Associations between Tomicus destruens and Leptographium spp. in Pinus pinea and P. pinaster stands in Tuscany,central Italy

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.     

Blue stain fungi associated withIps cembrae (Coleoptera: Scolytidae) in Japanese larch in connection with their brood development

The association between blue stain fungi andIps cembrae Heer (Coleoptera: Scolytidae) was investigated in the Japanese larch,Larix leptolepis Gordon, in the Nagoya University Forest, Aichi Prefecture, central Japan.I. cembrae had one or two generation(s) in a year in this study area. Two blue stain fungi,Ophiostoma piceae andLeptographium sp., were isolated from the body surface of both male adults in mating chambers and female adults in parent galleries, suggesting that this beetle species was a vector of these fungi. Although no blue stain fungi were isolated from non-stained wood, both fungi were isolated from the mating chambers, the center and the uppermost end of the galleries throughout the season. The fact thatO. piceae was consistently isolated with high frequency from adults and from their galleries strongly suggested that this species would be the principal blue stain fungus infecting the beetle-attacked larch trees.     

Mountain pine beetle‐associated blue‐stain fungi in lodgepole × jack pine hybrids near Grande Prairie,Alberta (Canada)

The mountain pine beetle (MPB), the most serious pest of lodgepole pine in mountainous western Canada, spread northeastward into lodgepole × jack pine hybrids in the boreal forest of Alberta in 2006. The MPB vectors three species of blue‐stain fungi, which contribute to the success of the beetles. These fungi were isolated from MPB larvae and galleries in several lodgepole × jack pine stands in the Grande Prairie region of northwestern Alberta in autumn 2006 and winter and spring 2007. Fungi were recovered from more than 95% of gallery systems. The three fungi were similarly prevalent but Ophiostoma montium was the most frequently isolated fungus at each sampling point, isolated from 72% to 90% of gallery systems compared with 63% to 78% for Grosmannia clavigera, and 61% to 86% for Leptographium longiclavatum. Ophiostoma montium and G. clavigera were isolated from more larvae than gallery samples, with the opposite true for L. longiclavatum. Most gallery systems contained multiple fungi with three fungi per gallery system being more common in autumn and winter and two fungi more common in the spring. The combination of G. clavigera and L. longiclavatum was less common among gallery systems with two fungi than either of the pairwise combinations containing O. montium. Fungal prevalence was the same above and below snow level. The prevalence of the three fungi did not differ significantly among stands sampled in the spring but stands with more G. clavigera tended to have less L. longiclavatum. The winter of 2006–2007 was colder than average throughout Alberta with temperatures below ?30°C in November, January and February, and all three fungi were present after the cold winter while most larvae had died, suggesting that overwintering mortality of the fungi will not limit persistence and spread of MPB in the boreal forest.     

Comparisons of Ophiostomatoid fungi associated withTomicus piniperda andT. minor in Japanese red pine

Five species ofOphiostoma, twoLeptographium species and aGraphium species were isolated from two morphologically and ecologically similar bark beetle species,Tomicus piniperda andT. minor, and their infested Japanese red pine (Pinus densiflora) in Yamanashi Prefecture, central Honshu, Japan. An underscribedOphiostoma species andO. minus were isolated mainly fromT. piniperda and its galleries.Ophiostoma canum which was found for the first time in Japan was mainly fromT. minor and its galleries. Specific relationships between the beetles and fungal species are suggested. Contribution No.140, Laboratory of Plant Pathology and Mycology, Institute of Agriculture and Forestry, University of Tsukuba. Part of this study was presented at 108th Annual meeting of Japanese Forestry Society, April 2, 1997, Fukuoka, Japan.     

Control of the Large Pine Weevil and Bark Beetles of the Genus Hylastes

Since 1968 a water-based formulation of gamma BHC (Gammacol)has largely replaced DDT as a plant-dipping treatment againstthe large pine weevil Hylobius abietis L. and Hylastes spp.beetles. With Sitka spruce in high rainfall areas, BHC at 1•6 percent is as effective as DDT at 2•5 per cent in controllingthese insects. Neither chemical has proved adequate where exceptionallyhigh populations of Hylobius occurred, though control of Hylasteshas been very good. Plants were dipped in Gammacol, and then stored in sealed polythenebags for 28 days. Provided that the plants were dried sufficientlybefore storing, they subsequently suffered only a slight reductionin height-growth but received adequate protection against beetles.This technique should enable forest nurseries to supply ready-treatedplanting stock. Chlorpyrifos (Dureban) may prove a useful alternativeto BHC.     

