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Abstract: Sydowia polyspora occurs often as an epiphyte or endophyte of conifers and is widely distributed around the world. It is also reported as a fungus associated with bark beetles. In this study, based on ITS sequence data and morphological characteristics, 14 strains collected from the beetle bodies and galleries of Tomicus minor and Tomicus yunnanensis infesting Pinus yunnanensis in Southwestern China were identified as S. polyspora. To assess the virulence of S. polyspora to P. yunnanensis, pathogenicity tests were conducted by inoculating the fungus in the stems and on needles of P. yunnanensis. The results after 30 days showed that the lesion lengths in the phloem after inoculation with S. polyspora were significantly longer than for the control. In addition, the fungus caused partly distinct chlorisis or discolouration of needles 14 days after inoculation. This suggests that S. polyspora is able to colonize stem phloem and pine needles of P. yunnanensis and thus may cause secondary damages to this host after being spread with bark beetles. [ABSTRACT FROM AUTHOR]

The antennal morphology and sensilla ultrastructure of Tomicus yunnanensis, T. minor, and T. brevipilosus were studied by scanning electron microscopy and transmission electron microscopy. Eight common sensilla types were recorded: (1) sensilla trichodea ( S.tr.) types 1 and 2 were located on the club and were innervated by five and eight dendrites, respectively; (2) sensilla chaetica ( S.ch.) types 1 and 2 had no dendrites in the sensilla lymph lumen; (3) sensilla basiconica ( S.b.), top-protuberated S.b. and fluted cones ( Fl.c.) occurred on the club; and Böhm bristles (B.b.) occurred on the funicle. S.b. were the most abundant and were innervated by 10-14 dendritic branches. Top-protuberated S.b., a new sensilla type, were innervated by one dendrite. Fl.c. were innervated by five dendrites. Only three sensilla furcatea were visible on the antennae of female T. yunnanensis. The possible functions of these sensilla are discussed in relation to their morphology and ultrastructure. No statistical differences between sexes were found in the size and numbers of each sensilla type. Although the three species had similar antennal morphology and sensilla type, sensilla on sub-segments 3 and 4 of the antennal club of T. minor were much sparser than those of T. yunnanensis or T. brevipilosus. Concerning the antennae of T. yunnanensis, there were more S.tr. type 2, S.ch. type 2 and S.b. and the size of S.tr. type 1 and S.b. were significantly greater than those of T. minor. Microsc. Res. Tech., 2012. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Various factors such as climate and resource availability influence the geographical distributions of organisms. Species sensitive to small temperature variations are known to experience rapid distribution shifts as a result of current global warming, sometimes leading to new threats to agriculture and forests. Tomicus piniperda and Tomicus destruens (Coleoptera, Curculionidae, Scolytinae) cause economic damage to pines in Europe and around the Mediterranean Basin. However, their respective potential distributions have not yet been studied at a large scale. The present study aimed to investigate the influence of climatic and host factors on the geographical distributions of both Tomicus species in Europe and around the Mediterranean Sea, and to establish maps of suitable areas., Using 114 published localities where the presence or absence of both species was unambiguously recorded, we gathered WorldClim meteorological records to correlate the occurrence of insects with bioclimatic variables and to build potential distribution maps., The two studied Tomicus species presented parapatric distributions and opposite climate demands, with T. destruens occurring in locations with warmer temperatures, whereas T. piniperda occurs under a colder climate. Amongst the investigated climate variables, temperature appeared to be most correlated with both species distributions., The potential ranges of both species were further restricted by the availability of pine hosts. It appeared that setting new pine plantations in regions where T. destruens or T. piniperda are still absent could favour a rapid expansion of their distributions. Our data will be useful when aiming to apply management strategies adapted to each species, and to forecast their potential range expansions/contractions as a result of climate warming. [ABSTRACT FROM AUTHOR]

