Zeitschrift für Angewandte EntomologieVolume 58, Issue 1-4 p. 319-320 Professor Dr. Viktor Butovitsch — 65 Jahre H. H. Eidmann, H. H. EidmannSearch for more papers by this author H. H. Eidmann, H. H. EidmannSearch for more papers by this author First published: January/December 1966 https://doi.org/10.1111/j.1439-0418.1966.tb04347.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume58, Issue1-4January/December 1966Pages 319-320 RelatedInformation

Field experiments were conducted in 1991 and 1992 on clear-cut and forest sites in four forest areas in southern Sweden with the aim to test possibilities for estimating pine weevil (Coleoptera: Curculionidae) population sizes. More pine weevils (Hylobius abietis andH. pinastri) were caught in baited pitfall traps than under shelter boards. The proportions ofH. pinastri in the totalHylobius catch were higher under shelter boards than in pitfall traps, indicating a difference between the species in behaviour towards the trap types. Numbers ofH. abietis found on forest sites were lower than those on fresh clear-cut sites, but not those on one year old or older clear cut sites. In mark-recapture experiments the recapture rates ofH. abietis ranged from zero to 73%; they were zero on fresh clear-cut sites. Recapture rate was not correlated to dispersal distance. Estimates of population size (Schnabel method) were in magnitudes of 150 to 5000H. abietis per hectare. The estimates did not reveal consistent differences between forest and one-year old or older clear cuttings. Dispersal distances were on average 6.0 m in 1991 and 5.4 m in 1992. Only in one area in 1992 the dispersal distances were significantly different between forest and clear-cut site.

In assessments of pine weevil (Hylobius abietis (L.)) feeding on conifer seedlings in Sweden, positive linear relationships were found between the numbers of attacked seedlings and each of the numbers of seedlings killed by pine weevil feeding, the damage score, and the mean estimated extent of feeding on damaged seedlings. Hence the damage score was described by polynomial regression on number of attacked seedlings. The influence of environmmental conditions was reflected in variations of the extent of feeding and seedling mortality. Independent assessments of the extent of feeding on an ordinal or percent scale were made by four investigators. The numbers of seedlings with feeding scars observed in field inspections were consistently lower than the actual numbers attacked. The estimates of mean extent of feeding on damaged seedlings varied between investigators within a range of about 10%. The relationship between the measured area of damaged bark and the estimated extent of feeding was expressed by linear and exponential regressions. Resume : L'evaluation des dommages causes par le charancon de l'epinette (Hylobius abietis (L.)) sur les semis de coniferes en Suede a montre qu'il y avait des relations lineaires et positives entre le nombre de semis attaques et le nombre de semis tues par le charancon, la quantite de dommages ainsi que l'intensite moyenne estimee des dommages sur les semis attaques. Par consequent, la quantite de dommages suivait une courbe de regression polynomiale par rapport au nombre de semis attaques. L'influence des conditions environnementales se refletait dans la variation de l'intensite des dommages et de la mortalite des semis. Des evaluations independantes de l'intensite des dommages sur une echelle ordinale ou en pourcentage furent effectuees par quatre observateurs. Le nombre de semis avec des cicatrices d'attaque observes lors d'inspections sur le terrain etait toujours plus faible que le nombre de semis reellement attaques. Les estimations de l'intensite moyenne des dommages sur les semis attaques variaient selon l'observateur avec un ecart d'environ 10%. La variation entre la mesure de la superficie d'ecorce endommagee et l'intensite estimee des dommages pouvait etre exprimee par des regressions lineaire et exponentielle. (Traduit par la Redaction)

Protection of seedlings afforded by two types of coated barriers (CB) against pine weevil (Hylobius species) feeding was evaluated in field experiments in Sweden. The CB is an upright sheath surrounding a seedling and covered on the outside with a coating of polytetrafluoroethylene that hinders insects from crawling up. In experiments during 1992-1993 on four sites, protective treatments by CB applied after planting greatly reduced seedling mortality due to pine weevil feeding and increased survival over two growing seasons. Seedlings with correctly positioned CB were rarely attacked. In a large-scale experiment during 1993-1994 on nine forest sites, protection by CB applied before planting reduced the risk of seedling mortality caused by pine weevil feeding by 93% in the first year and by 83% for both years. Seedling mortality due to Hylobius feeding in plots with CB protected seedlings was largely independent of the mortality in plots with unprotected seedlings. Pine weevil damage was less frequent on scarified sites than on unscarified sites. Differences in damage levels between years were partly attributed to differences in weather conditions.

