Gallery Formation Research Articles

Acibenzolar-S-methyl induces resistance against ambrosia beetle attacks in dogwoods exposed to simulated flood stress.

Xylosandrus spp. ambrosia beetles (Coleoptera: Curculionidae: Scolytinae) are important wood-boring pests of nursery trees weakened by abiotic and biotic stressors. Acibenzolar-S-methyl (ASM), a plant defense elicitor, was tested for inhibiting Xylosandrus spp. tunneling (i.e., attacks) into flood-stressed flowering dogwoods (Cornus florida L. (Cornales: Cornaceae)). Container-grown dogwoods were treated with ASM substrate drench + flooding, ASM foliar spray + flooding, ASM drench + no flooding, ASM foliar + no flooding, no ASM + flooding, or no ASM + no flooding at 3 days before flood stress in a completely randomized design under field conditions. Trees were flooded for 14 days and then drained and watered as needed. Attacks were counted every 2 days for 28 days. Plant tissue samples were collected at 7 and 14 days after flooding to determine ethanol content using solid-phase microextraction-gas chromatography-mass spectrometry. Trees were dissected to determine gallery formation and depth, fungal colonization, and the presence of eggs, larvae, and adults. The highest number of Xylosandrus beetle species attacks were recorded from plants exposed to no ASM + flooding, but attacks were reduced in ASM treated trees (drench or foliar) + flooding. Trees treated with drenches had fewer attacks than foliar sprays. Plants assigned to no flood had the fewest beetle attacks. Moreover, ASM reduced Xylosandrus spp. gallery formation and depth, fungal colonization, and presence of eggs, larvae, and adults. All flooded trees produced ethanol. In conclusion, ASM induced a plant defense response to Xylosandrus spp. tunneling in dogwoods under flood stress conditions.

Efficacy of some entomopathogenic fungi against tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae)

BackgroundEffects of entomopathogenic fungi (EPF); Beauveria bassiana, Isaria fumosorosea and Pupureocillium lilacinum against tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), which is one of the most economic pests of tomato, were investigated in Petri dish, pot and greenhouse experiments. Commercial bioinsecticide Met 52 was also used in the experiments. In the Petri dish trials, I. fumosorosea applied to the third instar larvae by dipping method was recorded as the most effective entomopathogen, while the efficacy of B. bassiana was high in the spray and residue methods. In the pot experiments, entomopathogenic fungi were applied to tomato plants before and after infestation with T. absoluta.ResultsAs a result of the applications, it was found that the EPF significantly reduced the formation of galleries on tomato leaves when applied before or at the beginning of tomato leafminer infestation. In the greenhouse experiments a registered insecticide Voliam Targo was also applied. All applications significantly reduced the numbers of galleries on tomato leaves than in the control plants, in both greenhouse trials, made in Antalya and Isparta Provinces. I. fumosorosea was the most effective one among the tested 3 EPF.ConclusionsIn this study, it was determined that the EPF B. bassiana and P. lilacinum can reduce tomato leafminer damage, while the efficacy of I. fumosorosea was the highest, and especially after two applications it was nearly effective as the registered insecticide.

Integration of Control Strategies to Optimize Management of Ambrosia Beetles (Coleoptera: Curculionidae, Scolytinae) and Phytophthora Root Rot (Peronosporales: Peronosporaceae) in Flowering Dogwoods (Cornalaes: Cornaceae) After Simulated Flooding.

