Comparison of seasonal responses ofHylobius abietis (L.) (Col., Curculionidae) to chemical and natural lures in baited pitfall traps

Differences in catches ofHylobius abietis (L.) adults in baited pitfall traps with chemical (alpha-pinene, ethanol, water) and natural (spruce billets, water) lures were found not in the over-all number of trapped adult weevils, but in the per cent occurrence and number of old and young beetles in individual periods of the season.     

Pine Weevil Population Density and Damage to Coniferous Seedlings in a Regeneration Area With and Without Shelterwood

Damage to planted conifer seedlings by the pine weevil, Hylobius abietis (L.), is considered to be less severe in shelterwoods than in clear-cuttings. To evaluate possible reasons for this reduction, this study investigated the relationship between seedling damage and pine weevil population density in the presence and absence of shelter trees. Assessments of seedling damage throughout a full growth season and absolute population density estimates were made at a fresh clear-cutting and an adjacent shelterwood (1 ha each). A grid of 100 pitfall traps was placed over each area, and population estimates were made using the mark–recapture technique. Pine weevil damage to seedlings was about twice as high in the clear-cutting, whereas pine weevil density was estimated to be higher in the shelterwood or about the same in the two treatments (～14?000 weevils ha^?1). Existing differences in microclimate between the shelterwood and clear-cutting did not seem to be the cause of the differences in damage levels. Thus, the hypothesis that seedling damage is reduced in shelterwoods because of increased availability of alternative food remains a candidate for further testing.     

Entwicklung von Hylobius abietis L. (Col., Curculionidae) in Fichten- und Kiefernrindenhaufen bei München

For the purpose of studying the fauna of Coleoptera living in bark clusters caused by debarking machines near Munich in 1977 in one of these clusters 2600 old larvae ofHylobius abietis L. m³ were found. Also clusters of pine bark containedH. abietis larvae but only a few ones. The mechanical growed bark clusters are a new type of habitat ofHylobius in the forests of Middle Europe.     

Height growth of planted conifer seedlings in relation to solar radiation and position in Scots pine shelterwood

Seedlings of different provenances of Scots pine (Pinus sylvestris L.), lodgepole pine (Pinus contorta Dougl., var. latifolia Engelm.) and Norway spruce (Picea abies (L.) Karst.) were planted in three Scots pine shelterwoods (125, 65 and 43 stems ha⁻¹) and a clear-cut, all in northern Sweden. The sites were mounded and planting took place during 2 consecutive years (1988 and 1989). The solar radiation experienced by the individual seedlings was determined using a simulation model. Height development of the seedlings was examined during their first 6 years after planting. During the final 3 years of the study, height growth of Norway spruce was relatively poor, both in the shelterwoods and the clear-cut area. Height growth of lodgepole pine was significantly greater than that of Scots pine, both in the shelterwoods and the clear-cut. In contrast to Norway spruce, Scots pine and lodgepole pine displayed significantly greater height growth in the clear-cut than in the shelterwoods. For all three species in the shelterwoods, regression analyses showed that height growth was more strongly correlated with the distance to the nearest tree than with the amount of radiation reaching the ground, i.e. growth was reduced in the vicinity of shelter trees. Therefore, we conclude that the significant reduction in height growth of seedlings of Scots pine and lodgepole pine in Scots pine shelterwoods was partially caused by factors associated with the distance to the nearest shelter tree. Because the substrate was a nitrogen-poor sandy soil, we suggest that root competition for mineral nutrients, especially nitrogen, accounts for the reduction in height growth.     

Field evidence for the large pine weevil,Hylobius abietis as a vector of Heterobasidion annosum

Mycological analysis of the excrements of adult weevils (Hylobius abietis L.), trapped in the baited pitfall traps in South Bohemia, Czechosovakia, demonstrated the presence of viable spores which suggest a positive role of the weevils as vectors of H. annosum.     

Beifänge in Borkenkäfer-Pheromonfallen in Nord-Griechenland

13 Röchling Pheromone traps were used in a pine forest in Thessaloniki, N. Greece. The synthetic pheromones Pheroprax, Linoprax, CME 1986 519.66 and CME 1988 619.02 were placed in the traps. As side captures 24 species of insects were caught by the traps. Total 867 individual predators were captured in the 13 traps. In average 33 specimens ofThanasimus formicarius (L.) (Cleridae) and 30 specimens ofAulonium ruficorne (01.) (Colydiidae) were caught per trap.     

