Spruce Resin Research Articles

Can larval Osmia bees (Megachilidae) tolerate conifer resin volatiles?

Some bees of the Megachilidae, particularly anthidiines, collect plant resins to partition, plug and sometimes line their nest cells. Adult females possess putative morphological, behavioral and perhaps exocrine adaptations for resin harvest, transport and handling. Their eggs and larvae later experience volatiles from the degassing resin, but are they specially adapted to tolerate or detoxify the monoterpenes and other volatiles? To answer this question, eggs and larvae of a megachilid mason bee that builds with mud, Osmia lignaria, were chronically exposed to volatiles emanating from fresh pine and spruce resins placed in their closed brood cells. Although their eggs and larvae do not normally encounter volatiles emanating from pine or spruce resin, they survived without ill effect. Therefore, no adaptive hypothesis needs to be invoked to explain resin volatile tolerance by immatures of resin-using anthidiine and Megachile bees. I briefly discuss potential implications for some other brood cell occupants.

Low-field, not low quality: 1D simplification, selective detection, and heteronuclear 2D experiments for improving low-field NMR spectroscopy of environmental and biological samples.

Understanding environmental change is challenging and requires molecular-level tools to explain the physicochemical phenomena behind complex processes. Nuclear magnetic resonance (NMR) spectroscopy is a key tool that provides information on both molecular structures and interactions but is underutilized in environmental research because standard "high-field" NMR is financially and physically inaccessible for many and can be overwhelming to those outside of disciplines that routinely use NMR. "Low-field" NMR is an accessible alternative but has reduced sensitivity and increased spectral overlap, which is especially problematic for natural, heterogeneous samples. Therefore, the goal of this study is to investigate and apply innovative experiments that could minimize these challenges and improve low-field NMR analysis of environmental and biological samples. Spectral simplification (JRES, PSYCHE, singlet-only, multiple quantum filters), selective detection (GEMSTONE, DREAMTIME), and heteronuclear (reverse and CH3/CH2/CH-only HSQCs) NMR experiments are tested on samples of increasing complexity (amino acids, spruce resin, and intact water fleas) at-high field (500 MHz) and at low-field (80 MHz). A novel experiment called Doubly Selective HSQC is also introduced, wherein 1H signals are selectively detected based on the 1H and 13C chemical shifts of 1H-13C J-coupled pairs. The most promising approaches identified are the selective techniques (namely for monitoring), and the reverse and CH3-only HSQCs. Findings ultimately demonstrate that low-field NMR holds great potential for biological and environmental research. The multitude of NMR experiments available makes NMR tailorable to nearly any research need, and low-field NMR is therefore anticipated to become a valuable and widely used analytical tool moving forward.

Growth, development and meat productivity of steers when using a biostimulator of plant origin

Many scientists note that there are plants that can stimulate not only feed intake, but also endogenous secretion, may have antimicrobial activity, many herbs are valuable in the prevention of the body. Of course, the use of herbal supplements in various forms requires constant monitoring, taking into account the accuracy of dosages, this is especially important when regular intake is considered. Currently, a new feed additive has been developed – a biostimulator of plant origin. The biostimulator includes: yarrow – 20 %, dioecious nettle – 20 %, blueberry leaves – 20 %, medicinal sage -18 %, St. John’s wort – 17 %, common tansy – 3 % and spruce resin – 2 %. The purpose of the work was to study the growth, development and meat productivity of steers when using a biostimulator of plant origin. Experimental studies were carried out in the breeding farm of the agricultural complex “Zarya” in the Mozhginsky district of the Udmurt Republic. The objects of research were steers of Black-and-White breed. The control group of steers received the main farm ration and the steers of the 1st and 2nd experimental groups in addition to the main ration received a daily biostimulator of plant origin in the amount of 0,15 and 0,30 g per 1 kg of live weight. It was found as a result of research that when using the biostimulator of plant origin in the amount of 0,30 g per 1 kg of live weight during the preweaning period in the ration of fattening steer, the prime-cost of live weight gain for the entire rearing period decreases, while the profitability of beef production increases by 8,2 abs.% in relation to the control group of steers.