Ambrosia beetles (Coleoptera: Curculionidae, Scolytinae) and Phytophthora root rot (Peronosporales: Peronosporaceae) cause significant damage to the ornamental industry in the United States. In this study, mefenoxam (fungicide), permethrin (insecticide), and charcoal + kaolin were used in different combinations with Phytophthora cinnamomi (Rands: Peronosporales: Peronosporaceae) inoculated and noninoculated plants to optimize the management of ambrosia beetles and Phytophthora root rot. Treatment applications were performed in two trials on 1 (mefenoxam, drench), 18 (P. cinnamomi inoculation), or 19 (permethrin, spray) days before instigating flood stress or 2 d after flood stress (charcoal + kaolin, spray), respectively. Flooding was maintained for 21 d. Ambrosia beetle attacks and plant growth data were recorded. Tree roots were rated at study end for disease severity and root samples were plated on PARPH-V8 medium to determine the percentage of pathogen recovery. In both trials, the combination of mefenoxam + permethrin treatment had reduced disease severity and ambrosia beetle attacks compared to the inoculated controls. Permethrin-treated trees had shorter galleries compared to controls in trial 1 and no gallery formation in trial 2. In both trials, no differences were observed among the treatments in numbers of galleries with eggs and adults, but mefenoxam + charcoal + kaolin had significantly fewer galleries with larvae among the noninoculated trees compared with the respective control in trial 1. Overall, treatments containing combinations of mefenoxam + permethrin had reduced disease severity and ambrosia beetle attacks.

Local Government and Community Efforts in the Development of Kalaodi Agrotourism, Tidore Archipelago City, Indonesia

This research aimed to examine the development of Kalaodi Agrotourism, the development of tourism facilities in the Kalaodi Agrotourism area, and the development of human resources in the tourism sector carried out by local governments and communities. This research used a qualitative descriptive approach, and it used an interactive model as the data analysis technique. The results showed that Kalaodi had many kinds of tourism wealth, specifically, in the form of nature, agro, and cultural tourism. The Kalaodi community had the will and enthusiasm to develop tourism objects in their area. There were various public transportation facilities such as roads, good sanitation, electricity facilities, and communication facilities even though Kalaodi was a village located far from the central government and urban areas. In addition, the Kalaodi community had developed human resource development programs, such as the creation of literacy houses, the formation of art galleries, English language training, and home industry product development training. In developing agrotourism, the collaboration between the local government and the community is needed, both in the development of tourist objects and tourism support facilities. Keywords: Development, Kalaodi Agrotourism, Tidore

Coal Pillar Extraction Under Weak Roof

This article offers an examination of a retreat mining method conducted at the Pinoura Mine in India from 2010 to 2017. The method is atypical for coal mines of India’s coalfields. The method executes depillaring in a single pass and does not require the formation of galleries and support installation in splits, thus, reducing the cycle time. A variety of observations are discussed throughout this work and emphasis is placed on field measurements and depillaring under weak roof (RMR = 40–45). This paper discusses design techniques, specifically the estimation of the snook (remnant pillar) size, and important practical observations after the fact. The execution of this method was eventually conducted in eleven panels.

Pseudodifferential adiabatic mode parabolic equations in curvilinear coordinates and their numerical solution

Pseudodifferential mode parabolic equations in curvilinear coordinates are derived from the horizontal refraction equations. An energy-conserving split-step Padé method for their numerical solution is developed. Several examples are considered including the propagation of sound in a perfect wedge, a whispering gallery formation near circular isobath, and the breaking of the whispering gallery waveguide in the vicinity of an inflection point of the isobath.

Landforms Evolution of Wadi Qudaid Area, West Central Arabian Shield, Saudi Arabia: An Example of the Role of the Geological Factors in the Urban Extensions