The attacks of bark- and wood-boring Coleoptera on broken conifer stems after severe snow-breakage in early 1988 were studied in autumn 1988 and 1989. The study included twelve stands in the county of Varmland in central Sweden differing in age and edaphic conditions. The tops on the ground as well as the remaining rooted stem stumps of 94 Picea abies and 61 Pinus sylvestris were inspected. The presence of living branches on the stumps strongly-influenced the incidence of insect attack. All stumps without branches were attacked during the two-year period, whereas only a few spruce stumps with more than ten branches and no pine stumps with more than five branches were attacked. On spruce stumps, the most frequently encountered Coleoptera were all scolytids, i.e. the species Pityogenes chalcographus, Hylurgops palliatus, and the genera Polygraphus, Dryocoetes, and Trypodendron. On pine stumps, Tomicus piniperda was the most common species. Most of the spruce tops and virtually all pine tops were attacked during the two-year period, and most of these attacks occurred during the first summer. P. chalcographus, Dryocoetes, and weevils of the genus Pissodes were the most frequent Coleoptera on spruce tops. On pine tops, the dominant insects belonged to the genera Pissodes and Pityogenes.

The impacts of bark beetles in Sweden and the role and management of bark beetle breeding substrate are discussed. Of the six important species damaging living trees, Tomicus piniperda and Ips typographus have the greatest impact. The damage caused by Tomicus adults feeding in pine shoots is directly related to beetle numbers, which in turn depend on the availability of non-resistant breeding substrate. Intensity of shoot pruning, tree size, and geographic region are important factors determining the extent of losses, which can amount to 45 % of the annual volume growth. The extent of tree mortality caused by Ips typographus attack depends on interactions between host tree vigour, densities of colonizing populations, and the availability of other, non-resistant breeding substrate. During the latest outbreak, the trees killed represented about 6 million cubic meters of wood. The heaviest losses were reduction of timber quality, unsalvaged timber, and the cost of control measures. The economic impact of reduced growth depends on the shortening of rotation by insect attack and on interest rates. During the 1960s and 1970s bark beetle attacks and their impact increased owing to natural causes and forestry practices. Hereafter, integrated forest protection efforts, based on research, organisation, information, and legislation, reduced bark beetle attacks to a low level.

Host recognition and aggregation behaviour in the black spruce beetle, Hylastes cunicularius Erichson, were studied in choice experiments in the laboratory. The beetles tended to aggregate. Aggregation occurred at host material or at beetles and was independent of the sex of the beetles. Hidden host material was found by active host orientation. The beetles were attracted by several conifer species. In some experiments the beetles preferred the main host, Norway spruce, but Scots pine was also readily accepted. Sections of roots were chosen more often than stem sections. Fresh cuts on the host material enhanced attraction. No evidence was found to indicate the presence of an aggregation pheromone.

The response of adult Hylobius abietis L. before and after the spring flight period and in autumn to host volatiles was studied in field experiments using pitfall traps and trapping billets. In spring and early summer, pitfall traps baited with alpha-pinene + ethanol caught more pine weevils than traps baited with pine stem pieces. In autumn, the reverse was true. In autumn, newly emerged prereproductive females were caught in pine baited traps and at trapping billets, but not in traps baited with alpha-pinene + ethanol. In spring before the flight period, traps baited with alpha-pinene + ethanol caught similar numbers of prereproductive and reproductive females, whereas nearly all females caught in pine baited traps and at trapping billets were prereproductive. The differences in responses to olfactory stimuli between phases of the adult life cycle reflect seasonal differences in behaviour and should be taken into account in trapping methods based on olfactory orientation, particularly methods for population estimates.