Blue stain fungi associated withTomicus piniperda (Coleoptera: Scolytidae) on Japanese red pine

A number of various species of blue-stain fungi were isolated fromTomicus piniperda adults at various stages of development, as well as from the galleries, pupal chambers and sapwood underneath galleries on Japanese red pine. This study was an attempt to identify the species, composition of blue-stain fungi associated withT. piniperda, the frequency of occurrence of the fungi, and their role in the sapwood-staining of Japanese red pine in Tsukuba City, central Japan. Among the seven species of blue-stain fungi isolated, an undescribed species ofOphiostoma together withO. minus were the dominant species and closely associated withT. piniperda. These two species occurred on newly emerging adults more frequently than the overwintered adults.Hormonema dematioides was also associated with the beetle, however, its frequency of occurrence from the emerged new adults was very low. Although the two other species,O. ips andGraphium sp. were also isolated from emerged beetles, the frequency of these fungi from gallery systems suggested that they were accidentally carried byT. piniperda. Leptographium wingfieldii, known to be associated with the beetle in Europe, was also isolated at a very low frequency and the fungus seemed not to be closely associated with the beetle.Ophiostoma sp. andO. minus appear to be the most important causes of blue-stain of Japanese red pine sapwood after infestation byT. piniperda.     

Über die Variabilität der Brutbilder von Kiefernborkenkäfern (Coleoptera,Ipidae)

Summary Studies on the variability of galleries of pine bark beetles (Col., Ipidae) The variability of the galleries of bark beetles haven't been considered enough till now. Examples of anomalies are given and reduced to their causes. The great pine bast beetle,Myelophilus piniperda, builds the mother-gallery under the bark of stumps downwards instead of above. This can be fed back to the conditions of humidity in the stumps. The little pine bast beetle,Myelophilus minor, when attacking lying stems, often lays eggs only into the higher part of the gallery which is kept free from bore meal. Under the influence of different environment factors also other species of Hylesinini and Ipini show anomalies in building up their galleries.     

Ophiostomatoid fungi isolated from three different pine species in Argentinian Patagonia

Pine plantations in Argentinian Patagonia cover ca. 95,000 ha in Chubut, Río Negro and Neuquén provinces. Exotic bark beetles (Orthotomicus laricis, Hylastes ater and Hylurgus ligniperda) commonly occur in freshly cut logs, stumps and slash. These beetles are vectors of “ophiostomatoid” fungi which include primary tree pathogens as well as important agents of blue stain. The aim of this study was to identify these beetle‐associated fungi. Sawing mills and pine plantations were surveyed three consecutive years. Fungal isolates from stained logs, processed wood and insect galleries were identified based on morphological and DNA sequence comparisons of ITS and β‐tubulin gene regions. Two Grosmannia, one Graphilbum and three Ophiostoma species were identified. Ophiostoma piliferum and O. peregrinum sp. nov. were the most frequently isolated taxa. O. peregrinum occurred in all provinces, colonizing different conifer species and, interestingly, also the native broadleaved species Nothofagus dombeyi. Pine plantation forestry in southern South America includes Argentina, Brazil, Chile, Paraguay and Uruguay. Emerging data from Argentina, Chile and Uruguay revealed some coincidences between these countries, but also several differences, probably, as a result of multiple introduction events.     

Variation in resistance of loblolly pine (Pinus taeda L.) families against Leptographium and Grosmannia root fungi

Pine decline poses a serious threat to forest sustainability in the south‐eastern United States. Complex interactions between biotic and abiotic factors are involved in the decline and include root‐feeding bark beetles and their associated fungal genera, Leptographium and Grosmannia. A study was conducted to determine the relative tolerance of loblolly pine (Pinus taeda L.) families when challenged with either Leptographium or Grosmannia species. In the first study, bare root seedlings from 23 loblolly pine families were screened with L. procerum, L. terebrantis, G. huntii and G. alacris using an artificial inoculation method. In a second study, containerized seedlings from 27 loblolly pine families were screened with G. huntii and L. terebrantis. Measured seedling responses to the inoculations included lesion length, lesion width and occlusion of vascular tissues, measured 8 weeks after inoculations. The most common host response was dark brown lesions and resinous occluded stem tissue. Seedling families had a wide range of host responses to the different Leptographium and Grosmannia species and showed that it could be possible to select the families that may be tolerant to Leptographium and Grosmannia fungal species based on these results.     

