Xyleborus Dispar Research Articles

USE OF DEAD OAK WOOD IN FURNITURE PRODUCTS

Today, furniture made of wood, on which the openings of insect passageways are visible, is popular. Artificially creating such holes on healthy wood does not meet the aesthetic needs of consumers. Considering the annual increase of 8-10 thousand hectares in drying oak stands in Ukraine and, accordingly, the cost of deadwood reduced by almost 50%, it is proposed to use it after proper treatment to destroy pests for the manufacture of furniture products. An analysis of wood disinfection methods was carried out, which transformed over time from non-toxic substances and processing methods – oil, tar, resin, storage in salt water, charring to modern ones using harmful chemical compounds – pentachlorophenol, alkaline chloride, sodium fluorosilicates, tars, DDT, etc. Analysis of available methods for exterminating timber pests allowed distinguishing antiseptics, fumigation, ultra-high frequency current treatment and thermal modification. The purpose of this study was to determine the method of disinfection of sawn goods made from deadwood oak for further use in furniture products. Theoretical and experimental methods were used to achieve this purpose. The scientific originality of this study lies in the application of the fuzzy logic method to select the priority method of wood disinfection, which lies in decomposition of the problem into simpler components and step-by-step prioritisation of the evaluated components using paired comparisons. For alternative options to achieve the purpose, the following criteria were applied: efficiency, environmental friendliness, industrial manufacturability, durability of the result. The corresponding calculations performed, confirmed by the required consistency index, showed the priority of the method of thermal modification of wood. Experimental studies of heat treatment with the proposed modes of deadwood oak with existing pests, namely Xyleborus dispar (Xyleborus dispar), were carried out. The study determined the possibility of using the action of hot temperatures (t>110 °C) for complete sterilisation of deadwood oak. The result of practical application of this eco-safe method for the manufacture of tabletops has shown its effectiveness and can be useful for furniture makers

Biological features and phenology of the odd bark beetle development (Xyleborus dispar F.) on the territory of Transcarpathia

On the basis of literature analysis and primary research biological features of such pest as an odd bark beetle Xyleborus dispar F are described and the phenology of its development is established. This polyphag is known to harm both forest plantations and fruit cultures. The main species damaged by bark beetles include both coniferous and deciduous and fruit trees (apple, pear, plum, bird cherry, rowan). Significant damage is caused by apple orchards of intensive type which due to planting density and softness of wood are vulnerable to damage by phytophagous. The main difficulty in the fight against bark beetle is associated with a hidden way of life and the passage of almost all stages of development inside the tree. One of the main signs of bark beetle development in Transcarpathia is early flight. Already in early April, there are signs of penetration of bark into the tree - the appearance of smut on the bark and wood chips in the trunk strip. Another danger is the high level of fertility of bark beetles, which threatens the rapid spread of the adult pest, which in turn leads to significant economic losses for intensive orchards and causes irreparable damage to apple orchards. Since the odd-numbered western bark beetle is a relatively new pest for apple orchards in Transcarpathia, the preparation and calculation of the appearance and passage of the main phases of development is a thorough step in the fight against this polyphagous. Intensive apple orchards which are particularly vulnerable to phytophagous damage due to planting density and soft wood significantly suffer from the pest. Based on a three-year monitoring process a phenogram of bark beetle development in the lowland part of Transcarpathia was developed, and the approximate values of effective temperatures required for the passage through different phases of the pest were calculated. It was established that during the growing season in the study area the odd western bark beetle develops in one generation. However, the summer generation of adults which develop in trunks of apple trees emerges in mid-July and repopulates new trees for final wintering. This creates an additional need for measures to protect apple trees from pests. The results of the research allow gardeners to adjust the integrated system of orchard protection, as well as to include additional pest detection measures in the program of effective apple growing.

Vectors of Dutch Elm Disease in Northern Europe.