The composition of volatile wood constituents in healthy (untreated) and injured (top-cut or girdled) Scots pine trees, Pinus sylvestris L., was studied during three years using gas chromatography. The data were evaluated using PCA (principal components analysis) and PLS-DA (projections to latent structures-discriminant analysis), two methods for multivariate data analysis. Data from headspace analysis from the first and the third year revealed a significant difference in the composition of volatile wood constituents between untreated and top-cut trees while GC analysis of extracts only revealed a significant difference for the first year. The higher proportions of ethanol and acetaldehyde in top-cut trees were important in differentiating these trees from healthy ones. Differences in the monoterpene composition also seemed to be important in this respect. Untreated trees remained unattacked by the scolytid species. Hylurgops palliants (Gyll.) and Trypodendron lineatum (Oliv.) (Scolytidae) only attacked top-cut trees, which were characterized by relatively high proportions of ethanol and acetaldehyde. Tomicus piniperda (L.) attacked both top-cut and girdled trees, which were in some, but not all cases also characterized by relatively high proportions of ethanol and acetaldehyde.

AbstractDuring an outbreak of the East Himalaya spruce bark beetle, Ips schmutzenhoferi, large numbers of conifer trees have been killed, mainly Picea spinulosa. The beetle species was studied in laboratory rearing experiments at 20 °C in Sweden on its natural host and on P. abies. Data were obtained on the duration of development, course of emergence, production of young adults, and sex ratio. The laboratory studies were supplemented by field observations in Bhutan. The emergence of young adults culminated 68 days after colonization of the breeding substrate began and 14–29 days after the first offspring emerged. The parent beetles left the breeding substrate earlier. 1300–2500 young adults were produced per m2 breeding substrate, corresponding to 1.5–9.7 beetles per egg gallery. 43 % of the emerged young adults were males, whereas during colonization and breeding the male proportion was about 27%. The results are compared with data on I. typographus and discussed with respect to conditions influencing the population dynamics of the species.ZusammenfassungEntwicklung und Vermehrung des Osthimalaya‐FichtenborkenkäfersIn einer Gradation im Königreich Bhutan hat der Osthimalaya‐Fichtenborkenkäfer Ips schmutzenhoferi auf großen Flächen Nadelbäume befallen und getötet, besonders Picea spinulosa. In Laboratoriumszuchten bei 20 °C in Schweden auf dem natürlichen Wirt und auf P. abies, ergänzt durch Freilandbeobachtungen in Bhutan, wurden Entwicklungsdauer, Verlauf des Auskriechens, Produktion von Jungkäfern und Geschlechterverhältnis studiert.Der Höhepunkt des Auskriechens der Jungkäfer aus dem Brutmaterial traf 68 Tage nach Beginn der Bruttätigkeit und 14–30 Tage nach Beginn des Auskriechens ein. Die Elterntiere verließen das Brutmaterial früher. Die Produktion von Jungkäfern betrug 1300–2500 Jungkäfer pro m2 Mantelfläche oder 1,5–9,7 Jungkäfer pro Muttergang. 43 % der ausgekrochenen Jungkäfer waren Männchen; bei der Kolonisierung und dem Brüten lag der Anteil der Männchen um 27 %.Die Ergebnisse werden im Vergleich mit Daten von I. typographus und in Hinsicht auf die Populationsdynamik besprochen.

Der im Königreich Bhutan erheblich schädliche, jüngst vonIps longifoliaStebb. abgetrennteIps schmutzenhoferiHolzsch. produziert ein Aggregations-Pheromon, über dessen Untersuchung ein vorläufiger Kurzbericht gegeben wird. Die im Enddarm der Käfer lokalisierten Duftstoffe wurden mittels der GC-MS-Analyse identifiziert. Unter ihnen befinden sich einige bereits von anderen Borkenkäfern bekannte Verbindungen wie: Ipsenol, Ipsdienol undcis-Verbenol. Daneben fanden sich mehrere bekannte Verbindungen und ein noch unbestimmtes oxygeniertes Monoterpen (Tab. 1). Die vonI. typographus bekannte Komponente 2-Methyl-3-buten-2-ol wurde bisher nicht entdeckt. Ipsdienol allein und in Mischungen mitcis-Verbenol bewirkte Angriffe von1. schmutzenhoferi auf stehende Fichten. Aus den bisherigen Ergebnissen wird geschlossen, daß eine oder mehrere der festgestellten Verbindungen als Komponenten einer synthetischen Mischung zur Anlockung dieses Borkenkäfers verwendet werden können.