In many bark beetles (Coleoptera: Curculionidae: Scolytinae), intraspecific competition is a limiting factor governing their population dynamics. The aim of this study was to evaluate the effect of increasing infestation densities on the breeding performance of Tomicus destruens (Wollaston), one of the main pests of Mediterranean pine forests. Six densities (ranging from 0.25 to 1.50 females dm−2) were tested under laboratory conditions on stone pine logs, assessing the mortality of eggs, larvae, and pupae, and recording the number of emerging adults. Density significantly affected the fertile tract of the maternal galleries, i.e., those containing eggs, which was shorter at densities higher than 0.75. Numbers of eggs, larvae, pupae, and adults per female decreased markedly when density increased from 0.25 to 1.5, although differences were statistically significant only at a density of 0.75 and higher. The lowest mortality was found in larvae reared at a density of 0.25 (17.7%) and the highest in pupae at 1.5 (84.8%). Increasing density affected the pre-emergence stages in different ways, with pupae and larvae suffering the highest increases in mortality (39.5 and 163.6%, respectively). The breeding performance of T. destruens (number of eggs laid reaching adulthood) progressively decreased from 17 to 4% with increasing densities, although at low infestation, the mean number of emerging adults per dm2 of bark increased with density, showing a positive trade-off between female fecundity and female density. In conclusion, breeding densities higher than 0.75 female dm−2 decreased female fecundity and elicited high mortality, mainly in larvae. [ABSTRACT FROM AUTHOR]

The article discusses the role of plants enemies in the forestry of indigenous pines compared to nonindigenous. The study examines the enemy release hypothesis in the productive forests of Galicia, Spain, where one of the most important pests of pines is the indigenous bark beetle. It also tested the prediction that Tomicus piniperda would reduce growth of the indigenous Pinus pinaster more than it did the nonindigenous Pinus radiata. The analysis was conducted using a landscape with a mosaic of alternative pine species and a gradient of Tomicus piniperda abundance.

The association between Tomicus piniperda L. (Col., Scolytinae) and fungi was studied in a Pinus sylvestris L. forest in Mielec-Mościska. Fungi were isolated from overwintered adult beetles taken from two stands situated in different distance from timber yard. Two media were used for isolation. The results showed great diversity of fungi associated with T. piniperda: 1895 cultures, representing 64 species, were isolated. Penicillia and Hormonema dematioides were the dominant species, found in 20.2% and 17.8% of all beetles, respectively. A frequently isolated ophiostomatoid fungi was Ophiostoma minus. Qualitative and quantitative differences in the mycobiota composition of this insect between two stands were detected. The highest richness and diversity of fungal species appeared in the samples taken from the location where the trees were heavily damaged by shoot-feeding of T. piniperda. Differences were most clear for the pathogenic O. minus, which was a common fungal associate of the insects in this stand. [ABSTRACT FROM AUTHOR]

The pine shoot beetle Tomicus destruens (Wollaston) (Coleoptera: Curculionidae: Scolytinae) is one of the main pests of Mediterranean forests, where it is oligophagous on Mediterranean pines. However, possible global warming may make the insect move to higher latitudes and altitudes, allowing it to attack new pine species. In this respect, the aim of the present article was to assess both the acceptance and performance of T. destruens offered host and non-host pine species. A no-choice breeding experiment was set up under laboratory conditions, using logs of three Mediterranean ( Pinus pinea L. , Pinus pinaster Miller, and Pinus halepensis Aiton) and two continental ( Pinus nigra Arnold and Pinus sylvestris L.) pine species. Log debarking at the end of adult emergence assessed parent fecundity, egg, and larval mortality. The quality of callow adults emerging from each tested pine was evaluated on the basis of their longevity on a semiartificial diet. Tomicus destruens colonised all tested pine species, but did not reproduce in Scots pine, taking about 79 days to complete development with no differences among pines tested. The best breeding performance, evaluated as female fecundity and adult production, was observed in P. halepensis, and the lowest in P. pinaster. On average, adults emerging from P. pinea survived longer (83 days) than from other pines, and adult longevity was the lowest in males emerging from P. nigra. Austrian pine, which under natural conditions is usually not a host of T. destruens, allowed insect development and adult production similar to P. pinea and P. pinaster. [ABSTRACT FROM AUTHOR]