Modification of poly(L-lactic acid)-based films and evaluation of physical and antibacterial properties by using multivariate data analysis

The aim of this study is to prepare new packaging materials with improved physical and antimicrobial properties that prevent the growth of microorganisms. Poly(L-lactic acid) (PLA) based packaging films were prepared by the solvent-casting method using spruce resin (SR), epoxidized soybean oil, an essential oil mixture (calendula and clove oil), and silver nanoparticles (AgNPs). The AgNPs were synthesized by the polyphenol reduction method, using spruce resin dissolved in methylene chloride. The prepared films were tested for antibacterial activity and physical properties, such as tensile strength (TS), elongation at break (EB), elastic modulus (EM), water vapor permeability (WVP), and UV-C blocking effect. The addition of SR decreased the water vapor permeation (WVP) of the films, whereas the addition of essential oils (EOs) increased this property due to their higher polarity. The morphological, thermal, and structural properties were characterized using SEM, UV–Visible spectroscopy, FTIR, and DSC. The agar disc well method showed that SR, AgNPs, and EOs imparted antibacterial activity to the PLA-based films against Staphylococcus aureus and Escherichia coli. Multivariate data analysis tools, such as principal component and hierarchical cluster analysis, were used to discriminate PLA-based films by simultaneously evaluating their physical and antibacterial properties.

Conifer-killing bark beetles locate fungal symbionts by detecting volatile fungal metabolites of host tree resin monoterpenes.

Outbreaks of the Eurasian spruce bark beetle (Ips typographus) have decimated millions of hectares of conifer forests in Europe in recent years. The ability of these 4.0 to 5.5 mm long insects to kill mature trees over a short period has been sometimes ascribed to two main factors: (1) mass attacks on the host tree to overcome tree defenses and (2) the presence of fungal symbionts that support successful beetle development in the tree. While the role of pheromones in coordinating mass attacks has been well studied, the role of chemical communication in maintaining the fungal symbiosis is poorly understood. Previous evidence indicates that I. typographus can distinguish fungal symbionts of the genera Grosmannia, Endoconidiophora, and Ophiostoma by their de novo synthesized volatile compounds. Here, we hypothesize that the fungal symbionts of this bark beetle species metabolize spruce resin monoterpenes of the beetle's host tree, Norway spruce (Picea abies), and that the volatile products are used as cues by beetles for locating breeding sites with beneficial symbionts. We show that Grosmannia penicillata and other fungal symbionts alter the profile of spruce bark volatiles by converting the major monoterpenes into an attractive blend of oxygenated derivatives. Bornyl acetate was metabolized to camphor, and α- and β-pinene to trans-4-thujanol and other oxygenated products. Electrophysiological measurements showed that I. typographus possesses dedicated olfactory sensory neurons for oxygenated metabolites. Both camphor and trans-4-thujanol attracted beetles at specific doses in walking olfactometer experiments, and the presence of symbiotic fungi enhanced attraction of females to pheromones. Another co-occurring nonbeneficial fungus (Trichoderma sp.) also produced oxygenated monoterpenes, but these were not attractive to I. typographus. Finally, we show that colonization of fungal symbionts on spruce bark diet stimulated beetles to make tunnels into the diet. Collectively, our study suggests that the blends of oxygenated metabolites of conifer monoterpenes produced by fungal symbionts are used by walking bark beetles as attractive or repellent cues to locate breeding or feeding sites containing beneficial microbial symbionts. The oxygenated metabolites may aid beetles in assessing the presence of the fungus, the defense status of the host tree and the density of conspecifics at potential feeding and breeding sites.

Pinoresinol stimulates keratinocyte proliferation and downregulates TNF-α secretion in peripheral blood mononuclear cells: An experimental in vitro study.

Natural coniferous resins are used in traditional medicine for the treatment of skin wounds. Coniferous wood resins ("callus" resin) are a mixture of abietic (resin) acids, lignans such as pinoresinol, and p-coumaric acid. The wound-healing properties of resins are thought to be related to their antimicrobial properties, but also to their effects on cell proliferation and inflammation. The purpose of this study was to identify and investigate the effects of novel aqueous dispersions of resin and its main components in the proliferation of human primary keratinocytes in vitroand in the expression of proinflammatory cytokines in human peripheral blood mononuclear cells. The proliferation studies were performed under low and high calcium conditions with or without added growth stimulators at the time points of 2and 6 days using AlamarBlue Cell Viability Reagent. The cytokine release assay was carried out by incubating the cells with the test articles for 18 h, after which the levels of tumor necrosis factor-α(TNF-α),interleukin-1β (IL-1β), IL-6, and IL-8 were measured in the supernatant by enzyme-linked immunosorbent assay. Resin and the purified lignan PINO, but not p-coumaric acid or abietic acid (industrial tall oil rosin), enhanced the proliferation of human keratinocytes in vitroand inhibited the expression of TNF-α, and to a lesser extent the expression of IL-1β in peripheral blood mononuclear cells. In this study, novel aqueous dispersions of spruce resin were used to investigate the effects of main resin components on keratinocyte proliferation and on the expression of key proinflammatory cytokines known to be associated with chronic wounds. The observations suggest that lignans, such as PINO, but not resin acids, are the components of resins that mediate the proliferative and TNF-α-suppressing effects. Lignans including PINO were identified as novel potential compounds in the treatment of chronic skin ulcers.