Wadi Qudaid is located in the west central part of Saudi Arabia. It about 135 km to the northeast of Jeddah city along Al Haramein highway and it represents the upstream of the very large alluvial plain along the Red Sea coast. It runs in NE direction parallel to many wadis of the west central part of Saudi Arabia i.e. Wadi Fatima, wadi Sitarah. The wadi floor is filled by Quaternary deposits which represent good groundwater aquifer. Geologically, the present-day residual landforms of Wadi Qudaid are composed mainly of Precambrian Arabia shield rocks overlained by Tertiary sedimentary rocks and finally harrat (Tertiary volcanic). The Precambrian rocks are represented by 1) a lower layered basic and intermediate volcanic and the intercalated volcaniclastics. This unit is correlatable with Samran Group, 2) an upper layered acidic volcanic and the intercalated acidic volcaniclastics. The Arabian shield rocks are intensively folded and dragged along the major NE faults. They are directly overlain by Tertiary basic volcanic (harrat) and the related volcanoclastic red beds). The main geomorphologic elements of the study area include plateau, scarps, and the wadi floor. The plateau is represented by the black basaltic sheet that contains some semi-rounded depressions filled with Quaternary eolian sands. The scarps of the main wadi and its tributaries are nearly steep and contain many asphaltic roads with some isolated cone hills detached from the scarps. Geomorphological, Wadi Qudaid represents the incomplete erosion cycle that begins with the formation of deep galleries and very steep and narrow wadies formed along the major NE faults and related fractures and folds. The progress of the erosion processes led to the formation of narrow interfluves as a result of pedimentation and sculpturing of the wadies sides by scarp retreat. The peniplanation stages of the erosion cycles are reached in the southwestern and the central part of the wadi where fast peniplained areas were formed. The results of this study revealed the role of the different geological processes (lithology, structural elements and climatic conditions) in the distribution of present-day human populations in urban extensions. Qudaid, Dhubaya-Jumah, Dabyah, Al Khamrah, Almansa and Al Massamah are the main villages of Wadi Qudaid area.

Xyleborus volvulus (Coleoptera: Curculionidae): Biology and Fungal Associates.

The ambrosia beetle Xyleborus volvulus Fabricius has been reported as a potential vector of the plant pathogen Raffaelea lauricola T.C. Harr., Fraedrich & Aghayeva that is affecting avocado orchards in South Florida. In this study, we examined its life cycle, process of gallery formation, gallery structure, and fungal associates by rearing one generation on avocado sawdust medium under control conditions. The adult foundress excavated a vertical tunnel that constituted the main gallery with a length of 2.5 cm, followed by the construction of up to six secondary galleries with a total length of 4.4 cm. The time period for one generation (egg to adult) was 28 days. Teneral males emerged 3 days after the emergence of the first females. The F1 generation did not significantly contribute to gallery expansion. Four species of Raffaelea and nine yeast species were recovered from galleries and beetles. Raffaelea arxii and Candida berthetii were the most frequent symbionts recovered from new adults and galleries. Candida berthetii dominated during the early stages of the gallery development, whereas R. arxii was most frequent in later stages. Other Raffaelea species were inconsistently isolated from galleries, which suggests a strong association between Xyleborus volvulus and both R. arxii and C. berthetii These results suggest that R. arxii is the primary nutritional symbiont of X. volvulus and that yeast species may be pioneer colonizers that assist with the growth of fungal symbionts.IMPORTANCE Ambrosia beetles cultivate fungi in tunnels bored into weakened host trees. This obligate interaction is required for their survival as beetles feed on these symbiotic fungi, and the fungi benefit from transportation by the beetles. Xyleborus volvulus carries many nonpathogenic symbionts; however, recently the acquisition of Raffaelea lauricola (the causal agent of a lethal vascular disease of lauraceous trees) by this beetle has altered its status from wood degrader to potential pest in avocado. We conducted a study to understand the relationship of this beetle and its fungal associates. Our results show that X. volvulus has a multipartite flexible association with different Raffaelea species. The lack of fidelity in the mutualistic association may explain the acquisition of R. lauricola Knowing the beetle biology and its mutualistic interactions furthers an understanding of the beetle's role as a potential vector and in disease transmission.