Temporal patterns of seedling mortality by pine weevils (Hylobius abietis) after prescribed burning in northern Sweden

Damage by the large pine weevil, Hylobius abietis (L.), is a major threat to conifer plantations throughout Eurasia, but damage is usually less severe in northern areas. However, pine weevil damage seems to increase if the sites are burnt. The aim of this study was to determine the effects of variations in the time of planting (with respect to the total age of the clear-cut and the time since burning) on pine weevil damage to seedlings on burnt sites in northern Sweden. The study also explored whether there is an optimal time for planting at which damage levels are reduced to acceptable levels. Ten sites were selected in an inland area of northern Sweden where pine weevils are normally scarce. The sites were dry–mesic and represented a range of times since clear-cutting and since burning. The sites were planted in June 1998, 1999 and 2000 with 1-year-old container-grown seedlings of Norway spruce [Picea abies (L.) Karst.]. Pine weevil damage was reduced if planting was done no earlier than 3 years after clear-cutting and no earlier than 2 years after burning. Planting too soon after burning, irrespective of the age of the clear-cut, resulted in unacceptably high damage levels.     

Within- and between-stand distribution of attacks by pine weevil [Hylobius abietis (L.)]

The pine weevil (Hylobius abietis L.) is considered one of the most damaging pests in reforestation areas in Scandinavia. The purpose of this study was to ascertain the within- and between-stand distribution of pine weevil attacks. Between-stand distribution was examined by assessing the frequency of attacks in all newly planted coniferous stands in relation to stands clear-cut at two state forest districts in North Zealand, Denmark. Within-stand distribution was examined by investigating the position and damage to individual seedlings in relation to the position of breeding material. The stand-level attack frequency did not seem to be higher for stands in areas with more clear-cuts. The within-stand distribution of attacks was not influenced by the position of breeding material.     

Colonization and lignin decomposition of pine needle litter by Lophodermium pinastri

The colonization and lignin decomposition of pine (Pinus thunbergii and Pinus densiflora) needle litter by an endophytic fungus, Lophodermium pinastri, was examined with field observations, a field experiment and laboratory experiments. In pine needles collected from the field, needle mass per length and lignin content were lower in needle portions bearing Lophodermium fruiting bodies than in the remaining needle portions, whereas total carbohydrate content was not different between them. Total and live hyphal lengths were greater in needle portions bearing Lophodermium fruiting bodies than in the remaining needle portions. Lophodermium fruiting bodies were not formed on sterilized needles after a 6‐month incubation on the forest floor, whereas they formed on 20% of non‐sterilized needles, indicating that this fungus can only colonize live needles on the branch. In pure culture decomposition tests, mass loss of lignin was detected for several isolates of L. pinastri, but was variable among isolates and between the needles of two pine species. A comparison of the rDNA‐internal transcribed spacer sequences between L. pinastri isolates of P. thunbergii and P. densiflora indicated that the two groups were phylogenetically separated. This study is the first to show that L. pinastri has the ability to decompose lignin in dead pine needles.     

Variation in the relative abundance of the large pine weevil among Sitka spruce plantation sites

Between 1993 and 1994 over 160 forest sites were sampled toobtain indices of pine weevil (Hylobius abietisL.) densities.Overall 48 variables were tested for their ability to explainvariation in weevil numbers between compartments. The modelsgenerated from the sample data identified 14 variables as significantin influencing weevil densities. In this research note the variablesare identified, and their relationship to forest managementdiscussed     

MonitoringHylobius abietis (L.) (Col., curculionidae) by baited pitfall traps in relation to planting and treatment of seedlings in a re-forested area

The method of standardized baited pitfall, traps for monitoring population ofHylobius abietis (L.) was experimentally included into the routine planting and control schedule (model area) in the Czech Republic. It is recommended to determine characteristics of the area on the basis of long-term monitoring. A short-term prognosis per site must be drawn from monitoring done from the earliest beginning of the season. However, it seems advisable to treat all the individual seedlings immediately after theyhave been planted in the area where the over-all characteristics (ascertained by monitoring) indicate generally high population levels. To base a decision for treatment on the percentage of seedlings attacked (feeding scars) per site is considered unadvisable in comparison with data obtained bymonitoring using baited pitfall traps. Insecticides for the treatment of newly planted seedlings need to be applied to two-thirds of the trunk of a seedling (including the root collar), their action should be fast enough to paralyse (kill) the weevils before they reach xylem by feeding and, furthermore, the residues should be effective up to the end of the season.With one figure and 3 tables     

Diversity of ophiostomatoid fungi associated with the large pine weevil, Hylobius abietis, and infested Scots pine seedlings in Poland

Context

Bark beetles are known to be associated with fungi, especially the ophiostomatoid fungi. However, very little is known about role of pine weevils, e.g., Hylobius abietis, as a vector of these fungi in Europe.

