe environmental conditions such as high humidity and biological agents. However, the current classification of wood’s natural durability based on EN standards does not fully reflect real end-use conditions, often underestimating wood’s performance in use. In addition, the importance of design details and the role they play in enhancing service life, especially in the case of outdoor applications, is often neglected. With the aim of evaluating the positive impact of proper design on wood’s service life, large-scale experimental devices, manufactured according to different designs (water draining / trapping) from six native wood species, were installed in 2009 in two French cities benefiting from different climatic conditions (oceanic / continental). The results of the evaluation carried out after 10 years of natural weathering demonstrated that (1) significant differences in the ability to withstand decay over time exist depending on the selected design details and the climatic conditions encountered in the experimental fields; (2) high variability in the resistance of non-durable spruce and poplar wood against fungal decay was noticed for each tested design, but with an unexpected high percentage of elements performing very well; (3) the moderately durable heartwood of larch, maritime pine and Douglas fir was mostly unaffected by decay even under severe conditions of exposure to rain (decking modules), suggesting these species may have greater value for outdoor applications without any preservative biocidal treatment than previously assumed

Évolution, génétique et structure coloniale du termite souterrain Reticulitermes grassei (Clément)

La présence de termites souterrains en France est connue depuis le 17ème siècle. L'Aquitaine est l'une des régions les plus fortement infestées, et Reticulitermes grassei, l'espèce mise en cause est difficile à éradiquer. La société Dow Agrosciences s'est ainsi associée au CNRS dans le but d'optimiser l'efficacité de son système de traitement par appâts. Pour comprendre les origines de l'établissement de cette espèce en France, nous avons retracé son histoire évolutive depuis le berceau ibérique, où les populations ancêtres se sont réfugiées pendant les glaciations du Quaternaire, jusqu'aux forêts et agglomérations charentaises où les colonies de R. grassei sévissent actuellement. Une étude phylogéographique combinant des approches à la fois écologiques, comportementales, chimiques et génétiques, nous a permis de comprendre les routes de migration empruntées par les populations pionnières de R. grassei, et leurs conséquences sur la structuration génétique des populations établies dans différentes aires géographiques. Nous sommes également parvenus à rapprocher cette espèce d'une autre espèce ibérique, R. banyulensis, et à comprendre quand et comment ces deux espèces parentes ont divergé. L'étude génétique de la structure coloniale de R. grassei en France et en Espagne a permis d'estimer l'étendue des colonies en milieu naturel, et leurs capacités d'expansion via la production de reproducteurs secondaires. Les colonies de R. grassei s'organisent en types familiaux très variables, qui sont fonction du nombre de reproducteurs présents dans la colonie, ainsi que de leur apparentement génétique. Un suivi de la survie et du développement de colonies artificielles, a démontré l'aptitude de cette espèce à redémarrer une nouvelle colonie à partir de quelques dizaines d'ouvriers. L'originalité du cycle reproducteur des termites, leur longue espérance de vie et leurs potentialités ontogéniques uniques, sont autant de facteurs qui favorisent leur installation et leur pérennité dans des zones habitées, et ce même en présence de traitements chimiques.Subterranean termites have been known to occur in France since the 17th century. Aquitaine, one of the most infested French regions, is inhabited by the Reticulitermes grassei species, which is particularly tricky to eradicate. The company Dow Agrosciences initiated a project together with the CNRS that aimed to clarify the patterns of this species biology in order to optimise the use of the baiting system technology. In order to elucidate the historical origins of the infestation by termites in France, we first inferred the evolutionary history of R. grassei. We demonstrated that ancestral populations survived in the south of the Iberian Peninsula during the Quaternary glaciations, before expanding towards northern areas, successively colonising central and northern Spain, and finally France. A phylogeographical study of R. grassei populations combining ecological, behavioural, chemical and genetic approaches enabled us to identify the migration routes followed by the pioneer populations and their consequences on the present genetic structure of populations established in geographically distinct areas. We also demonstrated the phylogenetic proximity that exists between R. grassei and R. banyulensi, another Iberian species. The study of subterranean termite's social and colonial organisation provided new insights on their ability to adapt to urban constraints. The identification of the genetic structure of R. grassei colonies collected across France and Spain helped to understand their spatial distribution under natural conditions and on their ability to extend through the production of secondary reproductives. R. grassei colonies can be divided in simple and complex families, based on the number and on the genetic relatedness of the reproductives. By investigating the survival and the development of laboratory colonies, we demonstrated this species' ability to restart an new colony in few months from a few dozens of isolated workers which can differentiate into secondary neotenic reproductives. The originality of termite's life cycle, their good lifespan and their ontogenetic potentialities, unique among social insects, are all factors that serve their settlement and their persistence in human inhabited areas, even the ones that are protected with chemical treatments.TOURS-BU Sciences Pharmacie (372612104) / SudocSudocFranceF

