Usefulness of Venous Blood in Estimating Acid-Base Status of the Seriously III Dog

The usefulness of venous blood in determining the acid-base status of seriously ill animals has not been investigated. The purpose of this study was to determine whether a useful relationship exists between the acid-base parameters of central venous and arterial blood in ill dogs.
Paired arterial and venous blood samples were obtained from 46 dogs seen in the Critical Care Unit of the Veterinary Teaching Hospital of Colorado State University irregardless of their hemodynamic status. Cardiopulmonary arrest patients were not included in the study.
Results of this study indicate venous blood samples can be used in the assessment of acid-base status. Statistical significance was seen in comparing arterial versus venous pH (P < 0.001), PCO2 (P < 0.001), and bicarbonate (P < 0.001). Linear regression equations will allow one to predict arterial values from venous samples.     

Diseases of eucalypts in the central and northern provinces of Mozambique

In the mid-1970s, Mozambique embarked on several forestry projects to promote and establish large plantation areas with eucalypt trees. The planted species included Corymbia citriodora, Eucalyptus camaldulensis, E. saligna and E. tereticornis. Similar to other regions of the world, pests and pathogens pose a significant threat to eucalypt plantations in Mozambique, but little is known regarding the diseases of trees in the country. The aim of this study was to provide the first detailed consideration of the possible disease problems affecting plantation- grown eucalypt species in the central and northern provinces of Mozambique. Isolates of fungal pathogens were obtained from material displaying disease symptoms collected during two field surveys conducted in 2010 and 2011. Representative fungal isolates were identified using DNA sequence data. Stem canker diseases caused by fungi in the Botryosphaeriaceae, Cryphonectriaceae and Teratosphaeriaceae, as well as leaf spots caused by species of Calonectria, Pilidiella, Pilidium and Phakopsora myrtacearum were commonly encountered. Their relative importance to the future of planation forestry in Mozambique is discussed.     

Pathogenicity of Ceratocystis resinifera to Norway spruce

The blue‐stain fungus Ceratocystis resinifera colonizes wounds on living Picea spp. and other conifers in Europe and North America. Little is known regarding the pathogenicity of this fungus and consequently, four Norwegian C. resinifera isolates were inoculated on to Norway spruce (Picea abies) using two different techniques. These included single‐point inoculations on young trees (two inoculations per tree on 14‐year‐old trees) and mass‐inoculations on older trees (～200 inoculations per tree on 34‐year‐old trees). In both experiments, C. resinifera induced minor symptoms that in most cases did not differ significantly from inoculation with sterile agar. The virulent blue‐stain fungus C. polonica, which was inoculated for comparative purposes, induced extensive symptoms, causing 83% dead cambium circumference and 82% blue‐stained sapwood, and long necrotic lesions in the phloem. The results suggest that C. resinifera is non‐pathogenic or only mildly pathogenic to Norway spruce and does not present a threat to these trees.     

Shot hole disease on Prunus laurocerasus caused by Neofusicoccum parvum in Serbia

Between 2010 and 2014, symptoms of a shot hole disease were observed on cherry laurel (Prunus laurocerasus L.) trees and shrubs in parks and other public plantings in Belgrade, Serbia. Ten symptomatic leaves were collected from each of the diseased plants and the associated fungus isolated and identified using multigene phylogenetic analyses and asexual morphological characters. The pathogen was identified as Neofusicoccum parvum. The same symptoms were produced when the pathogen was inoculated on test plants. To the best of our knowledge, this is the first report of N. parvum causing shot hole disease on P. laurocerasus.     

Diversity and pathogenicity of Botryosphaeriaceae on declining Ostrya carpinifolia in Slovenia and Italy following extreme weather conditions

Unusual and extensive dieback of European hop hornbeam (Ostrya carpinifolia) has been observed in western Slovenia and northern Italy in recent years, when extreme drought and higher temperatures were recorded. A preliminary study identified Botryosphaeria dothidea as a potential causative agent of the dieback. Further characterization of intra- and interspecies diversity of Botryosphaeriaceae collected from O. carpinifolia and other tree species in the affected area was achieved based on anamorph morphology, sequence data from the ITS rDNA and EF1-??, PCR?CRFLP analysis and AFLP profiles. The majority of the isolates analyzed were identified as B. dothidea, and in vitro pathogenicity tests re-confirmed the fungus to be an important cause of the disease. Insight into the B. dothidea population, diversity based on AFLP markers indicates that the dieback observed in O. carpinifolia is probably associated with a heterogenous population of B. dothidea, which emerged from a latent state in response to changed climate conditions. Isolates with Dothiorella-like conidia were also identified during the survey, but these were collected more rarely and appear to represent undescribed species. Isolates from Dothiorella genus expressed low pathogenicity in pathogenicity tests and proved no impact on the pathogenic ability of B. dothidea.     