Mortality and reduced brood production in walnut twig beetles, Pityophthorus juglandis (Coleoptera: Curculionidae), following exposure to commercial strains of entomopathogenic fungi Beauveria bassiana and Metarhizium brunneum

Thousand cankers disease (TCD), caused by the walnut twig beetle (WTB), Pityophthorus juglandis, and its associated fungal symbiont, Geosmithia morbida, is a disease of economic and ecological concern on eastern black walnut, Juglans nigra. Numerous attacks and gallery formation by the WTB and subsequent development of cankers caused by the fungus result in progressive crown dieback. The disease can kill affected trees in a few to several years following initial infestation and very few management options are available for preventing or reducing impact of TCD on black walnut trees. Since advanced development of TCD requires multiple WTB generations and numerous beetle attacks, control strategies that reduce beetle attacks and brood production, without completely eliminating infestation, could still significantly benefit tree health and survival. We evaluated the use of entomopathogenic fungi Beauveria bassiana and Metarhizium brunneum against the WTB. Laboratory and field studies showed that WTB adults are susceptible to commercial strains B. bassiana GHA and M. brunneum F52. Exposure of beetles to sprayed walnut bolts resulted in reduced brood production, primarily due to the death of parental adults from fungal infection prior to egg laying. Spraying walnut bolts with B. bassiana GHA and M. brunneum F52 prior to field exposure to natural WTB populations reduced emergence of next generation adults by up to 98% and 96%, respectively, due to a combination of fewer beetle attacks and mortality among those that tunneled. These results demonstrate the potential use of entomopathogenic fungi in the integrated management of TCD in walnut trees.

Cry1Ac-mediated resistance to tomato leaf miner (Tuta absoluta) in tomato

Tomato leaf miner (Tuta absoluta) is a major pest of tomato in regions with hot climates such as South America and the Mediterranean. This insect feeds on almost every part of the plant and forms galleries while feeding on the plant’s inner tissues. Thus, it can cause plant death and is costly and difficult to control with chemical sprays. In this study, we transferred a modified Bacillus thuringiensis cry1Ac gene to tomato plants via Agrobacterium tumefaciens mediated transformation. Introduction of the cry1Ac gene to the tomato genome was confirmed with PCR and Southern blot analysis in 12 independent events. Insertion sites of the transgene in the tomato genome were determined with TAIL-PCR (thermal asymmetric interlaced polymerase chain reaction) for four selected transgenic lines. Cry1Ac gene expression was verified at both the transcriptional and translational levels, with RT-qPCR and Western blot analyses, respectively. Expression of the Cry1Ac protein in tomato resulted in T. absoluta mortality rates of 38–100% depending on transgenic line. In addition, gallery formation was reduced in 57–100% of the transgenic plants. Moreover, it was found that a single copy of the gene in the hemizygous condition is sufficient to confer tolerance to leaf miner. This is the first reported development of tomato plants resistant to T. absoluta. These transgenic plants are promising for development of commercial tomato cultivars resistant to leaf miner, which will limit the use of environmentally harmful chemicals for control of this pest.

The role of Euwallacea nr. fornicatus (Coleoptera: Scolytinae) in the wilt syndrome of avocado trees in Israel

The polyphagous shot hole borer (PSHB), Euwallacea nr. fornicatus (Coleoptera; Scolytinae) has become a serious threat to the avocado industry and several shade tree species in Israel. Branch wilting and tree mortality is the outcome of PSHB galleries. Understanding the relationship between avocado trees and the PSHB is required for considering management strategies. In Israel, 52 tree species from 26 botanical families were attacked by the PSHB, but only 12 species were suitable for beetle reproduction. All examined avocado cultivars were attacked, but ‘Hass’ most severely. Large and medium diameter avocado branches were more resistant to PSHB, compared to thin branches. Effectively, gallery density increased as branch diameter decreased. Concomitantly, in large and medium diameter branches, extensive sugar exudation occurred and beetle attack rarely progressed to the formation of natal galleries, whereas minimal sugar exudation was observed in thin branches. This was more evident in those that were weakened by repeated attacks followed by successful beetle colonization. PSHB prefers and successfully colonized branches that had been previously attacked by its conspecifics, and reproduction was much higher in these branches, as opposed to initial attacks. Lesion frequencies increased from late spring (April) until late summer (September). Avocado branches at the early stages of beetle colonization may be identified by sugar exudation at the base of the thin branches. The main approach for reducing damage caused by the PSHB is sanitation, achieved by the removal of colonized branches and intact infested pruned slash.