Material and Sensory Experiences of Mesolithic Resinous Substances

Mesolithic resinous adhesives are well known for their role as hafting mastic within composite technologies, yet it is increasingly clear that their usage was more diverse than this. Birch-bark tar has been recovered from Mesolithic contexts as chewed lumps linked to medicinal treatment of toothache and oral diseases, and as a decorative element on ornaments and art objects; and an amorphous resinous substance possibly derived from pine or spruce resin has been found within a burial context. This diversity of applications suggests that resins and tars may have been understood in different ways which did not always privilege their mechanical functionality. To underscore the limited archaeological perspective of conifer resins and tars as hafting agents, we draw on data sourced from a wide range of ethnographically documented societies, demonstrating the array of economic and social functions these materials have for contemporary hunter-gatherer groups. Using archaeological case studies, we illustrate how a deeper understanding of the material and sensory properties of resins and tars, and the trees from which they are derived, opens new insights into the diverse roles resinous materials performed within Mesolithic worldviews.

Control of foot-and-mouth disease in a closed society: A case study of Soviet Estonia.

Foot-and-mouth disease (FMD) is a dangerous infectious disease of even-toed ungulates, however since 1991, the European Union has banned preventive vaccination. During the occupation of the USSR, there were two outbreaks in Estonia: the first started in 1952 (at which time the barns typically housed about 20 cows); and the second began in 1982 (a period when barns typically housed several 100 animals). Neither outbreak was reported to the international community. At that time, it was also forbidden to talk about the disease in the internal media, and speakers could be punished. This study sought to find answers as to how the disease was treated and eliminated in the Estonian SSR, how infected animals and milk were handled, and if some of the methods used can be applied today. Written archival sources and 29 interviews with specialists remembering the outbreaks were used. Preventive slaughter of animals in the USSR was prohibited during the outbreak. As a preventive measure vaccination was used, traveling out of their counties by people were restricted and disinfection mats were used on the roads. In sick animals, udder wounds were treated with various wound ointments, such as zinc ointment, but also ointment made from boiled spruce resin. Birch tar was also recommended in the literature for leg treatments. Mouth wounds were washed with potassium permanganate solution. Workers used rubber gloves when handling sick animals. The barns were disinfected with lime and ash water. The milk from the diseased cows was pasteurized and given to calves, pigs, or diseased animals. Animals that did not recover were transferred to a meat processing plant. The meat was kept in potassium permanganate solution before processing and canned or made into sausages. When the disease was discovered, farm workers were locked in barns and released only when the disease had been eliminated. Such inhumane treatment could only be practiced in a totalitarian society.

Efficacy of Norway Spruce Ointments and Bacterial and Fungal Alterations in the Treatment of Castration Wounds in Piglets.

This study aimed to evaluate the efficacy of Norway spruce ointments on wound healing of castration wounds in piglets. This study included 95 male pigs randomly divided into five treatment groups: Norway spruce balm (Vulpuran), Norway spruce resin (Abilar), pork lard (ointment base of Vulpuran), no treatment (negative control) and antibiotic blue spray (Cyclo spray, positive control). Wound healing parameters (such as healing time, wound size, reddening of wound edges and surrounding, swelling, secretion and wound contamination), microbiological status and the haptoglobin level as an inflammation parameter were investigated. In the Norway spruce groups, some positive effects on wound healing parameters were found. In the first 6 days of treatment, Abilar or Vulpuran showed the smallest means of wound areas, and at the end of the study (day 15 + 17), the highest rates of completely closed wounds compared to the other groups. Vulpuran treatment led to significantly lower wound secretion (p = 0.003) and wound contamination (p = 0.015) than the untreated control did. Furthermore, the microbiological status was determined using MALDI-TOF-MS and partial 16S rRNA gene sequencing at different days of treatment. A comparison of the five treatment groups on day 3 revealed that Norway spruce led to the lowest rate of wounds colonised with fungi, mainly classified into genus Candida, (Abilar 77%, Vulpuran 70%) in comparison with blue spray (89%), lard (100%) and untreated control (100%). Fungi could only be detected in one of the 13 samples treated with Vulpuran on day 8, which nearly reached significance (p = 0.055).