Simple SummaryDutch elm disease (DED) has been killing elms for more than a century in northern Europe; the trees’ health status has worsened substantially in recent decades. Elm bark beetles Scolytus spp. are vectors of DED. Our aim was to estimate the distribution range of elm bark beetles and to detect potential new vectors of DED agents in northern Europe. Beetles were caught with bottle traps and manually. Then DNA from each specimen was extracted and analysed by the third generation sequencing method. DED agents were detected on the following bark beetles for Europe: Scolytus scolytus, S. triarmatus, S. multistriatus, S. laevis, and on new vectors: Xyleborus dispar and Xyleborinus saxesenii. The spread of Scolytus triarmatus, S. multistriatus and Xyleborinus saxesenii has been remarkable for the last two decades, and S. triarmatus and X. saxesenii are relatively recent newcomers in the northern Baltics. The problem is that the more vectoring beetles there are, the faster spread of Dutch elm disease from tree to tree.Potential Dutch elm disease vector beetle species were caught with pheromone bottle traps and handpicked in 2019: in total, seven species and 261 specimens were collected. The most common was Scolytus triarmatus, but by percent, the incidence of Ophiostoma novo-ulmi was highest in Scolytus scolytus, followed by Xyleborinus saxesenii and S. triarmatus. We analysed the beetles’ DNA using PacBio sequencing to determine vector beetles of Ophiostoma novo-ulmi. Ophiostoma novo-ulmi was found on six out of seven analysed beetle species: Scolytus scolytus, S. triarmatus, S. multistriatus, S. laevis, Xyleborinus saxesenii and Xyleborus dispar. The last two beetles were detected as vectors for Ophiostoma novo-ulmi for the first time. Previous knowledge on the spread of beetles is discussed.

Захист інтенсивних яблуневих садів від комплексу фітофагів у степовій зоні України

According to long-term surveys of apple plantations in Ukraine, they are da maged by an unpaired western bark beetle (Xyleborus dispar F.). The share of this pest colonizing perennial plantations in Ukraine is about 30%, and there is also a tendency of spreading colonization of this type of production tracts over fruit plantations. The prevalence of bark beetle in production areas of orchards has increased significantly in recent years. Unpaired pest, unlike many other species of bark beetles, completely destroys healthy trees. The increase in the number and harmfulness of odd western bark beetle is associated with climate change, the use of various protection systems, etc. Nowadays measures to reduce the number of this species consisted only of a mechanical technique (cutting and burning dam-aged trees) and spraying of garden plantings in the phase of “swelling of the buds ‒ beginning of budding” with old insecticides of second generation (metaphos, chlorophos, carbophos, etc). Pruning and burning damaged trees are an ineffective measures to reduce the number of pests in orchards. The expediency of testing a number of modern insecticides is urgent and effective against a complex of phytophages in the “green cone” phase ‒ “ Rose bud” (beetle, goose, budworm, apple blossom beetle, aphids, leafworms) ‒ “end of flowering” (leafworms, aphids) and can be effective against the western unpaired bark beetle. The basis was the du-ration of action and the peculiarities of the mechanism of action of these insecticides (contact intestinal action ‒ Aktara 240 SC, HP, Mospilan, P. P., Calypso 480 SC , etc. and contact, par-tially systemic action with fumigation effect ‒ Bi‑58 new, etc., Pirinex Super, etc., Danadim stable, etc., Danadim Mix, etc., Fufanon 570, etc.). The use of the drugs mentioned above (for double treatment of plantings) demonstrated high technical efficiency against openly living phytophages (for the first treatment of plantations ‒ against aphids, leafworms, garden wee-vils and tube worms, for the second treatment ‒ against aphids, leafworms), which amounted to 91,3‒99,2%. The western unpaired bark beetle (Xyleborus dispar F.) is a permanent species in the industrial areas of the apple tree. And therefore, protecting trees from it in industrial plantings should be an integral part of modern technology for obtaining fruit products. Un-doubtedly, the application of the complex of insecticides Bi‑58 new, к.е. (2,0 l/ha), Pirinex Super, к.е. (1,25 l/ha), Danadim stable, etc. (2,0 l/ha), Danadim Mix, etc. (2,0 l/ha), Fufanon 570, E.C. (2,0 l/ha) is a highly effective method for reducing the harmfulness of the western unpaired bark beetle in industrial plantations of apple trees, an economically beneficial meth-od in the modern intensive protection technologies.