In a trapping experiment, wood chips from freshly cut Scots pine trees attracted flying adults of the bark beetleTomicus piniperda (L.) Healthy Scots pine trees, which usually are not attacked byT. piniperda, were baited with chips from freshly cut trees. In other experiments trees were baited with a mixture of (−)-α-pinene, (+)-3-carene, and terpinolene; the individual monoterpenes; or with ethanol alone. All baited treatments were attacked byT. piniperda. Most of the attacks resulted in short egg galleries and in larval galleries which were only a few millimeters in length. In trees from which a new generation of beetles emerged, net reproduction was well below 1.0. Unbaited control trees remained unattacked or received a few isolated attacks.

In field experiments in Sweden, the constituent 2-methyl-3-buten-2-ol of the aggregation pheromone of the spruce bark bettleIps typographus (L.) was effectively replaced by 2-methyl-3-butyn-2-ol.

AbstractInsects attacking logs of exotic conifers in SwedenInsect attack on logs from 25‐year‐old trees of 22 species in the genera Picea, Abies, Larix, and Pseudotsuga was studied in the province of Östergötland in Sweden. Attacks by the bark beetle Pityogenes chalcographus predominated, more rarely occurred Ips typographus. All other frequently found insects were typically secondary species with broad host ranges, i.e. Hylurgops palliatus, Dryocoetes autographus, Trypodendron lineatum, and Rhagium inquisitor. The intensity of insect attack varied between tree species and genera. The Abies species were least attacked. Abies, Larix, and Pseudotsuga were less frequently attacked by P. chalcographus and were less suitable as breeding substrate for this bark beetle than was Picea.ZusammenfassungAn Stammabschnitten 25jähriger Bäume von 22 Arten der Gattungen Picea, Abies, Larix und Pseudotsuga wurde der Befall und die Vermehrung von holz‐ und rindenbrütenden Insekten untersucht. Die häufigste Art war Pityogenes chalcographus, seltener war Ips typographus. Alle anderen häufig gefundenen Insekten gehörten zu solchen Arten, die ausgesprochen sekundär auftreten und ein breites Wirtsspektrum haben, nämlich Hylurgops palliatus, Dryocoetes autographus, Trypodendron lineatum und Rhagium inquisitor. Die Baumarten und Gattungen unterschieden sich in der Stärke des Insektenbefalls voneinander. An den Abies‐Arten kamen die wenigsten Insekten vor. Die Gattungen Abies, Larix und Pseudotsuga waren weniger von P. chalcographus befallen als Picea und eigneten sich auch weniger als Brutmaterial.

Field tests using pitfall traps were conducted to test the relative attractiveness of conifer volatiles and ethanol to Hylobius abietis (L.). Traps baited with stems of Scots pine, Pinus sylvestris L., plus ethanol caught about twice as many weevils as those with stems alone. When tested separately, α-pinene, a terpene blend, and ethanol were much less attractive than ethanol combined with any of the terpene treatments.