Aims

The aims of our study were to demonstrate the effectiveness of H. abietis as a vector of ophiostomatoid fungi in Poland and to identify these fungi in Scots pine seedlings damaged by weevil maturation feeding.

Methods

Insects and damaged Scots pine seedlings were collected from 21 reforestation sites in Poland. The fungi were identified based on morphology, DNA sequence comparisons for two gene regions (ITS, β-tubulin) and phylogenetic analyses.

Results

Sixteen of the ophiostomatoid species were isolated and identified. In all insect populations, Leptographium procerum was the most commonly isolated fungus (84 %). Ophiostoma quercus was also found at a relatively high frequency (16 %). Other ophiostomatoid fungi were found only rarely. Among these rarer fungi, four species, Leptographium lundbergii, Ophiostoma floccosum, Ophiostoma piliferum and Sporothrix inflata, were isolated above 3 %. L. procerum was isolated most frequently and was found in 88 % of the damaged seedlings. S. inflata was isolated from 26 %, while O. quercus occurred in 10 % of the seedlings.

Conclusion

This study confirmed that L. procerum and O. quercus were common associates of H. abietis, while others species were found inconsistently and in low numbers, indicating causal associations. H. abietis also acted as an effective vector transmitting ophiostomatoid species, especially L. procerum and S. inflata, to Scots pine seedlings.     

Source,distribution and abundance of macroarthropods on the bark of longleaf pine: potential prey of the red-cockaded woodpecker

Arthropod diversity, abundance and biomass on 50–70-year-old longleaf pine (Pinus plalustris) tree boles were examined to determine the origin of the prey available to the endangered red-cockaded woodpecker (Picoides borealis) and the variability of this prey over time. Traps designed to capture arthropods crawling on the bark (crawl traps), alighting on the bark (flight traps), and crawling on the ground (pitfall traps) were operated continuously for 12 months. Flight and crawl traps were placed at different heights. One-half of the trees with crawl traps were fitted with a barrier to prevent arthropods from crawling up from the ground. Arthropods were identified to genus from one weekly sample per month and subsamples were oven-dried and weighed to estimate biomass. The arthropod community on the bark included over 400 genera. Crawl trap captures were the most similar to the prey of P. borealis. Arthropod fauna captured in crawl traps had a 58% similarity to pitfall trap captures and a 60% similarity with flight trap captures. Flight and pitfall trap captures had a 10% similarity. Barriers to arthropod movement up the tree reduced the arthropod biomass on the bole of the trees by 40–70%. Arthropod biomass was relatively evenly distributed over the tree, but varied seasonally with the highest biomass captured in the fall of the year. In general, the study showed that little of the arthropod biomass on the bark is in the form of arthropods that live exclusively in that habitat and that a large portion of the biomass is crawling up from the soil/litter layer.     

The development of Lophodermium pinastri in conifer nurseries and plantations in North America

The recent outbreak of Lophodermium needlecast in North America first appeared in 1966 in forest nurseries on red pine (Pinus resinosa) and Scotch pine (P. sylvestris). Dispersal of infected nursery stock throughout North America has created a serious needlecast problem in Scotch pine Christmas tree plantations. Two biotypes of L. pinastri are present. The pathogenic strain may be a recent introduction. The fungicides maneb and chlorothalonil are being used for control.     

Evict or infect? Managing populations of the large pine weevil, Hylobius abietis, using a bottom–up and top–down approach

Hylobius abietis is the most important pest of replanted coniferous sites in Northern Europe, where feeding by adult weevils can result in up to 100% mortality of seedlings. Field trials were conducted with the aim of reducing H. abietis populations developing in Sitka spruce stumps by increasing pressure from natural enemies (top–down pressure), and reducing the quality of stumps for development (bottom–up pressure). Top–down pressure was applied through inundative treatment of stumps with entomopathogenic nematodes (Heterorhabditis downesi or Steinernema carpocapsae). Bottom–up pressure was applied by treating stumps with the wood colonising fungus Trichodermakoningii. Natural levels of parasitism of H. abietis by the parasitoid Bracon hylobii and the effect of applied agents on B. hylobii were also investigated. Heterorhabditis downesi parasitised more immature weevils than S. carpocapsae, and significantly reduced numbers of adults emerging from stumps compared to controls. Entomopathogenic nematodes did not significantly impact on populations of B. hylobii, and over three sites the effects of both agents were additive. Stumps modified by application of the fungus (bottom–up pressure) did not have fewer H. abietis developing in, or emerging from them; however, development of H. abietis was more advanced in these stumps, and the success of natural enemies was differentially affected. T.koningii facilitated B. hylobii while having the opposite effect on entomopathogenic nematodes, suggesting that it affected the outcome of competition between the nematodes and the parasitoid.     