Update on the distribution of termites and other wood-boring insects in Europe

International audienc

Insulation Materials Susceptibility to Biological Degradation Agents: Molds and Subterranean Termites

Insulation materials are fundamental for decreasing energy losses and guaranteeing thermal and acoustic comfort in buildings, which may significantly contribute to decreasing the energy consumption related with poor thermal building conditions. These insulation materials should have a low susceptibility to biological degradation agents to decrease the risks of degradation of other construction materials, as well as decrease possible health risks related with the development of noxious biological degradation agents regarding indoor air quality, for example, or decrease possible structural risks posed by those agents. The present study aimed at evaluating the susceptibility of several insulation materials to mold growth and subterranean termites’ attack. Insulation materials, including expanded polystyrene (EPS), mineral wool (MW), and expanded cork agglomerate (ICB), were tested against mold development, using maritime pine as a control. Three types of inoculations were made: (1) natural indoor inoculation; (2) artificial inoculation using Aspergillus niger and Penicillium funiculosum; and (3) artificial inoculation using Aureobasidium pullulans. The susceptibility of the insulation materials referred to, plus wood/glass fiber (WGF), was evaluated for two subterranean termite species: Reticulitermes grassei and Reticulitermes flavipes. The expanded cork agglomerate showed a higher susceptibility to molds than the other insulation materials tested. The remaining materials revealed a good performance, showing no growth or traces of growth of molds. All the materials tested showed susceptibility to subterranean termites, with both species being able to cross them to obtain access to the wood. However, wood/glass fiber showed a negative effect, which translated into lower survival rates and attack degrees of the wood. Some tested materials showed a good resistance to the development of biological degradation agents, namely an organic material (coconut fiber), a composite of organic and inorganic materials (WGF), and an inorganic material (EPS). These results indicate that it is possible to pursue the development of innovative and effective insulation materials with a low susceptibility to biological degradation agents, regardless of their organic or inorganic origin.Validerad;2023;Nivå 2;2023-10-18 (joosat);CC BY 4.0 LicenseFunder: LNEC’ P2I, project ConstBio</p

Methods for recovering microorganisms from solid surfaces used in the food industry: a review of the literature

Various types of surfaces are used today in the food industry, such as plastic, stainless steel, glass, and wood. These surfaces are subject to contamination by microorganisms responsible for the cross-contamination of food by contact with working surfaces. The HACCP-based processes are now widely used for the control of microbial hazards to prevent food safety issues. This preventive approach has resulted in the use of microbiological analyses of surfaces as one of the tools to control the hygiene of products. A method of recovering microorganisms from different solid surfaces is necessary as a means of health prevention. No regulation exists for surface microbial contamination, but food companies tend to establish technical specifications to add value to their products and limit contamination risks. The aim of this review is to present the most frequently used methods: swabbing, friction or scrubbing, printing, rinsing or immersion, sonication and scraping or grinding and describe their advantages and drawbacks. The choice of the recovery method has to be suitable for the type and size of the surface tested for microbiological analysis. Today, quick and cheap methods have to be standardized and especially easy to perform in the field

Subterranean termite phylogeography reveals multiple postglacial colonization events in southwestern Europe

International audienc

Methods for recovering microorganisms from solid surfaces used in the food industry: a review of the literature

International audienceVarious types of surfaces are used today in the food industry, such as plastic, stainless steel, glass, and wood. These surfaces are subject to contamination by microorganisms responsible for the cross-contamination of food by contact with working surfaces. The HACCP-based processes are now widely used for the control of microbial hazards to prevent food safety issues. This preventive approach has resulted in the use of microbiological analyses of surfaces as one of the tools to control the hygiene of products. A method of recovering microorganisms from different solid surfaces is necessary as a means of health prevention. No regulation exists for surface microbial contamination, but food companies tend to establish technical specifications to add value to their products and limit contamination risks. The aim of this review is to present the most frequently used methods: swabbing, friction or scrubbing, printing, rinsing or immersion, sonication and scraping or grinding and describe their advantages and drawbacks. The choice of the recovery method has to be suitable for the type and size of the surface tested for microbiological analysis. Today, quick and cheap methods have to be standardized and especially easy to perform in the field