Diseases and insect pests of Gmelina arborea: real threats and real opportunities

Gmelina arborea Roxb. (gmelina) is a rapidly growing tree, which due to its drought tolerance and excellent wood properties, is emerging as an important plantation species. Perhaps the greatest threat to plantations of this tree is damage due to pests and diseases. Numerous insect pests and pathogens have been recorded in stands of gmelina in areas where the trees are native. Some fungal pathogens have been introduced into areas where the trees have been established as exotics. Among these, leaf spot caused by Pseudocercospora ranjita is most widespread although it has not caused any substantial damage. A serious vascular wilt disease caused by Ceratocystis fimbriata in Brazil has caused the most significant failure of G. arborea in plantations. In plantations within the natural range of the tree, insects have caused substantial damage. Among these, the defoliator Calopepla leayana (Chrysomelidae) appears to be most important. No serious insect pest problems have been recorded where G. arborea is grown as an exotic. All indications are that pathogens and insect pests will become much more serious impediments to the propagation of gmelina in the future. However, excellent opportunities exist to resolve such problems through biological control of insects and integrated disease and pest management. In addition, gmelina can be vegetatively propagated and thus, breeding and selection for insect and pathogen tolerance will facilitate the propagation of healthy trees. Palabras clave: Control biológico, Cuarentena, Especies exóticas, Implementación operacional de clones Resumen. La Gmelina arborea Roxb. (gmelina) es un árbol de rápido crecimiento, el cual debido a su tolerancia a las sequías y a sus excelentes propiedades de la madera se está convirtiendo en una especie de importancia para las plantaciones forestales. Tal vez, la amenaza más grande para las plantaciones de estos árboles es el daño causado por las plagas y las enfermedades. En las áreas en donde la especie es nativa, se han reportado gran cantidad de plagas de insectos y de patógenos. Algunos hongos patógenos se han introducido dentro de las áreas en donde los árboles han sido establecidos como especies exóticas. Entre estos, las manchas de las hojas ocasionadas por el hongo Pseudocercospora ranjita, es el más extendido aunque no ha causado ningún daño sustancial. Una seria enfermedad de marchitamiento vascular causada por el Ceratocystis fimbriata en el Brasil, ha causado la pérdida más seria en las plantaciones de G. arborea. En las plantaciones dentro del rango natural del árbol, los insectos han causado un daño considerable. Entre estos insectos, el defoliador más importante parece ser el Calopepla leayana (Chrysomelidae). En las áreas en donde la gmelina crece como una especie exótica no se han reportado problemas con las plagas de insectos. Todo parece indicar que en un futuro, los agentes patógenos y las plagas de insectos se convertirán en un impedimento más serio para la progagación de la gmelina. Sin embargo, a través del control biológico de insectos y del manejo integrado de las enfermedades y plagas, existen excelentes oportunidades para resolver este tipo de problemas. Además, la gmelina puede ser propagada vegetativamente y por lo tanto su mejoramiento y selección facilitará la propagación de árboles saludables por su resistenciacia contra los insectos y los patógenos.     

A new Leptographium species from the roots of declining Pinus sylvestris in Switzerland

Scots pine (Pinus sylvestris) trees have been declining in the Rhône valley, Switzerland, for almost three decades. In an assessment of the role of fungi in this syndrome, the dominant fungus isolated from stained roots was a Leptographium species, morphologically similar to the asexual state of Grosmannia serpens. We examined isolates of this fungus based on DNA sequences of four protein‐coding genes including actin, β‐tubulin, calmodulin and translation elongation factor‐1 alpha. The results showed that they were of a distinct, undescribed taxon related to species in the Grosmannia serpens and G. wageneri complexes. The fungus, described here as Leptographium rhodanense sp. nov., resembles other species in the two species complexes morphologically, and most probably ecologically, as is suggested by the fact that it was isolated from stained pine roots.     