The Influence of Soil Type and Pine Species on the Carabid Community of a Plantation Forest with a History of Pine Beauty Moth Infestation

The community composition of Carabid beetles, some species ofwhich are known predators of pine beauty moth, was examinedwithin a Scottish plantation forest. Sites differing in soiltype and the species of trees planted were sampled with pitfalltraps in most weeks of a 3—year period. There were faunaldifferences between sites with lodgepole pine on deep peat andother sites in the study (lodgepole pine on iron-pan soil, speciesmixture of lodgepole and Scots pine, and pure stands of Scotspine). In general deep peat sites supported fewer species andindividuals of carabids. Three Carabus species were implicatedas likely predators of Panolis flammea pupae and each was lessabundant on the sites with lodgepole pine. It is suggested thatthe susceptibility to pine beauty moth of lodgepole pine growingon deep peat substrates is at least partly attributable to impoverishedpredator faunas.     

The virulence of phytopathogenic fungi associated with the bark beetles Tomicus piniperda and Orthotomicus erosus in Tunisia

Phytopathogenic fungi associated with the bark beetles Tomicus piniperda and Orthotomicus erosus were isolated in various pine forests of Tunisia. Tomicus piniperda and its galleries yielded Leptographium wingfieldii, Ophiostoma minus, and Ophiostoma ips. Ophiostoma minus was the most frequent species associated with T. piniperda, in both the attacking and the emerging beetles. It was collected from most investigated forests, whereas O. ips and L. wingfieldii were obtained only from forests located in Central and Northern Tunisia. Frequencies of association with T. piniperda were always low, reaching 11.1% only once, for O. ips. Ophiostoma ips was the only blue stain fungus associated with O. erosus and its galleries. It was found in all the localities, but at a low and variable frequency, exceeding 15% very rarely. The virulence of 16 fungal isolates was tested by single inoculations into Pinus halepensis (Aleppo pine) at two localities. Differences were detected among species; L. wingfieldii was the most virulent and O. minus the least virulent species in terms of phloem reaction zone formation and fungal growth in the phloem. In a separate experiment, mass inoculations (400 and 800 inoculations per m² of bole on 1‐m high belts) were performed with two isolates of L. wingfieldii on Aleppo pine and on Pinus brutia (Brutia pine). Three months later, measurements of sapwood status (% of conductive transversal section) and of its specific hydraulic conductivity, as well as of the phloem reaction zone lengths, did not show any isolate or density effect. At these experimental sites, Brutia pines appeared significantly more susceptible than Aleppo pines.     

太原市油松小蠹虫及其综合防控技术研究

小蠹虫是一类重要的森林害虫,多为次期性害虫。通过调查,在太原市为害油松的主要种类是松六齿小蠹、松八齿小蠹和松十二齿小蠹;成虫扬飞期分别出现在5月份、7月份、8月份、9月份,是防治的关键时期;引起小蠹虫成灾的原因除自然因素外,主要是人为因素,所以防控小蠹虫要以虫情测报为基础,以检疫和林木管护措施为主导,并辅以生物、人工、化学等综合防控措施。     

An investigation of the influence of harvesting practice on the development of blue-stain in Corsican pine logs

In September 1991, at Thetford, East Anglia and at Inverness,north-east Scotland, a comparison was initiated between blue-staindevelopment in Corsican pine logs from trees felled and processedby harvesting machine and similar logs from trees felled andtrimmed out by chain-saw. Blue-stain was assessed in discs from batches of logs destructivelysampled at 2-week intervals after felling. At the more southerlysite of Thetford, stain was first observed after 4 weeks. Themaximum recorded area was 10 per cent of the wood surface ina sample analysed after 10weeks. In contrast, stain never exceeded,1.1 per cent of the wood surface at Inverness. Amounts of stainwere significantly greater with machine-harvested logs thanwith chainsaw-harvested logs and were correlated with the amountof bark removed or loosened during harvesting. The use of spikedrollers resulted in more stain than did the use of rubber rollers. The fungi isolated from stained wood included Sphaeropsis sapinea,Potebniamyces coniferarum and Ceratocystis coerulescens. Theseare species adapted to the colonization of wood exposed throughdamage to the overlying bark     

Comparative analyses of fungal biota carried by the pine shoot beetle (Tomicus piniperda L.) in northern and southern Finland

The pine shoot beetle, Tomicus piniperda, is a secondary colonizer of pines and other conifers. Although it is necessary to understand interactions of this insect with other organisms, few studies have focused on its fungal associates. This study focused on the effect of geographical distance on the occurrence of fungi carried by the beetle. Adult beetles were collected from Scots pine (Pinus sylvestris) in North (Rovaniemi) and South (Hyytiälä) Finland. The mycota was isolated and identified using a combination of morphological and molecular data. The results revealed a great diversity of fungal taxa isolated from T. piniperda, with a total of 3073 isolates representing 20 taxonomic units. The most frequently isolated fungi in the bark beetles from North Finland were Beauveria bassiana, Kuraishia sp., whereas Penicillium velutinum was mostly observed in the insects from South Finland. Ophiostoma canum and Ophiostoma minus were also isolated from the beetles from both North and South Finland. The number of fungi isolates per insect was 2.58 in the North and 3.74 in the South, respectively. Significant differences were found between South and North Finland in fungal taxa isolated from the beetles. The highest richness and diversity of the fungal taxa was observed in the South. However, the overall fungal diversity index analysis revealed that the mycobiota was under-sampled which suggests that a proportion of the fungal species may have remained undetected.     