Bioecological peculiarities and economic significance of large fruit bark beetle (Scolytus mali Bechstein, 1805) and fig bark beetle (Hypoborus ficus Erichson, 1836) in the southern slopes of the Great Caucasus (Azerbaijan)

Background. Bark beetles (Coleoptera, Curculionidae, Scolytinae) are major pests of wood-fruit trees, and infestations often accelerate tree death. Bark beetles are insects that are closely related to their host trees. According to the type of feeding they belong to xylophages [7]. They prefer weakened, sick or damaged trees. Thus, bark beeteles can more easily penetrate into trees affected by various natural phenomena (wind, storm, rain) or primary pests. They are hardly ever found in rotting trees. The research was carried out on the southern slopes of the Great Caucasus during the period 2013–2016. The great difference in the altitude in the study area results in a variety of natural conditions. This, in turn, leads to the richess of fauna and flora of the area. Thus, valuable fruit trees grow both in the forests and fruit farms of the study region. However, large numbers of fruit trees are attacked by bark beetles every year, which negatively affects the numbers and the quality of trees. Untimely processing of the trees leads to their drying and destruction. According to modern systematics, bark beetles belong to the Scolytinae (Latreille, 1804) subfamily of the Curculionidae (Latreille, 1802) family. There are about 6,000 species of bark beetles from 28 triba and 230 genera in the world [8]. These insects also cause serious damage in countries neighboring of Azerbaijan [1, 2, 9, 11 ]. Despite the fact that bark beetles are of great agricultural importance, they are not sufficiently studied in Azerbaijan. Materials and Methods.The material for research was collected and treated according to common entomological methods. The vegetative organs of various trees were cut and dissected to detect adult beetles, eggs and larvae of bark beetles. Identification of bark beetles was carried out according to keys. MBS-9 microscope was used to determine the morphological features of beetles. Results. As a results of the research, we analyzed 241 samples (237 adults and 4 pupae) of bark beetles collected in 7 districts of the southern slopes of the Greater Caucasus, of which 54 specimens belonged to Scolytus mali and 187 to Hypoborus ficus. Conclusion. Out of 30 species of bark beetles detected on the southern slopes of the Greater Caucasus, 7 ones (Scolytus mali Bechst., S. amygdali Guer., S. fasciatus Rtt., S. rugulosus Ratz., Hypoborus ficus Er., Xyleborus dispar F., X. saxeseni Ratz.) were determined as fruit trees pests. Two of them (Scolytus mali and Hypoborus ficus) are widely distributed in the area and cause serious damage to fruit trees.

КОМАХИ-КСИЛОФАГИ ЛИСТЯНИХ ПОРІД У НАЦІОНАЛЬНОМУ ПРИРОДНОМУ ПАРКУ «ГОМІЛЬШАНСЬКІ ЛІСИ»

The aim of the research was to determine the ecological features and to evaluate the harmfulness of the most common xylophagous insects at the territory of the National Nature Park «Gomilshansky Forests». In deciduous forests of the National Nature Park «Gomilshansky Forests», 22 species of xylophagous insects from 16 genera of three families have been found, i.e. longhorn beetles (Cerambycidae), jewel beetles (Buprestidae) and bark beetles (Curculionidae: Scolytinae). The vast majority of species are polyphages. Five species (Xylotrechus antilope, Agrilus biguttatus, A. hastulifer, A. laticornis and A. sulcicollis) were found only in the English oak, Dicerca (Dicerca) aenea was found only in the elm, and other xylophagous insects were found in different deciduous trees. The jewel beetle Agrilus biguttatus, the bark beetles Scolytus intricatus, Xyleborus dispar, Xyleborus monographus and Xyleborinus saxeseni colonized the most vital trees. The longhorn beetle Anisorus quercus colonized drying up trees, and the longhorn beetles Poecilium alni and Prionus coriarius colonized only dead trees. Potential injuriousness of each species was evaluated considering both physioogical injuriousness and technical injuriousness. Four species (18.2 %) – A. biguttatus, S. intricatus, Xyleborus dispar and Xyleborinus saxeseni – are potentially the most harmful with the frequency of occurrence 7 %, 5 %, 1 %, and 1 % respectively. Among 9 moderately harmful species (40.9 %), the most spread are Plagionotus arcuatus, P. detritus and Saperda scalaris (11 % each). Slightly harmful are 5 species, or 22.7 %, harmless are 6 species, or 18.2 %. The data obtained are the basis for further comparing the species composition and harmfulness of xylophagous insects in the zones with different management regimes of the national nature park.