Phylogeographic studies are often focused on temperate European species with relict footholds in the Mediterranean region. Past climatic oscillations usually induced range contractions and expansions from refugial areas located in southern Europe, and spatial distribution of genetic diversity show that northward expansions were usually pioneer-like. Actually, few studies have focused on circum-Mediterranean species, which probably were not influenced in the same way by climatic oscillations. We present the phylogeography of the bark beetle Tomicus destruens, which is restricted to the whole Mediterranean basin and the Atlantic coasts of North Africa and Portugal. We systematically sequenced 617 bp of the mitochondrial genes COI and COII for 42 populations ( N = 219). Analysis revealed 53 haplotypes geographically structured in two clades, namely eastern and western clades, that diverged during the Pleistocene. A contact zone was identified along the Adriatic coast of Italy. Interestingly, we found contrasting levels of genetic structure within each clade. The eastern group was characterized by a significant phylogeographic pattern and low levels of gene flow, whereas the western group barely showed a spatial structure in haplotype distribution. Moreover, the main pine hosts were different between groups, with the Aleppo-brutia complex in the east and the maritime pine in the west. Potential roles of host species, climatic parameters and geographical barriers are discussed and the phylogeographic patterns are compared to classical models of postglacial recolonization in Europe. [ABSTRACT FROM AUTHOR]

The association between Tomicus destruens and fungi of the genus Leptographium was studied in Pinus pinea and P. pinaster forests in Tuscany, central Italy. Fungi were isolated from adult beetles and from pine tissues from infested trees. On average, Leptographium spp. were associated with 18% of beetles in breeding galleries, 35% of emergent brood beetles and 18% of beetles undergoing maturation feeding in pine twigs. The fungal species most frequently identified were Leptographium wingfieldii and L. lundbergii while L. guttulatum and L. serpens were also found. [ABSTRACT FROM AUTHOR]

We explored how two recently introduced methods to promote biodiversity during the timber harvest in boreal forests – green tree retention and use of fire – may affect damages caused by pine shoot beetles ( Tomicus piniperda and Tomicus minor; Col., Scolytinae) in the surrounding pine forests. The experimental design included 24 separate study sites, 3–5 ha each, which were assigned to different treatments according to factorial design. Retention levels included 0, 10, 50 m3/ha and uncut controls. Twelve of the sites were burned and thus there were three replicates of each treatment combination. Old and new fallen pine shoots were counted from transects in adjacent pine-dominated forests 2 and 3 years after the treatments. Populations of Tomicus spp. in the sites were monitored using window traps before and after the treatments, and by examining felled sample trees. Numbers of fallen shoots returned to background levels around unburned and burned clearcuts with no retention trees in 3 years after the treatments, but remained still at increased level in burned harvested sites with 10 and 50 m3 of retained trees per hectare. Numbers of fallen shoots in burned uncut forests increased in one site only, where the fire was intense enough to kill large pine trees, but the damage did not extend outside the burned area. Shoot numbers remained at such low levels (<18 000 shoots/ha) in all treatment combinations that growth losses were not likely. Numbers of egg galleries of Tomicus spp. in trees killed by fire were low, indicating that burnings that take place after the swarming of Tomicus beetles create dead wood that is not optimal for the breeding of these pests. We conclude that green tree retention and prescribed use of fire do not automatically affect populations of Tomicus spp. more than traditional forestry operations (thinnings and clearcuttings) do. [ABSTRACT FROM AUTHOR]

Aim, location Tomicus (Coleoptera, Scolytidae) species are some of the principal pests of Eurasian forest and are represented by three coexisting species in Spain, Tomicus piniperda (Linnaeus, 1758), Tomicus destruens (Wollaston, 1865) and Tomicus minor (Harting, 1834). The distribution of two taxa are unknown as they have until recently been considered separate species. Therefore, we model the potential distribution centres and establish the potential distribution limits of Tomicus species in Iberia. We also assess the effectiveness of different models by comparing predicted results with observed data. These results will have application in forest pest management. Methods Molecular and morphological techniques were used to identify species from 254 specimens of 81 plots. For each plot, a Geographical Information System was used to extract a set of 14 environmental (one topographic, six climatic) and biotic variables (seven host tree distributions). General Additive Models and Ecological Niche Factor Analysis models are applied for modelling and predicting the potential distribution of the three especies of Tomicus. Results The results of both modelling methodologies are in agreement. Tomicus destruens is the predominant species in Spain, living in low and hot areas. Tomicus pin iperda occurs in lower frequency and prefers wet and cold areas of north-central Spain. We detected sympatric populations of T. destruens and T. piniperda in Northern coast of Spain, infesting mainly P. pinaster. Tomicus minor is the rarest species, and it occupies a fragmented distribution located in high and wet areas. The remarkable biotic variable is the distribution of P. sylvestris, incorporated into the models of T. destruens and T. piniperda. Main conclusions These results indicate that in wet areas of north-central Spain where T. piniperda occurs (and possibly the high altitudes of the southern mountains), T. destruens has a climatic distribution limit. In the northern border of this area, both species overlap their distributions and some co-occurrences were detected. Tomicus minor potentially occurs in high and wet fragmented areas. [ABSTRACT FROM AUTHOR]