Zur Überwachung und Prognose bei der Nonne,Lymantria monacha L. auf Pheromon-Basis

The dynamic of a population of the nun moth (L. monacha) was monitored by the aid of pheromone traps for four years in a pine forest in Bavaria. During this time the population ofL. monacha came from the latency to an outbreak. In this way it was possible to show a correlation between the trapped moths and the density of the population for each phase of the gradation. From this results it could be concluded that about 60–70 males per trap and night (maximum) signify a critical threshold value. A method to predict the development of a nun moth population by pheromone traps is proposed.     

光肩星天牛种群扩散规律的研究

为了探讨光肩星天牛成虫在自然界中种群扩散的模式和种群数量变动等问题,在甘肃省永靖县采用标记-回捕的方法进行了光肩星天牛的扩散规律研究。系统收集了光肩星天牛成虫种群在时间序列过程中的扩散资料,按照动态分析方法,对天牛成虫在杨树农田林网中的扩散规律进行了研究,并对影响天牛成虫扩散的因子进行了分析。结果表明:种群扩散有明显的方向性,由环境因素引起。对气象因素分析表明扩散格局主要受风向影响,各方向的回收数量都与其相同风向呈负相关,而与相反风向呈正相关,但与风速、温度和相对湿度关系不密切。成虫的扩散密度随距离和时间     

Damage by pine weevil Hylobius abietis to conifer seedlings after shelterwood removal

Abstract

Pine weevil (Hylobius abietis L.) damage to seedlings after overstorey removal was investigated in a survey study in six shelterwoods in the south–central part of Sweden. The shelterwoods predominantly consisted of Scots pine, except at one site where the shelter trees mainly consisted of Norway spruce. Before final cutting, 10 plots were laid out at each site and measurements of shelter trees and marked seedlings were taken. The seedlings were examined during the 2 years after final cutting. The study showed that removal of shelter trees increases the risk of severe damage by pine weevil and the variable that was most strongly correlated with the risk was the seedling root collar diameter. Both Scots pine and Norway spruce seedlings were severely damaged by pine weevil, and most of the feeding occurred during the first year after cutting. The amount of debarked area was significantly larger for Scots pine than for Norway spruce seedlings. Vitality (growth of the leading shoot before final cutting) of the seedlings also affected the probability of damage. Seedlings with high vitality were less damaged by pine weevil than seedlings with low vitality. For Scots pine the shelterwood density before final cutting was correlated to the intensity of pine weevil feeding after cutting. In conclusion, after the final cutting of a pine or spruce shelterwood, pine weevils will probably invade the area. To avoid serious damage, Norway spruce and Scots pine seedlings should have reached a diameter of at least 10–12 mm.     

Response of ground beetles (Coleoptera: Carabidae) to forest gaps formed by a typhoon in a red pine forest at Gwangneung Forest,Republic of Korea

In Korea, damaging typhoons related to climate change have increased steadily since the 1990s. Red pine (Pinus densiflora) forests in Gwangneung Forest were greatly disturbed by typhoon Kompasu in 2010. A survey was carried out to clarify differences in ground beetle (Coleoptera: Carabidae) communities between forest gaps and undamaged forests. Ground beetles were sampled using pitfall traps from early May to late October 2011. Vegetation changes, litter layer, organic matter layer, and soil conditions were also measured. A total of 1035 ground beetles of 32 species were collected. Contrary to our expectation, species richness, abundance, and community structure of the ground beetles in forest gaps were similar to those in undamaged forests. Species richness and abundance of habitat type were also similar. However, species diversity and estimated species richness in forest gaps were significantly higher than in undamaged forests. These findings suggest that forest gaps formed by a typhoon did not lead to great change in ground beetle communities.     

Carabidae (Insecta,Coleoptera) im Kulturland des Innsbrucker Mittelgebirges (900 m NN,Nordtirol, Österreich)

Activity and distribution of Carabidae were studied in montane field habitats near Innsbruck mainly in 1974–1976. Catches by water traps were almost negligible, but contained some species foraging also in the field layer (e. g.Amara, Dromius). Results with pitfall traps (52spp., ca. 3,150 specimens) on spccies composition and seasonal occurrence. fit well with the literature on Carabidae in agricultural and meadow habitats in lower regions of mid-Europe, esp. Germany. Nevertheless, these are strong differences in dominance values. The montane fields studied show a striking difference in faunal composition against the nearby forest, with strong interrelations between the sites themselves. Carabid diversity was low in a meadow, though rather stabile in four years of observation, and highest in a crop field.