Monitoring damage caused by harmful pests in hazelnut orchards in Samegrelo region, Georgia

Hazelnut is a traditional crop of Georgia, where hazelnut growing is enlarging and export is increasing. Samegrelo is the main hazelnut producing region of the country. Unfortunately, different species of insect and mite pests have been detected in the orchards of this region, which cause quality and yield reduction of this valuable crop. In this paper we present the results of a study carried out in five villages of Samegrelo region where we surveyed the incidence of important pests. The three main pests: ambrosia beetle (Xyleborus dispar), bud mite (Phytoptus avellanae) and hazel long-horned beetle (Oberea linearis) were surveyed. X. dispar was widespread and caused considerable damage to hazelnut orchards in all five villages, while P. avellanae and O. linearis were detected in only three of the surveyed orchards. The mean number of abnormal buds and shoots damaged by these pests was not significantly different among the investigated orchards. The locations, surveying details and amount of damage is presented.

Sudden Occurrence and Harmfulness of Xyleborus dispar (Fabricius) on Pear

Summary Decline of pear trees in the region of Čačak (Serbia) is becoming a significant problem and a limiting factor in the production of this fruit species. This phenomenon may be due to the damages caused by xilophagous insects, representatives of the family Scolytidae. Economically the most important species of this family is a pear blight beetle (Xyleborus dispar), which causes symptoms of decline and/or wilting of pear trees. Such damages have not been documented so far in the region of Čačak. The aim of this study was to determine the cause of sudden appearance of pear trees decline in an orchard in this region (locality of Miokovci). The orchard has 180 trees (Stark Delicious, Santa Maria and Williams) in the sixth year of vegetation. Inspections were carried out every 30 days (20 April - 21 August 2016). Visual inspection identified X. dispar activity on 165 trees (about 92% of the trees in the orchard). Holes were registered on the trees up to a height of 160 cm and in all primary branches. The average number of entry openings on a random sample of 20 trees was 27 for the height from the soil surface to the first branch (70 cm), while it was 61 for the height up to 160 cm. The recommended treatment is eradication of pests with mandatory incineration (burning) of the collected plant material by the end of February of the following growing season. This is the first report of X. dispar as pear pests in the vicinity of Čačak.

Investigation of European shot-hole borer, Xyleborus dispar (Coleoptera, Scolytidae), in apple orchards of Latvia

European shot-hole borer is known to occur on a wide range of deciduous trees and frequently found on fruit trees in most of the Holarctic. During the last years increased activity of this beetle<em> </em>contributed necessity for investigation of it in apple orchards of Latvia. Because of the latent behavior it is difficult to control distribution of <em>Xyleborus dispar</em>. Often insecticides are not effective, especially if not used in an appropriate time and methods of integrated or biological plant protection are needed. In the current study, results of two year monitoring of <em>X. dispar</em> flying activity and effectiveness of two types of sticky traps, Rebell Rosso and Csalomon Palx, bitted with 50% alcohol are presented. Four traps of each type were placed in each orchard at the beginning of May in 2013 and at the middle of April in 2014. Differences among respective orchards were recorded: the highest number of beetles was found in the largest orchard surrounded by wide deciduous forests; the lowest number was recorded in the orchard surrounded by the agricultural lands. The first emerging <em>X. dispar</em> female was caught at the middle of April. During the vegetation season the highest flying activity of beetles was at the end of April - beginning of May (17<sup>th</sup> – 18<sup>th</sup> week). Afterwards number and flying activity of beetles decreased and at the middle of June (25<sup>th</sup> – 26<sup>th</sup> week) reached zero. In orchard with the highest number of European shot-hole borer, significantly higher number of beetles was recorded on Rebell Rosso traps; for the rest two orchards higher number of <em>X. dispar</em> was recorded on Csalomon Palx traps.

DETERMINATION OF PERFORMANCE OF DIFFERENT TRAP TYPES AGAINST Xyleborus dispar (Fabricius, 1792) AND Xyleborinus saxesenii (Ratzeburg, 1837) (COLEOPTERA: CURCULIONOIDEA: SCOLYTIDAE)