AbstractAdults of Hylobius abietis (L.) (Coleoptera: Curculionidae) were found to locate conifer roots suitable for oviposition by utilizing host volatiles diffusing through the soil. Underground sources of host volatiles were presented to weevils in a laboratory bioassay. A cold‐trapping condensate of Scots pine, Pinus sylvestris L., and fractions of it were tested. Various fractions containing host terpenes attracted weevils in the bioassay, but the complete pine condensate caused the highest response. Ethanol was also found to be attractive. Weevils caged underground in the absence of host material did not attract weevils on the surface.ZUSAMMENFASSUNGDie Orientierung des Russelkäfers Hylobius abietis zu unterirdischen Quellen flüchtiger Inhaltsstoffe des WirtsmaterialsRüsselkäfer (Hylobius abietis) können auf der Erdoberfläche die Lage im Boden verborgenen Brutmaterials feststellen und Wurzeln senkrecht grabend auffinden. Mit einer neu entwickelten Methode für Laborversuche, die sich auf die spezifische Reaktion des Eingrabens zum Brutmaterial gründet, wurden das Orientierungsverhalten der Käfer und die zum Brutmaterial führenden Geruchsstoffe des Wirtes studiert.Beide Geschlechter von H. abietis reagierten gleichartig mit Eingraben auf die Geruchsstoffe des Wirtes. In Wahlversuchen zwischen gleichwertigen Anlockungspunkten kam häufig Aggregation der Käfer an einem Punkt vor. Die stärkere Ansammlung an einzelnen Stellen stand im Zusammenhang mit dem Vorhandensein einer Erdröhre zur Quelle der Geruchsstoffe. In den folgenden Versuchen wurde deshalb den Tieren jeweils nur eine Geruchsstoffquelle angeboten. Weder Weibchen noch Männchen im Boden übten eine Anziehung auf Käfer an der Oberfläche aus.Kiefernstücke und Kondensate fluchtiger Kieferinhaltsstoffe sowie Kondensat nach Passage durch die Kolonne des Gaschromatographen waren stark attraktiv. Alle durch präparative Gaschromatographie hergestellten Fraktionen des Kondensats waren ebenfalls, aber schwächer attraktiv. Zehnfache Verdunnung des Kondensats und der Fraktionen verminderte ihre Attraktivität mit etwa 40–70%. Auch äthanol, Methanol und Pentan wurden geprüft; nur äthanol hatte eine mässig anlockende Wirkung.

Field tests were conducted with Hylobius abietis (L.) in Sweden during 1982 and 1983 to study how weevils feeding on host material affect attractivity of this host material to other H. abietis Pitfall traps baited with a combination of male or female weevils and cut stems of Scots pine caught more weevils of both sexes than pine alone. Weevils of either sex were not attractive in absence of host material. Attractivity of ground phloem containing weevil frass was not significantly different from that of ground phloem alone. In a laboratory test, feeding by weevils of either sex on pine about doubled the release of monoterpene hydrocarbons and ethanol compared with pine alone. Existence of an aggregation pheromone could not be confirmed. We suggest that weevil aggregations are formed in response to host volatiles and that weevil feeding increases amounts of these volatiles released.

AbstractFree‐living adults and immature stages (in stem sections) of the bark beetle species Ips typography, Pityogenes chalcographus and Tomicus piniperda were exposed to continuous flows of atmospheres containing carbon dioxide, nitrogen, compressed air and combinations of them.Adults and immature stages of P. chalcographus and I. typographus tolerated the various atmospheres different from air better than did T. piniperda. Exposure to atmospheres containing high concentrations of carbon dioxide in combination with low concentrations of oxygen caused the highest mortality in adults. Longer exposure times were required to achieve the same mortality in immature stages in stem sections as in free‐living adults.ZusammenfassungDer Einfluß reiner und gemischter atmosphärischer Gase auf das Überleben von drei BorkenkäferartenFreilebende Imagines und Jugendstadien (in Stammabschnitten) der Borkenkäferarten Ips typogra‐phus, Pityogenes chalcographus und Tomicus piniperda wurden gleichmäßigen Gasströmen von Atmosphären aus Kohlendioxyd, Stickstoff oder Druckluft und deren Mischungen ausgesem.Die Imagines und Jugendstadien von P. chalcographus und I. typographus ertrugen die von Luft abweichenden Atmosphären besser als T. piniperda. Atmosphären mit hohen Konzentratio‐nen von Kohlendioxyd in Kombination mit geringem Sauerstoffgehalt verursachten bei den Imagines die höchste Sterblichkeit. Die Jugendstadien in Stammabschnitten mußten länger exponiert werden, um dieselbe Sterblichkeit wie bei den Imagines zu erzielen.

A GC/MS analysis of the volatile constituents from the flowers of Norway Spruce, Picea abies, has been carried out. The volatile constituents of the female flowers were distinctly different from those of the male flowers and the twigs. Characteristic constituents are methyl and ethyl benzoate, methyl and ethyl salicylate, methyl and ethyl butanoate, borneol and bornyl acetate. In the scent from the male flowers we could only detect the same monoterpenes as in the twigs. In Larix sibirica methyl benzoate, methyl salicylate, borneol and bornyl acetate were detected in the female flowers and, in the female flowers of Pinus sylvestris, methyl salicylate was found.