Dissimilar stem and leaf hydraulic traits suggest varying drought tolerance among co-occurring Eucalyptus grandis × E. urophylla clones

In South Africa, there is currently a phenomenon where a Eucalyptus grandis × E. urophylla clone is dying on a large scale, whereas co-occurring clones in the same plantation area remain healthy. No primary biotic pathogen has been isolated from these dying trees. However, the plantation region has endured severe drought conditions. We hypothesised that the specific E. grandis × E. urophylla clone dieback is due in part to the affected trees having an elevated drought vulnerability. We tested this hypothesis retrospectively by examining how the dying (branch dieback started) as compared with two healthy and co-occurring E. grandis × E. urophylla clones vary in branch xylem anatomy (water transport) and leaf stable carbon isotopes (gas exchange) across two levels of mean annual precipitation in the planted landscape. There was significant intra-hybrid variation in the range of studied hydraulic traits. It appeared that the dying clone is maladapted to drier field conditions relative to the two healthy growing clones. Individuals of the drought-susceptible clone had increased hydraulic conductivity, having both wider vessel lumens and larger lumen fractions, and also did not regulate leaf-level transpiration in the drier landscape as efficiently as the two unaffected clones (lower δ¹³C ratios). In turn, one of the healthy growing clones had a completely different hydraulic strategy, having higher wood density, lower lumen fractions, and higher δ¹³C ratios that are widely considered as hydraulically resilient during water stress. The other clone appeared to also gain drought tolerance via higher leaf-level water-use efficiency, although drought tolerance was less clear regarding xylem anatomy. We highlight how variation in relative drought vulnerability can be highly significant even between clones within a single hybrid group. Knowledge of this variation in plant hydraulics between commercially planted and closely related Eucalyptus trees would complement clone deployment programmes in a target landscape.     

Factors influencing infection of Acacia mearnsii by the wilt pathogen Ceratocystis albifundus in South Africa

It is well known that species of Ceratocystis, which cause canker and wilt diseases on trees, require wounds for infection. In this regard, a number of physical and environmental factors influence the success of wound colonization by these fungi. The aim of this study was to consider the influence of wound age, stem diameter and colonization of wounds by Ophiostoma quercus on the success of infection by Ceratocystis albifundus, an important wilt pathogen of Acacia mearnsii in southern and eastern Africa, under field conditions. This was performed by doing controlled inoculations on Acacia mearnsii trees, of different diameters, with C. albifundus at different time intervals after wounding and after pre‐inoculation of wounds with O. quercus at the time of wounding. The success of infection by C. albifundus decreased significantly from 8 h after wounding and was higher on stems of greater diameter. Pre‐infection of wounds by O. quercus reduced the infection success of C. albifundus. The overall results showed that managing wounds created during forestry operations by treating wounds with naturally occurring, non‐virulent fungi, such as O. quercus, could reduce the prevalence of infections by C. albifundus.     

The tolerance of Pinus patula × Pinus tecunumanii, and other pine hybrids, to Fusarium circinatum in greenhouse trials

The field survival of Pinus patula seedlings in South Africa is frequently below acceptable standards. From numerous studies it has been determined that this is largely due to the pitch canker fungus, Fusarium circinatum. Other commercial pines, such as P. elliottii and P. taeda, show good tolerance to this pathogen and better survival, but have inferior wood properties and do not grow as well as P. patula on many sites in the summer rainfall regions of South Africa. There is, thus, an urgent need to improve the tolerance of P. patula to F. circinatum. Operational experience indicates that when P. patula is hybridized with tolerant species, such as P. tecunumanii and P. oocarpa, survival is greatly improved on the warmer sites of South Africa. Field studies on young trees suggest that this is due to the improved tolerance of these hybrids to F. circinatum. In order to test the tolerance of a number of pine hybrids, the pure species representing the hybrid parents, as well as individual families of P. patula × P. tecunumanii, a series of greenhouse screening trials were conducted during 2008 and 2009. The results indicated that species range in tolerance and hybrids, between P. patula and these species, are intermediate in tolerance to F. circinatum. Within P. patula × P. tecunumanii, large family variation exists when pollen from the high elevation source of P. tecunumanii is used. The results of these studies illustrate the importance of developing pine hybrid breeding programs to overcome the susceptibility of our pure species to pathogens such as F. circinatum.