Monitoring of parallel galleries in the region of horizontal motion of lithospheric plates

The problem of estimating the stress-strain state of underground openings of solid minerals, which form long parallel underground galleries, is considered. Several papers studied the local causes of accidents that occur in underground galleries during mineral extraction due to variations in the stress-strain state of the medium. The influence of formation of new galleries, which violate the balance of vertical stresses in the walls between the galleries, is also studied. At the same time, the problem on the influence of horizontal displacements of lithospheric plates on the stress-strain state of parallel galleries is little studied. These displacements affect the horizontal components of the contact stress vector arising between the upper and lower layers and the walls between the galleries. In this paper, the theory of estimating the stress-strain state in underground openings with arbitrarily many parallel galleries of various dimensions is developed under the assumption that the tangential components of the stress vector exist in the contact regions between the layers and the walls. The study is based on factorization methods, block element method, and a topological approach.

Differences among avocado cultivars in susceptibility to polyphagous shot hole borer (Euwallacea spec.)

AbstractPolyphagous shot hole borer (PSHB) (Euwallacea spec.; Coleoptera: Curculionidae: Scolytinae) has recently invaded southern California, USA. Along with its associated fungi, the beetle causes branch dieback and tree mortality in more than 200 host tree species, including avocado (Persea americana Mill., Lauraceae) and many important native, urban landscape, and nursery stock trees. As PSHB spreads into the avocado‐growing regions of southern California, there is a pressing need for more information for effective management of the insect/fungus complex. The objective of this study was to examine avocado cultivars to see whether there were differences in susceptibility to attack and gallery development from PSHB. We conducted choice and no‐choice trials with cut branches in the laboratory, artificially infested avocado saplings with PSHB, and also surveyed attack rates for two cultivars of field‐grown avocado subject to natural attack by PSHB. Laboratory and field trials showed similar patterns for preference among avocado cultivars indicated by beetle attack rates and gallery formation. Among the common commercial cultivars, Fuerte, Gwen, and Bacon most often had lower attack rates and lower rates of gallery formation. Zutano most frequently indicated high attack rates and much gallery formation, indicating that it may be the most susceptible to PHSB of the commercial cultivars.

Potential pesticides for control of a recently introduced ambrosia beetle (Euwallacea sp.) in southern California

Polyphagous shot hole borer (PSHB) has recently invaded southern California. This beetle attacks more than 200 host tree species, including avocado (Persea americana Mill.) and many important native, urban landscape and nursery stock trees including sycamore (Platanus racemosa Nutt.), and box elder (Acer negundo L.). The beetle, along with its associated fungi, causes branch dieback and tree mortality in a large variety of tree species. Due to the severity of the impact of PSHB, short-term management tools must include chemical control options for the industry and private landowners to protect trees. We assessed the effectiveness of systemic and contact insecticides for control of PSHB in laboratory tests using fresh-cut castor bean (Ricinus communis L.) branches. Castor bean was chosen because, as a weedy species, it is widely available, and it is a preferred host for the beetles. We conducted field tests using mature, weedy, infested field-grown castor bean. We also surveyed infested coral trees (Erythrina corallodendron L.) in an established residential landscape. For field-grown infested castor bean, beetle activity was lowest for plants treated with bifenthrin, imidacloprid and dinotefuran. Bifenthrin was the most effective insecticide for reducing beetle attacks and gallery formation in castor bean branches in laboratory experiments with cut branches. Dinotefuran was more variable in effectiveness in laboratory trials. Fenpropathrin, clothianidin and orange oil extracts did not differ from untreated controls in beetle attacks and gallery formation. Based on these results, bifenthrin and imidacloprid were selected for further testing in combination with fungicides for control of PSHB.