An Analysis of Peridermium Stem Rust of Scots Pine in Thetford Forest in 1984 and 1985

The status of stem rust (Peridermium pini or (Pers.) Lev.) inScots pine (Pinus sylvestris L.) in the central block of Thetfordforest, East Anglia was determined by means of detailed analysisof freshly felled trees. A total of 935 trees was examined,these comprising c. 100 from each of nine compartments plantedbetween 1922 and 1933. Lesions in all stages of development were found; from thosein their first year of sporulation on young twigs to those whichhad been established for many years on the trunk and main branches.Death of cambium occurred typically on lesions on shoots thatwere more than five years of age. Downward growth of the funguswas estimated to average between 4.7 and 5.6 cm per year, whenbased on the length of sporulating tissue on young twigs, and6.3 cm per year when based on cambial killing in trunk lesions.The average rate of circumferential killing of trunk lesionsaveraged 4.3 crn per year (i.e. 2.2 cm in each direction). Therewas no evidence that wounds provided a significant infectioncourt. A strong association was found between the presence of the ‘purplemould’ (Tuberculina maxima) and an absence of sporulationby the rust fungus. However, there was no evidence for lesioninactivation by T. maxima. Data are presented on the distribution of disease between sitesand between trees. Five per cent of the total sample of treeswere dead and an additional 12 per cent had crown symptoms associatedwith girdling trunk lesions. Among the 775 trees with predominantlyhealthy crowns, it is estimated that 9 per cent would have diedwithin 5 years, 15 per cent within 10 years and 22 per centwithin 20 years. By contrast 66 per cent had no disease at all,probably for genetic reasons. It is concluded that, althoughthe disease situation is serious, there is no requirement fora major change to be made in the felling programme for the pre-warScots pine in Thetford.     

Effects of prescribed fire and season of burn on direct and indirect levels of tree mortality in Ponderosa and Jeffrey Pine Forests in California,USA

Many forests that historically experienced frequent low-intensity wildfires have undergone extensive alterations during the past century. Prescribed fire is now commonly used to restore these fire-adapted forest ecosystems. In this study, we examined the influence of prescribed burn season on levels of tree mortality attributed to prescribed fire effects (direct mortality) and bark beetles (Coleoptera: Curculionidae, Scolytinae) (indirect mortality) in ponderosa pine, Pinusponderosa Dougl. ex Laws., and Jeffrey pine, Pinusjeffreyi Grev. and Balf., forests in California, USA. A total of 816 trees (9.9% of all trees) died during this 3-yr study. Significantly higher levels of tree mortality (all sources) occurred following early and late season burns compared to the untreated control, but no significant difference was observed between burn treatments. The majority (461 trees) of tree deaths were attributed to direct mortality from prescribed burns and was strongly concentrated (391 trees) in the smallest diameter class (<20.2 cm diameter at breast height, dbh). For the largest trees (>50.7 cm dbh), significantly higher levels of tree mortality occurred on early season burns than the untreated control, most of which resulted from indirect mortality attributed to bark beetle attacks, specifically western pine beetle, Dendroctonus brevicomis LeConte, and mountain pine beetle, D. ponderosae Hopkins. Red turpentine beetle, D. valens LeConte, was the most common bark beetle species found colonizing trees, but tree mortality was not attributed to this species. A total of 355 trees (4.3% of all trees) were killed by bark beetles. Dendroctonus brevicomis (67 trees, 18.9%) and D. ponderosae (56 trees, 15.8%), were found colonizing P. ponderosa; and Jeffrey pine beetle, D. jeffreyi Hopkins, was found colonizing P. jeffreyi (seven trees, 2.0%). We also found pine engraver, Ips pini (Say) (137 trees, 38.6%), and, to a much lesser extent, Orthotomicus (=Ips) latidens (LeConte) (85 trees, 23.9%) and emarginate ips, I. emarginatus (LeConte) (3 trees, 0.8%) colonizing P. ponderosa and P. jeffreyi. Few meaningful differences in levels of indirect tree mortality attributed to bark beetle attack were observed between early and late season burns. The incidence of root and root collar pathogens (Leptographium and Sporothrix spp.), including species known to be vectored by bark beetles, was low (18% of trees sampled). The implications of these and other results to management of P. ponderosa and P. jeffreyi forests are discussed in detail.     