Tomicus piniperdaandHylurgops palliatuscolonize susceptible host trees by responding to host-specific odour signals as well as by avoiding volatiles emanating from non-host conifers. In the field, the pine shoot beetle,T. piniperda, responded in high numbers to natural odour sources provided by their host tree,Pinus sylvestris, while the non-host conifersLarix decidua,Picea abies, orPseudotsuga menziesiiwere significantly less attractive. In contrast, the spruce bark beetle,Hylurgops palliatus, preferentially responded to its main host,P. abies. Furthermore,T. piniperdaattacks onP. sylvestrisbolts decreased in presence of bark and wood particles from the non-hostP. abies, whereas particles fromP. menziesiiappeared not to affectT. piniperdaattacks. Apparently, tree-specific volatiles act at close range as specific signals that lead to the successful discrimination and colonization of the respective host tree species. [ABSTRACT FROM AUTHOR]

The pine shoot beetle,Tomicus piniperda(L.) (Col., Scolytidae) is an exotic pest of pine,Pinusspp., in North America. It is attracted strongly to host volatiles (±)-α-pinene, (+)-3-carene, andα-terpinolene. Attraction to insect-produced compounds is less clear. Other potential attractants includetrans-verbenol, myrtenol, myrtenal, nonanal andα-pinene oxide. We conducted a series of field experiments to determine if any of these compounds would increase attraction ofT. piniperdatoα-pinene, either individually or in various combinations. None of the individual compounds increased attraction. Although several combinations that includedtrans-verbenol, nonanal, myrtenol, or myrtenal increased attraction, results were variable between experiments. [ABSTRACT FROM AUTHOR]

1 The pine shoot beetle, Tomicus piniperda (L.) (Coleoptera: Scolytidae), is an exotic pest of pine, Pinus spp., and was first discovered in North America in 1992. 2 Although primary attraction to host volatiles has been clearly demonstrated for T. piniperda, the existence and role of secondary attraction to insect-produced pheromones have been widely debated. 3 Currently, commercial lures for T. piniperda include only the host volatiles α-pinene in North America and α-pinene, terpinolene and (+)-3-carene in Europe. Several potential pheromone candidates have been identified for T. piniperda. 4 We tested various combinations of host volatiles and pheromone candidates in Michigan, U.S.A., and Ontario, Canada, to determine an optimal blend. 5 Attraction of T. piniperda was significantly increased when trans-verbenol (95% pure, 3.2% cis-verbenol content) was added with or without myrtenol to α-pinene or to blends of α-pinene and other kairomones and pheromone candidates. 6 Our results, together with other research demonstrating that trans-verbenol is produced by T. piniperda, support the designation of trans-verbenol as a pheromone for T. piniperda. A simple operational lure consisting of α-pinene and trans-verbenol is recommended for optimal attraction of T. piniperda. [ABSTRACT FROM AUTHOR]