This study was carried out between the years of 2005 and 2007 at the hazelnut orchards in Terme District of Samsun Province where Bark beetles cause major loses. In this study six different trap types and two different attractant types were used against Xyleborus dispar (Fabricius, 1792) and Xyleborinus saxesenii (Ratzeburg, 1837), (Coleoptera: Curculionoidea: Scolytidae). The experiments were carried out according to the principle of randomized block design and the traps were set in 3 times of recurrence and the performance of the types of the traps were determined and compared with each other. %96 of ethyl alcohol stimulating funnel trap type has been determined as the most effective one in terms of effectiveness capturing Xyleborus dispar and Xyleborinus saxesenii. %96 of ethyl alcohol has given the best results in the stimulating traps as non-sticky properties, in the sticky traps it was determined that %96 of ethyl alcohol dilution with %1 of toluene to effect positively in defiance of the performance of traps. According to the results it was determined that out of the practiced prototype traps, the funnel-type and ribbed cage trap are specified to be more effective and practical than the red-winged traps.

Screening antibacterial activity of entomopathogenic bacteria isolated from pests of hazelnut

Thirty-seven entomopathogenic bacteria isolated from six common pests of hazelnut in the Black Sea Region of Turkey have been screened for their potential of antibacterial substance production against indicator bacteria by the agar spot assay and well diffusion assay. Results indicated that 13.5% of entomopathogenic bacteria, Pseudomonas fluorescens (Pf-Xd1), Bacillus polymyxa (Bp-Ar2), Bacillus thuringiensis (Bt-Bn1), Serratia marcescens (Sm-Mm3) and Pseudomonas flourescens (Pf-Aa4) isolated from pests of Xyleborus dispar, Anoplus roboris, Balaninus nucum, Melolontha melolontha and Agelastica alni, respectively, showed significant levels of inhibitor activities against indicator bacteria. Well diffusion assay showed that supernatants of Bp-Ar2, Bt-Bn1 and Sm-Mm3 have antibacterial activity, whereas Pf-Xd1 and Pf-Aa4 did not show any activity. Furthermore, the antibacterial activity of the substance produced by the Bp-Ar2 has a narrow spectrum, whereas those of Bt-Bn1 and Sm-Mm3 exhibit broad spectrum. The production of these antibacterial substances were similarly determined at early logarithmic phase in the growth cycle of three bacteria and continued until the beginning of the stationary phase as primer metabolite. In addition, optimal pH (at 7-9 forBt-Bn1 and 5-9 forSm-Mm3), medium (Muller Hinton broth forBt-Bn1 and Luria Bertani broth forSm-Mm3), temperature (25 ◦ Cf or Bt-Bn1 and Sm-Mm3) and production time (24h forBt-Bn1 and 72h forSm-Mm3) of these substances were determined. Our results demonstrate that entomopathogenic bacteria are a potential source of antibacterial substances.

English

Bark and ambrosia beetles (Coleoptera: Curculionidae:Scolytinae) include many important pest species of forest and fruit trees.  They usually prefer the physiologically stressed trees for colonization but also it is known that they attack healthy trees. Bark and ambrosia beetles are consisted of two main ecological groups, bark beetles grow in bark and ambrosia beetles in sapwood. Especially ambrosia beetles are very detrimental in Turkish hazelnut orchards. This study was carried out between 2005 and 2007 to monitor populations ofXyleborus dispar and Xyleborinus saxesenii (Col.: Scolytidae), causing considerable damages in hazelnut (Corylus avellana L.) orchards in Ordu and Samsun Provinces. The populations of the bark beetles were monitored using sticky traps with red wings that are registered and used to capture these pests. Ethyl alcohol (96%) was used as the attractant in the traps. The results of the three-year study indicated that both pest species emerged in different times in Ordu and Samsun. X. dispar emerged in large numbers in springs (March - May) as overwintered adults; however, X. saxesenii emerged in large numbers in summers (June - August). Population density is usually the X. dispar was found to be more.  X. dispar on 05.15.2007 (398 adult/trap), X. saxesenii on.09.01.2005 (383 adult/trap) the highest catch was recorded in Samsun province.   Key words: Hazelnut, monitoring population, Xyleborus dispar, Xyleborinus saxesenii, red winged sticky traps.

Ambrosia beetles, hosts and distribution in Turkey with a study on the species of Istanbul province

Ambrosia beetles were investigated in Istanbul province. Trap logs were used to collect the insects. In total, 4 insect species, Xyleborus dispar, Xyleborinussaxeseni, Trypodendron lineatum and Trypodendron signatum were identified in 2008. Up to date, 12 ambrosia beetles were recorded in Turkey. The faunal composition, host plants and geographical distribution of the species were discussed. Key words: Ambrosia beetles, Coleoptera, Scolytidae, Platypodidae, Turkey.