Life Cycle, Development, and Culture ofXyleborus glabratus(Coleoptera: Curculionidae: Scolytinae)

The redbay ambrosia beetle, Xyleborus glabratus Eichhoff (Coleoptera: Curculionidae: Scolytinae), is a wood-boring pest that transmits the fungal pathogen Raffaelea lauricola, the causal agent of laurel wilt disease in American Lauraceae. This study documents the gallery formation patterns of X. glabratus as well as its life cycle and development at 25 ± 2 °C in logs of 3 natural hosts: avocado (Persea americana), redbay (P. borbonia) and swampbay (P. palustris). Females were observed to excavate galleries perpendicular to the tree trunk; galleries were characterized by a main entrance tunnel, from which branched secondary tunnels that, in turn, gave rise to tertiary tunnels. By dissecting infested logs daily, the length of time was determined for each developmental stage, and found to be comparable in all 3 hosts. Eggs were first encountered in avocado, redbay, and swampbay at 7, 11, and 10 days after gallery initiation (agi), respectively; larvae at 14, 20, and 14 days agi; pupae at 24, 26, and 26 days agi; and teneral adults at 31, 30, and 27 days agi. Despite comparable rates of development in all hosts, there were fewer progeny per female produced in avocado. Oviposition by the founding female extended over a broad time-span, and all stages were observed in the gallery at 1 month agi. Three larval instars were present, with mean head capsule widths of 0.21, 0.26, and 0.37 mm, respectively. Long term rearing of X. glabratus was achieved on swampbay logs soaked in water prior to infestation. Emergence of new females from logs was first observed at 60 d agi, indicating that teneral adults remain in hosts for ∼1 month prior to dispersal. Emergence continued for up to 240 days, with maximum emergence observed between 120–150 days agi.

Granulate ambrosia beetle, Xylosandrus crassiusculus (Coleoptera: Curculionidae), survival and brood production following exposure to entomopathogenic and mycoparasitic fungi

The granulate ambrosia beetle, Xylosandrus crassiusculus, is one of the most important exotic pests in orchards and nurseries in the US. The beetle has a wide host range, including some of the most popular and valuable trees in nurseries, and is difficult to control using chemical insecticides because of its cryptic habits. In this study we evaluated the susceptibility of X. crassiusculus to three commercial strains of entomopathogenic fungi and also examined gallery formation and brood production among females exposed to these biocontrol agents and a mycoparasitic fungus, Trichoderma harzianum. All three entomopathogens were virulent to X. crassiusculus: Beauveria bassiana strains GHA and Naturalis and Metarhizium brunneum F52 produced 76.7±7%, 95.6±1.1%, and 78.9±7.8% mortality, respectively, among treated adult females at the highest dose (600conidia/mm2) 5days after inoculation. Females exposed to beech stems treated with entomopathogenic fungi at the highest concentration had lower survival rates and produced fewer galleries. All concentrations tested, however, resulted in females with fewer offspring compared to control. Those exposed to T. harzianum strain KRL-AG2 produced galleries with sparse, patchy, or no symbiont growth, many of which had no or few brood present. Some of the females exposed to either B. bassiana or M. brunneum also had galleries with sparse mycelial growth. These results show the potential of entomopathogenic or mycoparasitic fungi in controlling X. crassiusculus, either directly by killing adult females and preventing or reducing brood production or indirectly by suppressing growth or establishment of their fungal symbiont in galleries.