Abstract 1 In South-western China, Yunnan pines Pinus yunnanensis , suffer considerable damage from an undescribed Tomicus sp. previously thought to be T. piniperda . 2 To assess the effect of shoot maturation feeding (during which an aggregation process appears to occur) on host resistance to attacks on the bole, the relationships between shoot damage, bole attack density and tree survival were studied. 3 Attack distribution in the crown and in the stem did not vary between killed and surviving trees, indicating that mortality is determined by the quantity of attacks. 4 The level of shoot damage and bole attack density were positively and linearly correlated. This can be explained by the fact that bole attacks are caused by beetles coming from the crown of the same tree. 5 A critical threshold of bole attack density (around 80 attacks/m2 ) above which trees die was observed. However, because attacks continue after this threshold is reached, the density of failed attacks on the killed trees was used as an estimator of the threshold density. It decreased when shoot damage increased. 6 The existence of a critical threshold of shoot damage (60% damaged shoots) was also demonstrated. Above this threshold, stem attack density was always sufficiently high to kill trees. 7 The results emphasize that concentration of shoot attacks is the main reason for the extensive tree damage observed in China. 8 A model of relationships between shoot and stem attacks is proposed, suggesting that management to reduce shoot attacks would protect trees from dying by both decreasing the number of bole attacks and raising the threshold for successful attack density on the bole to levels that could not be attained. [ABSTRACT FROM AUTHOR]

Abstract 1 After a 1-year, extensive pine looper (Bupalus piniaria ) outbreak, plots were laid out to study tree susceptibility to attack, and performance of Tomicus piniperda in pine trees suffering from varying levels of defoliation. 2 Tomicus piniperda was the dominating stem-attacking species among the primary stem colonizers, and 82% of all trees that died had been colonized by T. piniperda . 3 Beetle attacks primarily struck severely defoliated trees, i.e. trees that suffered from 90% to 100% defoliation. 4 Beetle attacks peaked in the second year after cessation of the outbreak, and suppressed trees were both more frequently attacked and more susceptible to beetle attack than intermediate and dominant trees. 5 Trees surviving beetle attacks carried more foliage than trees that did not survive the attacks. 6 A single year of severe defoliation is enough to render pine trees susceptible to secondary pests, such as T. piniperda . [ABSTRACT FROM AUTHOR]

The pine shoot beetle, Tomicus piniperda, is causing substantial tree mortality to Pinus yunnanensis in south-western China, whereas the same species in Europe seldom kills Pinus sylvestris. In order to understand this difference in aggressiveness, we studied the shoot feeding ecology of the pine shoot beetles in Yunnan, and compared it with European results. We found many similarities in the shoot feeding behaviour of T. piniperda, and also that of Tomicus mirror, which was common locally. In contrast to Europe, however, the pine shoot beetles in Yunnan seem to be able to predispose the host trees for stem attack by intensive shoot-feeding. It has also been observed that beetles aggregate in certain trees during shoot feeding, but we could not verify that in our experiment. [ABSTRACT FROM AUTHOR]

Abstract 1 Morphological characters were elaborated and part of the mitochondrial COI gene was sequenced in order to facilitate the determination of the three European pine bark beetles Tomicus piniperda, T. destruens and T. minor . The sequence information also provided the first information on the phylogenetic and phylogeographical relationships of these species. 2 Three hair rows were found on the antennal club of T. destruens between the second and third suture. Tomicus piniperda had only one row. Three different hair types were detected on the elytra – two hair types were found on T. piniperda , whereas the third hair type was only detected on the elytra of T. destruens . 3 The COI region (445 bp) revealed high sequence divergence among T. destruens , T. piniperda and T. minor . The three species proved to be monophyletic species with 16.98–19.23% sequence divergence. A phylogenetic approach placed T. minor and T. destruens as sister taxa, which contradicts the morphological findings. 4 European populations of T. piniperda shared two haplotypes, indicating a homogenous distribution of the genotypes. In the American populations only one of these European haplotypes was found. The Greek, Italian and Spanish T. destruens populations revealed three population-specific haplotypes, indicating restricted gene flow. 5 Species-specific primers were designed to allow a rapid and definitive determination of the two sibling Tomicus species by PCR. [ABSTRACT FROM AUTHOR]