Novel aqueous oil-in-water emulsions containing extracts of natural coniferous resins are strongly antimicrobial against enterobacteria, staphylococci and yeasts, as well as on bacterial biofilms.

The aim of this study was to examine the antimicrobial properties of novel aqueous natural rapeseed oil/saline emulsions containing different soluble components of spruce resin. The composition of aqueous resin emulsions was analysed by GC-MS and their antimicrobial properties were studied with challenge tests and with turbidometric assays. The emulsions were strongly antimicrobial against common Gram-positive and Gram-negative bacteria (including MRSA) as well as common yeasts. Furthermore, they inhibited the biofilm formation and eradicated the microbial biofilms on tested microbes. Characteristic for the emulsions was the presence of oxidized resin acids. Other main components present in emulsions, such as lignans and coumaric acids, were not antimicrobial, when tested separately. The results indicated that the oxidized resin acids were the antimicrobial components in the emulsions. Also, there appears to be a stoichiometric relationship between the number of resin acid molecules and the number microbe cells in the antimicrobial action. The fact that these solutions do not contain abietic acid, which is the main allergenic compound in resins, suggests that these solutions would be suitable, well-tolerated antimicrobials for various medical applications. The aqueous formulation will also allow the expansion of the use of these emulsions in from medical applications to the food preservatives and disinfectants.

Plant species reported from Swiss farmers to treat bovine respiratory diseases

Bovine respiratory disease (BRD) causes high morbidity in cattle, and extensive antibiotic treatment is leading to increasing resistance of BRD pathogens. Medicinal plants (MP) used traditionally by Swiss farmers for BRD might be a potential future therapeutic option. Since 2011 ethnoveterinary surveys have been conducted in Switzerland, with some 200 interviews leading to more than 1'500 use reports (UR). From this dataset all URs referring to BRD were extracted and analyzed with respect to plant parts used, preparation of remedies, administration, and oral daily dose (ODD). A total of 54 URs were documented (Table 1). The most common of the 15 reported MPs were Thymus vulgaris L. (TA), Picea abies L. (PA) and Ilex aquifolium L. (IA) representing some 70% of all URs. Common ways of administration of MPs were by direct feeding of the herb, as herbal teas, by inhalation, and as a liniment. For 25 of the 32 oral applications an ODD could be determined. ODDs reported for TA varied widely, but were comparable (median 0.19 g/kg0,75) to commonly used human ODDs of 0.13 – 0.26 g/kg0,75. The use of this plant was reasonable considering known antimicrobial, anti-inflammatory and spasmolytic properties. PA was administered by feeding of fresh twigs, but no detailed information on dosage could be obtained. However, antibacterial properties of spruce resin has been reported in literature. IA is commonly considered as toxic, but five UR corresponded to an average ODD of 0.41 g/kg0,75. Whether this ethnoveterinary use can be rationalized by the content in triterpene saponins is not clear at the moment. More research is needed, and the use of IA cannot be recommended at present. The 54 URs for BRD represent less than 5% of total URs documented so far from Swiss farms. In contrast to dermatological and gastrointestinal diseases the treatment of BRD with MPs seems less common. Nevertheless, several of the 15 documented MPs are interesting starting points for further investigations.

Efficacy of topical resin lacquer, amorolfine and oral terbinafine for treating toenail onychomycosis: a prospective, randomized, controlled, investigator-blinded, parallel-group clinical trial.