Xylophagous entomofauna in branches of oaks (Quercus spp.) and its significance for oak health in the Karst region of Slovenia

Samples of dying branches from 121 trees of Quercus pubescens, Q. cerris, and Q. petraea were taken from 102 sites in Seslerio autumnalis-Quercetum petraeae and Ostryo-Quercetum pubescentis forests. After nine months’ rearing in eclectors, branches were cut to 20-cm sections, and signs of infestation as well as larvae and adult insects were noted. We analysed 395 sections of branches from Q. pubescens, 125 sections from Q. cerris, and 85 sections from Q. petraea. We found 44 adult insects: 45% were from the Cerambycidae family (Callimus angulatus ssp. angulatus, Poecilium alni, and Exocentrus adspersus), 18% were from the Scolytinae subfamily (Scolytus intricatus, Xyleborus dispar), 4% from the Buprestidae family (Coraebus florentinus), 4.5% from the Cleridae family (Tilloidea unifasciata), and 28.5% from other families. In addition, 145 larvae were found: 50% from the Cerambycidae family, 39% from the Buprestidae family, 4% from the Scolytinae subfamily, and 7% from other families. Significant difference in the abundance of adult insects and larvae with regard to the diameter of branch sections and the host species were found. 78% of dying branches showed signs of infestation. Species of the Buprestidae, Scolytinae, and Cerambycidae represent important factors in the decline in oak vitality in the lower Karst region of Slovenia.

Identification and pathogenicity of bacteria from European shot-hole borer,Xyleborus dispar Fabricius (Coleoptera: Scolytidae)

In this study, we have isolated and identified 5 bacterial isolates from European shot-hole borer,Xyleborus dispar (Coleoptera: Scolytidae), an important pest of hazelnut. After various morphological, physiological, biochemical and molecular characteristics were determined in detail, bacterial isolates were identified asPseudomonas fluorescens (Xd1),Bacillus megaterium (Xd2),Bacillus thuringiensis (Xd3),Pseudomonas rhizosphaerae (Xd4) andPantoea cedenensis (Xd5). Especially, theB. thuringiensis strain was identified in more detail asBacillus thuringiensis subsp.tenebrionis (H8ab). The insecticidal activities were determined against the larvae ofAgelastica alni L. (Col.: Chrysomelidae),Amphimallon solstitiale L. (Col.: Scarabaeidae),Leptinotarsa decemlineata (Say) (Col.: Chrysomelidae), andMelolontha melolontha L. (Col.: Scarabaeidae) larvae at 1.8×109 CFU/ml dose, within five days. The highest insecticidal activities are 100, 100, 80 and 100% forBacillus thuringiensis subsp.tenebrionis (Xd3) onA. alni, A. solstitiale, L. decemlineata, andM. melolontha larvae, respectively. Our results indicate that especiallyB. thuringiensis subsp.tenebrionis (Xd3) may be valuable as a microbial control agent for coleopteran pests, respectively.

Highly pathogenic Bacillus thuringiensis subsp. tenebrionis from European shot‐hole borer, Xyleborus dispar (Coleoptera: Scolytidae)

The entomopathogenic bacterium Bacillus thuringiensis is the most widely used biopesticide. In this study, to find and identify the more toxic B. thuringiensis strains against coleopteran pests, we isolated a B. thuringiensis strain (Xd3) from European shot‐hole borer, Xyleborus dispar (Coleoptera: Scolytidae), a higly damaging pest of hazelnut. Based on various morphological, physiological, biochemical, and molecular characteristics, the bacterial isolate was identified as B. thuringiensis subsp. tenebrionis (morrisoni) serovar H8a8b. This isolate was compared with the reference strains by scanning electron microscopy, SDS‐PAGE analysis, cry gene content, and insecticidal activity. Isolate Xd3 forms a flat‐square inclusion containing a protein component of c. 70 kDa. PCR analysis showed that the Xd3 has a cry gene, cry3. Toxicity tests were performed against coleopteran species. One hundred percent mortality was observed against larvae of Agelastica alni (Coleoptera: Chrysomelidae). The others were 90% for Amphimallon solstitiale (Coleoptera: Scarabaeidae), and Melolontha melolontha (Coleoptera: Scarabaeidae). Our results indicate that B. thuringiensis subsp. tenebrionis (Xd3) may be valuable as biological control agent for coleopteran insects.

