Elisabetta Feci

Copper complexes grafted to functionalized silica gel as wood preservatives against the brown rot fungus Coniophora puteana

Wood modification with siloxanes bearing amino groups with copper-linking function was carried out by a sol–gel process. Tetraethoxysilane (TEOS) and 3-aminopropyltriethoxysilane (APTES) were the main components. Two different procedures were followed: a two-step process (impregnation with the TEOS/APTES mixture followed by dipping into a copper sulphate solution) and a one-step process (impregnation with a homogeneous sol mixture of TEOS, APTES and copper (II) chloride). The obtained materials were characterized by infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and energy dispersive X-ray microanalysis. The determination of copper content before and after leaching was performed by atomic absorption spectroscopy. The efficacy against the brown rot fungus Coniophora puteana was tested by an accelerated procedure. SEM analyses showed that silicon penetrated into wood, while copper is effectively drawn into wood only in the one-step treatment. Copper fixation to the silica gel proved to be adequately strong. Both sol–gel treatments gave good protection against Coniophora puteana.

Polyamidoamines (PAAs) functionalized with siloxanes as wood preservatives against fungi and insects

Abstract A novel treatment based on polyamidoamines (PAAs) for the preservation of wood against fungi and insects with a broad protection functionality, low effective concentration, and low environmental impact has been developed. PAAs were synthesized by nucleophile addition of ethanolamine (EtA) and/or 3-aminopropyltriethoxysilane (APTES) to N,N′-methylene-bisacrylamide (MBA). The molar ratios in the tested formulation were: I) MBA:EtA=1:1; II) MBA:APTES=1:1; III) MBA:EtA:APTES=1:0.5:0.5. These formulations, characterized by ESI-MS, NMR, FT-IR, were tested against: (a) the wood decay fungi (Coniophora puteana, Coriolus versicolor, and Poria placenta); (b) the subterranean termite Reticulitermes lucifugus, and the drywood termite Kalotermes flavicollis; (c) the woodborer Stegobium paniceum. Tests in combination with leaching showed that formulation II and III can be utilized as fungal wood preservatives for use classes 2–3 (EN 335:2013). In addition, all PAAs formulations were equally effective in preserving wood against the subterranean termite, and formulation II was most effective against drywood termite. On the other hand, the formulation I showed good efficacy against S. paniceum.

Diagnostic Evaluation of Insect Attack on Existing Timber Structures: A Review of some Case Studies

The problem of wood-boring insect attacks is gaining greater interest in Italy today. Wood-boring insects (Coleoptera, termites) often cause both structural and aesthetic damage on wooden structures which can sometimes give rise to human health concerns. Possible causes of current insect infestations include the use of timber originating from plantations, as well as bad post-felling practices such as late harvesting and stocking in unsuitable places before final processing. In the past, these insects were not thought to pose an economic threat to timber in service in Italy, but, in recent years, they have become a problem. The aim of this paper is to report on case studies concerning the occurrence of these unusual wood-boring insects on timber in service and, on the basis of the Authors experience, to formulate an in situ inspection protocol. The species we are dealing with in the case studies are: Bostrichus capucinus, family Bostrichidae, associated with Lyctus spp. (Fam. Lyctidae) and Lymexylon navale, family Lymexylonidae, belonging to the group of the so-called ambrosia beetles or pinhole borers. All these species were found on hardwoods, where they had bored into the sapwood except for L. navale which was also able to bore into heartwood, causing major concerns about its potential danger to timber in service. A technical integrated approach in evaluating insect attacks on on-site timber elements is also described here. The assessment is based on different methods, i.e. visual inspection and acoustic detection. This procedure is proposed as a basis for the development of an intervention protocol in the early stages of infestation.

Nutritional requirements for larval development of the dry wood borer Trichoferus holosericeus (Rossi) in laboratory cultures

Despite the dangerousness of the dry wood-boring beetle Trichoferus holosericeus (Rossi) (=Hesperophanes cinereus (Villiers)) (Coleoptera: Cerambycidae), little is known about its biological and nutritional requirements. The aim of this research was therefore to investigate into the dietary preferences of this insect, in order to determine if carbohydrates can be considered as its main nutritional source, to clarify whether this cerambycid is specialised on hardwoods and finally to select a suitable diet for laboratory cultures. Different substrates were tested and the decay grade, as well as the survival of larvae, was recorded after 3 and 6 months. Chemical analyses were also carried out on excrements, residues of wood after larvae excavation and sound wood. Results indicated that T. holosericeus fed mainly on glucose and peptone added to an artificial diet, while on natural wood it preferred structural carbohydrates constituting the hemicelluloses and the non-crystalline cellulose. Furthermore, Scots pine sapwood had no toxic effect to the beetle. In terms of number and dimensions of emerged larvae, the artificial diet resulted to be the most suitable substrate for laboratory cultures of T. holosericeus among those tested.