Black Walnut Mortality in Colorado Caused by the Walnut Twig Beetle and Thousand Cankers Disease

Since 2001, widespread mortality of black walnut (Juglans nigra) has been reported in Colorado, USA. Affected trees initially show a yellowing and thinning of leaves in the upper crown, followed by twig and branch dieback and ultimately tree death. We report that this mortality is the result of a combination of an expanded geographic range of the walnut twig beetle (Pityophthorus juglandis), its aggressive feeding behavior on black walnut, and extensive cankering caused by an unnamed Geosmithia fungus associated with the beetle. Geosmithia was consistently recovered from the bodies of P. juglandis and this insect introduces the fungus into healthy trees during gallery formation. This is the first report of Geosmithia as a pathogen of black walnut. We propose the name Thousand Cankers to describe this disease because mortality is the result of bark necrosis caused by an enormous number of coalescing branch and trunk cankers. A second pathogen, Fusarium solani, was isolated from the margins of elongate trunk cankers during the final stages of decline, but not from cankers surrounding beetle galleries. Thousand Cankers Disease is eliminating black walnut along the Front Range of Colorado and poses a grave risk to this species in its native range in eastern North America should the insect/Geosmithia complex be introduced. Accepted for publication 26 May 2009. Published 11 August 2009.

Evaluation of Cu-PPHs as active catalysts for the SCR process to control NO x emissions from heavy duty diesel vehicles

Copper based catalysts supported on mesoporous materials, which were in turn based on a surfactant expanded zirconium phosphate for the formation of silica galleries in the interlayer space, were prepared by the impregnation method. They were then characterised and tested in the selective catalytic reduction of NO with ammonia as active catalysts for the control of the NO x emissions from heavy duty vehicles. Copper catalysts displayed a high catalytic performance, even in the presence of 14% (v/v) of H 2O and 100 ppm of SO 2. They also displayed improved catalytic behaviour when compared to a CuZSM5 catalyst.

Evaluation of genetic variation of attack and resistance in lodgepole pine in the early stages of a mountain pine beetle outbreak

We examined variation of attack by mountain pine beetle (MPB) (Dendroctonus ponderosae) (Coleoptera: Scolytidae) in a 20-year-old lodgepole pine open-pollinated (OP) family trial composed of 165 OP parent-trees originating from local and nonlocal provenances. Trees were assessed in the summer of 2005 for traits relating to attack, survival, gallery formation, and infection from the fungi associated with MPB, Ophiostoma sp. Successful initial attack was determined by the presence of dead (i.e., red or gray foliage) crowns and the presence of entrance holes from MPB. Eighty-seven percent of the trees still had green crowns in the fall of 2005 (GC05), with family mean differences ranging from 46 to 100%. The mean number of pitch tubes per tree (PT#05) (in a sampling area of 225 cm2 at breast height) was 1.5 with a range from 0 to 14 per tree. However, for pitch tubes indicating presence or absence (PTP05) of MPB on each tree, 63% of the trees had pitch tubes and family means ranged from 7 to 100%. Significant levels of genetic variation were found for GC05 and PTP05 with narrow-sense heritabilities of 0.20 (SE = 0.11) and 0.26 (SE = 0.07), respectively. Provenance differences were also significant, indicating that some population structure is present for these “resistance” attributes. The family breeding value correlations between 10-year height growth and PTP05 was 0.22, indicating that at the population level faster growing families may be slightly more subject to attack. An intensive survey of a subsample of 442 trees in the test (selected from 50 families with a range of attack levels) was conducted, and trees were reassessed for the presence of attack, presence of blue stain in the wood, and presence of galleries and egg chambers/eggs in the gallery. Family means ranged from 0 to 57% for blue stain, 11 to 63% for galleries, and 0 to 57% for egg chambers/eggs; however, due to the relatively small sample sizes and the nature of the binary data, family differences were not highly statistically significant. Further research is underway to improve the quantitative genetic parameters and determine the actual mechanisms at work; however, it is clear the MPB does react differently to host genotypes in terms of initial attack.

Lamellar Reaction Phenomena — From Intercalation to Nanomaterials Formation

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.