Die Wirkungsbreite des Ausstoβreflexes bei Borkenkäfernreflexes bei Borkenkäfern

Summary The thrust out-reflex of the back beetles is useful to the breeding galleries of bore-meal and other substances. The beetles also avert with this reflex other insects, who try to invade the breeding galleries. Then the bark beetle thrust out its abdomen and often that means the ruin of the beetle. The enemy — f. i.Thanasimus formicarius L. — has the opportunity to kill the bark beetle when he reaches its abdomen.     

Blue‐stain infections in roots,stems and branches of declining Pinus sylvestris trees in a dry inner alpine valley in Switzerland

Increased mortality rates in Scots pine (Pinus sylvestris) forests have recently been observed in the inner alpine Swiss Rhone valley. Drought, in combination with stand competition, mistletoe infections as well as nematode and insect infestations, appears to be the main factor for the decline. In focus of this study was the occurrence and role of fungal pathogens in the decline dynamics. Branches, stems and roots of 208 trees in five different crown transparency classes were collected and inspected for blue stain and fungal infections. Neither Armillaria species nor Heterobasidon annosum s. str. were detected, but blue stain was commonly observed. Visible blue stain increased with increasing crown transparency. Among the recently dead trees, 80% showed visible blue stain in the branches, 90% in the roots and 100% in the stems. In the crown transparency classes 2 and 3 (25–60% crown transparency), five of the 103 trees showed visible blue stain in the roots, one of 130 trees in the stem but none in the branches. Blue‐stain fungi were isolated from all parts of the trees and from all crown transparency classes. Overall incidence of blue stain was highest in the roots and lowest in the branches. In class 2, roots of 60% of the trees were visibly blue‐stained or developed blue stain in culture, but stems of only 24% and branches of 14% of the trees. In the roots Leptographium species, mostly L. serpens, dominated. From stems and branches, mainly Ophiostoma species were isolated. The positive relationship between the incidence of blue stain and crown transparency, in combination with the high infection levels of roots of fairly vigorous Scots pines, indicates the pathogenic potential of the blue‐stain fungi. Hence, these fungi together with their insect vectors may well act as an important contributing factor involved in pine decline.     

Physiological Effects of Natural and Artificial Defoliation on the Growth of Young Crops of Lodgepole Pine

Field experiments involving naturally occurring population levelsof larval European pine sawfly Neodiprion sertifer (Geoff. )and artificial defoliation in both field and glasshouse experimentswere used to investigate physiological effects of defoliationon lodgepole pine. Reductions in total projected leaf area,annual height and volume increments of 19, 33 and 32 per cent,respectively, were recorded on trees where larvae had consumedall mature foliage. Leader growth was up to 48 per cent lesson defoliated trees after two years reflecting a delayed growthimpact. Similar effects were found on trees which had been defoliatedby hand in a manner resembling sawfly feeding. Artificial defoliationof transplants also showed that this type of damage can haveserious consequences on below-ground growth, particularly offine roots. Root:shoot ratios were found to be 0.64 in undamagedplants and 1. 05 in defoliated plants. A high concentration(1300 ppm) of the insecticide fenitrothion, used to maintaincontrol treatments in the field, was found to have no significanteffects on the major growth parameters being assessed.     

A comparison of heat pulse velocity and lesion lengths for assessing the relative virulence of mountain pine beetle‐associated fungi on jack pine

The mountain pine beetle (MPB) vectors three blue‐stain fungi, Grosmannia clavigera, Ophiostoma montium and Leptographium longiclavatum, which contribute to the success of the beetles and the death of the trees. The utility of two methods, heat pulse velocity (HPV) and lesion length, for assessing the relative virulence of these fungi were compared on jack pine in central Alberta. The HPV monitoring apparatus failed to detect xylem sap flow in any of the trees and, thus, could not be used to assess fungal virulence. In contrast, measurement of lesion lengths was more sensitive and provided further evidence that G. clavigera and L. longiclavatum are more virulent than O. montium. The failure of the HPV apparatus to detect sap flow suggests that the study trees were moisture stressed, a factor likely to increase their susceptibility to MPB. Thus, this method is not appropriate for assessing the response of the most susceptible (i.e. drought stressed) trees to MPB and its associated fungi.