Beetles (Coleoptera) caught with pheromones of Gnathotrichus retusus and G. sulcatus (Col., Scolytidae) in southern Finland

AbstractThe ambrosia beetle Gnathotrichus materiarius, which originally came from North America, was discovered in southern Finland in 1996. In 1997, using Norwegian drainpipe traps baited with pheromones of Gnathotrichus retusus and G. sulcatus, we collected beetles in the region where the first specimen had been caught in order to determine whether this potential pest species had become established in the area. Samples from a total of 16 traps included 79 species of beetles and 719 individuals, but no specimens of G. materiarius. The most abundant species in the samples were the ambrosia beetles Xyleborus dispar and Trypodendron lineatum. Several predators and other associates of bark beetles were also captured. The majority of the beetles caught were saproxylic species.

Ultrastructure of the mesonotal mycangium of an ambrosia beetle, Xyleborus Dispar (F.) (Coleoptera: scolytidae)

Fungal symbionts of the ambrosia beetle, Xyleborus dispar, are transported within a glandular invagination of the body cuticle, termed the mycangium. The associated secretory cells pass their products into the mycangium via efferent cuticular ductules. Hemidesmosomes on microvilli apparently anchor the end apparatus of each ductule in the compartment. The fungal propaguXles within the mycangium are of 2 types: a small-celled fungus which is apparently the classical ectosymbiont, Ambrosiella hartigii, and a large, multinucleate propagule, which is a yeast-like basidiomycetous derivative.

Patterns of nitrogen utilization between the ambrosia beetle Xyleborus dispar and its symbiotic fungus

Some parameters of nitrogen utilization between the ambrosia beetle Xyleborus dispar in mutualistic association with its symbiotic fungus Ambrosiella hartigii, were examined. Qualitative and quantitative analyses of the major nitrogenous excretory products were made on the various life stages of X. dispar. The main nitrogenous product found in excreta and hindguts of beetles, larvae, and pupae, was uric acid (range 7·6–14·8 μg uric acid/beetle). No ninhydrin-positive compounds were located in excreta of the beetles. The concentration of ammonia-nitrogen in the various life stages averaged between 0·70 and 1·13 μg NH 3-N/beetle. Total nitrogen determinations were made on sapwood samples of Malus sylvestris (0·34 ± 0·005% N by dry weight), attacked wood, ‘pre-brood’ (0·31 ± 0·005% N by dry weight), and attacked wood ‘post-brood’ (0·17 ± 0·02% N). Similar determinations of the artificial medium ( l-asparagine medium) indicated that a nitrogen requirement of about 0·08–0·1% N by dry weight was necessary before oviposition could occur. Fixation of atmospheric nitrogen by individual X. dispar beetles in vitro was not indicated using the acetylene ethylene reductase method. Proteolytic enzyme activity was not found on examination of diapause beetles, their excreta, larval and pupal excreta, and the ambrosial and mycelial forms of A. hartigii. Comparative concentrations of soluble proteins and free amino acids suggested that fungus in the mycangia was built up from free amino acids of the insects. At the period of emergence, flight, and attack of new hosts, the females were found to have a concentration of soluble proteins more than double that found in the beetles during the remainder of the year. The free amino acids were the lowest values recorded during this period (March–October).

INTERACTIONS OF THE AMBROSIA BEETLE, XYLEBORUS DISPAR (COLEOPTERA: SCOLYTIDAE), WITH ITS SYMBIOTIC FUNGUS AMBROSIELLA HARTIGII (FUNGI IMPERFECTI)

AbstractTwo bioassays were used to study the effects of the various life stages of a Temperate Zone ambrosia beetle, Xyleborus dispar (F.) (Coleoptera: Scolytidae), on the induction of the ambrosial form of its symbiotic fungus, Ambrosiella hartigii Batra (Fungi Imperfecti).Postdiapause adults and pupae of X. dispar cause a change from the mycelial to the ambrosial form of A. hartigii in culture.Larvae feed on the mycelial form in vitro, but ambrosia is required by larvae to develop and pupate. One of the main factors inducing the ambrosial form of A. hartigii is probably a secretory product of X. dispar.