Norway spruce (Picea abies) produces resin to protect against decomposition by microbial pathogens. In vitro tests have shown that spruce resin has antifungal properties against dermatophytes known to cause nearly 90% of onychomycosis in humans. To confirm previous in vivo observations that a topical resin lacquer provides mycological and clinical efficacy, and to compare this lacquer with topical amorolfine hydrochloride lacquer and systemic terbinafine for treating dermatophyte toenail onychomycosis. In this prospective, randomized, controlled, investigator-blinded study, 73 patients with onychomycosis were randomized to receive topical 30% resin lacquer once daily for 9 months, topical 5% amorolfine lacquer once weekly for 9 months, or 250 mg oral terbinafine once daily for 3 months. The primary outcome measure was complete mycological cure at 10 months. Secondary outcomes were clinical efficacy, cost-effectiveness and patient compliance. At 10 months, complete mycological cure rates with the resin, amorolfine and terbinafine treatments were 13% [95% confidence interval (CI) 0-28], 8% (95% CI 0-19) and 56% (95% CI 35-77), respectively (P ≤ 0·002). At 10 months, clinical responses were complete in four patients (16%) treated with terbinafine, and partial in seven (30%), seven (28%) and nine (36%) patients treated with resin, amorolfine and terbinafine, respectively (P < 0·05). Resin, amorolfine and terbinafine treatments cost €41·6, €56·3 and €52·1, respectively, per patient (P < 0·001). Topical 30% resin lacquer and topical 5% amorolfine lacquer provided similar efficacy for treating dermatophyte toenail onychomycosis. However, orally administered terbinafine was significantly more effective in terms of mycological cure and clinical outcome than either topical therapy at the 10-month follow-up.

Ancient projectile weapons from ice patches in northwestern Canada: identification of resin and compound resin-ochre hafting adhesives

This article describes a study of adhesive residues on 16 projectile weapons, 15 from ice patches in southwest Yukon and one from the Selwyn Mountains, Northwest Territories. The objects selected for analysis cover much of the Holocene, with radiocarbon dates from 8103 to 170 cal. yr. BP and represent both throwing-dart and bow-and-arrow technology. The goal of the study was to identify the residues associated with hafting and to determine if patterns of material use exist. The residues were analyzed using a combination of analytical techniques: Fourier transform infrared spectroscopy (FTIR), gas chromatography–mass spectrometry (GC–MS), Raman spectroscopy, scanning electron microscopy–energy dispersive spectrometry (SEM–EDS) and polarized light microscopy (PLM). Hafting adhesive residues were found on nine objects that relate to throwing-dart technology and on two objects related to bow-and-arrow technology. In all cases where adhesive was found, the projectiles included chipped stone components. All adhesives, regardless of age, were found to be conifer resin, more specifically identified as spruce (Picea sp.). While the majority of adhesives were relatively pure, homogeneous spruce resin, in the case of three stone dart points, the spruce resin was intentionally mixed with red ochre to produce a compound adhesive. A fourth stone dart point showed the use of spruce “callus” resin, a type of resin produced during wound closure on the surface of the tree, which has a unique chemical signature.

Natural coniferous resin lacquer in treatment of toenail onychomycosis: an observational study

In in vitro tests, natural coniferous resin from the Norway spruce (Picea abies) is strongly antifungal. In this observational study, we tested the clinical effectiveness of a lacquer composed of spruce resin for topical treatment of onychomycosis. Thirty-seven patients with clinical diagnosis of onychomycosis were enrolled into the study. All patients used topical resin lacquer treatment daily for 9 months. A mycological culture and potassium hydroxide (KOH) stain were done from nail samples in the beginning and in the end of the study. Treatment was considered effective, if a mycological culture was negative and there was an apparent clinical cure. At study entry, 20 patients (20/37; 54%; 95% CI: 38–70) had a positive mycological culture and/or positive KOH stain for dermatophytes. At study end, the result of 13 patients was negative (13/19; 68%; 95% CI: 48–89). In one case (1/14; 7%; 95% CI: 0–21) the mycological culture was initially negative, but it turned positive during the study period. By 14 compliant patients (14/32; 44%; 95% CI: 27–61), resin lacquer treatment was considered clinically effective: complete healing took place in three cases (9%) and partial healing in 11 cases (85%). The results indicate some evidence of clinical efficacy of the natural coniferous resin used for topical treatment of onychomycosis.