Abstract Genetic diversity and population structure of Tomicus piniperda was assessed using mitochondrial sequences on 16 populations sampled on 6 pine species in France. Amplifications of Internal transcribed space 1 (ITS1) were also performed. Our goals were to determine the taxonomic status of the Mediterranean ecotype T. piniperda destruens , and to test for host plant or geographical isolation effect on population genetic structure. We showed that T. piniperda clusters in two mtDNA haplotypic groups. Clade A corresponds to insects sampled in continental France on Pinus sylvestris , P. pinaster and P. uncinata , whereas clade B gathers the individuals sampled in Corsica on P. pinaster and P. radiata and in continental France on P. pinea and P. halepensis . Insects belonging to clade A and clade B also consistently differ in the length of ITS1. Individuals belonging to both clades were found once in sympatry on P. pinaster . Genetic distances between clades are similar to those measured between distinct species of Tomicus . We concluded that clade B actually corresponds to the destruens ecotype and forms a good species, T. destruens . Analyses of molecular variance (amova) were conducted separately on T. destruens and T. piniperda to test for an effect of either geographical isolation or host species. Interestingly, the effect of host plant was significant for T. piniperda only, while the effect of geographical isolation was not. Pine species therefore seems to act as a significant barrier to gene flow, even if host race formation is not observed. These results still need to be confirmed by nuclear markers. [ABSTRACT FROM AUTHOR]

Abstract The bark beetles species Tomicus destruens and T. piniperda constitute one of the main pests of European and Asian forests. T. destruens has been thought to be the same species as T. piniperda by some authors. A rapid PCR-based method using internal transcribed spacers (ITS1 and ITS2) of the ribosomal DNA has been developed in order to identifying these two species. We have studied differences in the size of the ITS1, and differences in the sequence and restriction patterns of the ITS2 in 75 individuals of both species. The results indicate a size difference of about 100 bp in the ITS1 of T. destruens and T. piniperda . The size of the ITS2 spacer is similar in both species (≈ 600 bp). However, the sequence is consistently different between T. destruens and T. piniperda in all populations analysed, showing some characteristic indels. Differences in the restriction target in both species for the enzymes Hin cII and Dra I produce different band patterns in agarose NuSieve 5% gel electrophoresis. These data suggest the validity of T. destruens as a phylogenetically differentiated entity from T. piniperda . The phylogenetic analysis of a 789 bp fragment of the 3′ end of the cytochrome oxidase I gene (COI) agrees with the two groupings obtained with the ITS2, showing a phylogenetic clustering rather than a phylogeographic structure. [ABSTRACT FROM AUTHOR]

The pine shoot beetles Tomicus minor and T. piniperda are common in the Nordic countries. Of these, T. piniperda may attack and kill living but severely stressed trees, whereas T. minor has never been reported to be individually responsible for killing live trees. Both species are associated with blue-stain fungi: T. minor with Ophiostoma canum and T. piniperda with Leptographium wingfieldii and Ophiostoma minus. The growth of these fungi was studied in phloem and sapwood of live Scots pine trees, on malt agar, and on malt agar under oxygen-deficient conditions. Leptographium wingfieldii was more virulent (i.e. caused more extensive host symptoms) grew more quickly on malt agar, and was less affected by oxygen-deficient growth conditions than either O. minus or O. canum. Ophiostoma canum was least virulent. In low-density inoculations it induced lesions similar to those induced by sterile control inoculations; it grew very slowly on malt agar and stopped growing after ≈30 mm under oxygen-deficient conditions. Ophiostoma minus was intermediate in all respects. The different virulence of the blue-stain fungi associated with the two pine shoot beetles may explain the lower level of aggressiveness in T. minor. [ABSTRACT FROM AUTHOR]

We tested the hypothesis that green leaf volatiles (GLVs) disrupt the response of overwintered pine shoot beetles, Tomicus piniperda (L.) to multiple-funnel traps baited with the attractive host volatile α-pinene. A combination of four GLV alcohols, 1-hexanol (E)-2-hexen-1-ol (Z)-2-hexen-1-ol, and (Z)-3-hexen-1-ol, caused 54 and 36% reduction in the number of pine shoot beetles captured in two separate trapping experiments. Similarly, a combination of the four alcohols plus two GLV aldehydes, hexanal and (E)-2-hexenal, caused 38% reduction in the number of pine shoot beetles captured compared with α-pinene alone. A blend of the two GLV aldehydes was not disruptive. None of the four GLV alcohols nor the two GLV aldehydes were disruptive when tested individually. The finding that the blend of four GLV alcohols reduced attraction of T. piniperda supports the general hypothesis that GLVs common to nonhost angiosperms are disruptive to conifer-attacking bark beetles (Scolytidae). [ABSTRACT FROM AUTHOR]