Natural coniferous resin salve used to treat complicated surgical wounds: pilot clinical trial on healing and costs

Resin is a natural product of coniferous trees. Salves manufactured from spruce resin (Picea abies) have been used for centuries to treat wounds and skin infections. We report a pilot clinical trial designed to investigate healing rates, factors that contribute to delayed wound healing, cost-effectiveness, and incidence of allergic reactions when resin salve is used to treat complicated surgical wounds. The trial involved 23 patients in whom wound healing after surgery was delayed. These patients were assigned to resin salve treatment. The primary outcome measure was the number of days to complete wound healing. Secondary objectives included an assessment of factors contributing to delayed wound healing, an estimation of associated costs, and an investigation into the occurrence of allergic reactions related to resin salve therapy. The study achieved a healing rate of 100%. The mean ± SD healing time was 43 ± 24 days. The mean ± SD wound size (length × width × depth) was (29 ± 19) × (12 ± 7) × (4 ± 3) mm. Wound size, use of corticosteroids or other immunosuppressants, and immobilization were statistically significant (P < 0.05) contributors to delayed wound healing and impaired re-epithelialization. The total mean ± SD costs of the resin salve treatment were €45.0 ± 26.0 per patient during the entire treatment period and €1.2 ± 0.5 per treatment day. The rate of allergic reactions was 0%. The results of this pilot trial indicate that complicated surgical wounds may be treated successfully with resin salve. The treatment method is clinically effective and cost-effective, and the rate of allergic reactions is low.

Effects of Norway Spruce (Picea abies) Resin on Cell Wall and Cell Membrane of Staphylococcus aureus

Resin salve prepared from Norway spruce (Picea abies) has been used for centuries in traditional medicine to treat skin diseases. The authors studied with transmission and scanning electron microscopy, and with electron physiology, changes in cell wall and cell membrane of Staphylococcus aureus after exposure of the bacterial cultures to resin. After exposure, cell wall thickening, cell aggregation, changed branching of fatty acids, and dissipation of membrane potential of the bacterial cells were observed. The authors conclude that spruce resin affects the cell viability via changes in the cell wall and membrane, and impairs, thereby, the synthesis of energy in the bacteria.

Response of C and N transformations in birch soil to coniferous resin volatiles

The purpose of this study was to examine the effects of the resin volatile compounds of two coniferous tree species, Scots pine ( Pinus sylvestris L.) and Norway spruce ( Picea abies (L.) Karst.) on C and N transformations in soil under silver birch ( Betula pendula L.). Humus layers from two study sites were used, referred here as a N-poor soil (C:N ratio 30) and a N-rich soil (C:N ratio 19.5). In addition to these, N-poor soil added with arginine was used to ensure that the soil was not N-limited. Humus layers were subjected to resin treatments during a 28-day incubation period in the laboratory. The most abundant volatile compound in both resins was α-pinene; in spruce resin β-pinene was also abundant. Resins and pure α-pinene increased CO 2-C production, i.e. C mineralization, in both soils. In contrast, net N mineralization was clearly decreased in both soils, and net nitrification was completely stopped. There was no consistent effect on soil microbial biomass C or N. Based on these results, we conclude that volatile resin compounds affect C and N transformations in soil, but the mechanism behind these effects is still unclear.

The appearance of resin pockets in CT-images of Norway spruce ( Picea abies (L.) Karst.)

(L.) Karst.) was studied. The study also includes a comparison between measured and calculated CT-numbers of Norway spruce resin and wood. It was found that it should be possible to create algorithms that automatically detect large resin pockets in CT-images of Norway spruce. Compared to resin pockets in heartwood, resin pockets in green sapwood are more difficult to detect due to the high density of the surrounding wood. The study also showed that the correlation between measured and calculated CT-numbers was high and that it is possible to use the same function for conversion between CT-number and density for both green wood and resin.

Oxygen deficiency and spruce resin inhibition of growth of blue stain fungi associated with Ips typographus

The Eurasian spruce bark beetle, Ips typographus, carries spores of several fungi including Ophiostoma bicolor, O. penicillatum and O. polonicum. However, after attack on Norway spruce trees O. polonicum is the pioneer invader of the sapwood while other species follow. To determine the causes behind this distinct succession experiments were performed comparing growth rate, tolerance to oxygen-deficient conditions and to spruce resin between these early invaders. In sealed tubes with limited oxygen, O. polonicum grew for a longer time than three other species regularly associated with I. typographus in Norway. The non-volatile components of lesion resin induced by fungal attack, as opposed to preformed resin, inhibited the growth of all species, but particularly O. polonicum. O. polonicum grew rapidly on malt agar, but not faster than some of the other species associated with I. typographus. It is concluded that rapid growth and the ability to tolerate low oxygen pressure are important attributes for primary invaders, allowing tree resistance mechanisms to be overcome following mass inoculation.