This study investigated the impacts of Tomicus minor on Tomicus piniperda when the two Tomicus species coexist in the trunks of living Yunnan pine (Pinus yunnanensis L.) trees growing in the Kunming region, in south-western China. Tomicus piniperda mostly locates in the mid- and upper trunks of Yunnan pine tree; whereas T. minor mainly attacks the mid- and lower trunks. In the mid-trunk area from 1.0 to 5.0 m above ground, there are overlapping attack zones for the two Tomicus species, which accounts for an average of 80% of the entire zone occupied by T. piniperda and an average of 70% of the zone occupied by T. minor. In correspondence with their attack distributions, the average attack densities of the two species varied with height along the trunk, with 165.3 egg galleries per m[sup 2] at a height of 6 m for T. piniperda, and 138.2 egg galleries per m[sup 2] at the 1 m height for T. minor. It is suggested that T. minor adjusts its attack pattern with respect to T. piniperda, and thereby minimizes interspecific competition. No remarkable difference of average T. piniperda egg gallery length was found between the zone in which only T. piniperda occurred and the zone in which T. piniperda and T. minor coexisted; this is suggested to be due to low host quality in the upper trunk region where only T. piniperda was present. The number of T. piniperda larval galleries was highest when only T. piniperda was present, and decreased as T. piniperda and T. minor coexisted, particularly in the case when the density of T. piniperda was less than that of T. minor. Average larval density was 1649 larval galleries per m[sup 2] where only T. piniperda occurred. However, when T. piniperda coexisted with T. minor, T. piniperda larval density averaged 1010 per m[sup 2] when T. piniperda density was higher than T. minor, and averaged 442 per m[sup 2] when T. piniperda density was less than T. minor, which led to the conclusion that T. minor makes a negative impact on T. pin... [ABSTRACT FROM AUTHOR]

This article focuses on effects of pruning young Scots pines on host vigour and susceptibility to two blue-stain fungi Leptographium wingfieldii and Ophiostoma minus associated with pine shoot beetle Tomicus piniperda. Tomicus piniperda were inoculated into 25-year old Scots pines. Both fungi invaded the inner bark and the sapwood at the points of inoculation. Leptographium wingfieldii caused larger lesions in the bark but Ophiostoma minus tended to grow faster in the sapwood. The lesion formation and the content of resin acids in lesion did not differ between fungi.

Examines the effects on growth of simulated and induced shoot pruning by Tomicus piniperda as related to carbohydrate and nitrogen dynamics in Scots pine. Small and transient effect on stem growth of even severe prunings; Improvement in nitrogen status and an increased photosynthetic capacity of remaining and new needles.

Tomicus piniperda is the first bark beetle to swarm in the spring in Fennoscandia. The intensity of swarming is directly related to air temperature above a certain threshold and reaches 100% asymptotically. While temperature sums above the threshold accumulate, swarming rate slows down. A non-linear model was built on these considerations. The model was calibrated to window trap material from northern Finland, and it was validated against published material mainly from Norway. The threshold temperatures in these materials were 10.8°C and 11.6°C. respectively. The predictions of the model were satisfactory, and the model will be tried as a part of an entire population dynamics model. The possibilities to predict not only timing, but also the frequency of attack are discussed. [ABSTRACT FROM AUTHOR]

Tomicus piniperda is a bark beetle that causes damage to various pine species across a wide geographical range. We developed five microsatellite polymorphic markers using an enrichment protocol. All loci could be successfully amplified with no evidence of null alleles and will be useful for population genetic studies. Cross-species amplifications show that at least some of the markers could be useful in four other Tomicus species. [ABSTRACT FROM AUTHOR]

During 1991, 1992, &, 1993 a study on shoot feeding, overwintering and the presence of Tomicus minor inside pine shoots was carried out in the province of León (NW Spain). This paper deals with the duration of these processes, overwintering sites and pine shoot feeding characteristics: age, diameter, length, occurrence of exit holes, multiple attacks and length of the burrowed tunnels. It also refers to the degree of shoot occupation, sex-ratio and detected adult mortality. [ABSTRACT FROM AUTHOR]