751 research outputs found
Calonectria species associated with cutting rot of Eucalyptus
No full textDecline in the productivity of Eucalyptus hybrid cutting production in the Guangdong Province of China is linked to cutting rot associated with several Calonectria spp. The aim of this study was to identify these fungi using morphological and DNA sequence comparisons. Two previously undescribed Calonectria spp., Ca. pseudoreteaudii sp. nov. and Ca. cerciana sp. nov. were identified together with Ca. pauciramosa. Calonectria pseudoreteaudii resides in the Ca. reteaudii complex and Ca. cerciana is closely related to Ca. morganii. Connected to the discovery of Ca. pseudoreteaudii, species in the Ca. reteaudii complex were re-considered and the group is shown to accommodate two cryptic species. These originate from Australia and are described as Ca. queenslandica sp. nov. and Ca. terrae-reginae sp. nov
Brown rot a cause of blossom-blight and fruit-rot
No full textTitle from PDF cover (viewed on October 25, 2017).This archived document is maintained by the State Library of Oregon as part of the Oregon Documents Depository Program. It is for informational purposes and may not be suitable for legal purposes.Mode of access: Internet from the Oregon Government Publications Collection.Text in English
Bulletin No. 244 - Bacterial Ring-Rot of Potatoes
No full textBulletin No. 244 - Bacterial Ring-Rot of Potatoe
Bulletin No. 270 - Potato Ring-Rot and Its Control
No full textBulletin No. 270 - Potato Ring-Rot and Its Contro
Multigene phylogeny and mating tests reveal three cryptic species related to Calonectria pauciramosa
No full textCalonectria pauciramosa is a pathogen of numerous plant hosts worldwide. Recent studies have indicated that it included cryptic species, some of which are identified in this study. Isolates from various geographical origins were collected and compared based on morphology, DNA sequence data of the ß-tubulin, histone H3 and translation elongation factor-1 regions and mating compatibility. Comparisons of the DNA sequence data and mating compatibility revealed three new species. These included Ca. colombiana sp. nov. from Colombia, Ca. polizzii sp. nov. from Italy and Ca. zuluensis sp. nov. from South Africa, all of which had distinguishing morphological features. Based on DNA sequence data, Ca. brasiliensis is also elevated to species leve
Tailoring mechanical properties of randomly oriented tape (ROT) composites: An experimental study
No full textDiscontinuous fiber composites (DFC) have properties such as notch insensitivity, short processing times, and large shaping freedom [1-3]. However, the mechanical behavior of ROT composites is less predictable compared to continuous fiber composites due to the mesoscopic heterogeneity of the material [4]. Controlling the tape alignment is a compelling approach for tailoring the mechanical properties of the ROT composites, enabling better control and prediction of the material properties such as tensile strength and stiffness [5]. However, for a successful implementation of the alignment method in industry, a fast tape alignment method is needed. In this study, a quantitative assessment has been made between three alignment methods. The methods have been evaluated in respect of the level of alignment and the manufacturing process by means of a decision-making matrix. The level of alignment of each method has been determined using computer vision on the orientation of individual tapes. The final alignment method has been selected which uses vertical mesoscopic sieves with a high aspect ratio to rotate tapes in a preferred direction during deposition. With this alignment method, ROT have been aligned at -45˚, 0˚, and +45˚ with respect to the loading direction. With these alignment tools, CF/PEEK ROT have been deposited inside a cavity followed by a consolidation cycle at 45 bar and 385˚C. The effect of alignment was examined by comparing the mechanical response of samples with: ROT, being longitudinally aligned, and a laminate of [+45˚,-45˚]s aligned pseudo-layers. The results of tensile tests showed that by aligning tapes in the longitudinal direction, the average tensile stiffness and strength increased by 145% (from 32.5 to 79.7 GPa) and 96% (from 202 to 396 MPa) respectively compared to randomly orientated tapes. These results show the potential gain in material properties and the ease of implementation of the method.Aerospace Manufacturing Technologie
A Survey of Heart Rot in Some Plantations of Acacia mangium Willd. In Sabah.
No full textOnly 4% of thinnings had heart rot which appeared to originate from thinning wounds. In the older trees, the average incidence of heart rot was 35.5%. -from Author
Phylogenetic lineages in the Botryosphaeriaceae
No full textBotryosphaeria is a species-rich genus with a cosmopolitan distribution, commonly associated with dieback and cankers of woody plants. As many as 18 anamorph genera have been associated with Botryosphaeria, most of which have been reduced to synonymy under Diplodia (conidia mostly ovoid, pigmented, thick-walled), or Fusicoccum (conidia mostly fusoid, hyaline, thin-walled). However, there are numerous conidial anamorphs having morphological characteristics intermediate between Diplodia and Fusicoccum, and there are several records of species outside the Botryosphaeriaceae that have anamorphs apparently typical of Botryosphaeria s.str. Recent studies have also linked Botryosphaeria to species with pigmented, septate ascospores, and Dothiorella anamorphs, or Fusicoccum anamorphs with Dichomera synanamorphs. The aim of this study was to employ DNA sequence data of the 28S rDNA to resolve apparent lineages within the Botryosphaeriaceae. From these data, 12 clades are recognised. Two of these lineages clustered outside the Botryosphaeriaceae, namely Diplodia-like anamorphs occurring on maize, which are best accommodated in Stenocarpella (Diaporthales), as well as an unresolved clade including species of Camarosporium/Microdiplodia. We recognise 10 lineages within the Botryosphaeriaceae, including an unresolved clade (Diplodia/Lasiodiplodia/ Tiarosporella), Botryosphaeria s.str. (Fusicoccum anamorphs), Macrophomina, Neoscytalidium gen. nov., Dothidotthia (Dothiorella anamorphs), Neofusicoccum gen. nov. (Botryosphaeria-like teleomorphs, Diapjomera-like synanamorphs), Pseudofusicoccum gen. nov., Saccharata (Fusicoccum- and Diplodia-like synanamorphs), "Botryosphaeria" quercuum (Diplodia-like anamorph), and Guignardia (Phyllosticta anamorphs). Separate teleomorph and anamorph names are not provided for newly introduced genera, even where both morphs are known. The taxonomy of some clades and isolates (e.g. B. mamane) remains unresolved due to the absence of ex-type cultures
Two new Phytophthora species from South African Eucalyptus plantations
No full textA recent study to determine the cause of collar and root rot disease outbreaks of cold tolerant Eucalyptus species in South Africa resulted in the isolation of two putative new Phytophthora species. Based on phylogenetic comparisons using the ITS and β-tubulin gene regions, these species were shown to be distinct from known species. These differences were also supported by robust morphological characteristics. The names, Phytophthora frigida sp. nov. and Phytophthora alticola sp. nov. are thus provided for these taxa, which are phylogenetically closely related to species within the ITS clade 2 (P. citricola, P. tropicali and P.multivesiculata) and 4 (P. arecae and P. megakarya), respectively. Phytophthora frigida is heterothallic, and produces stellate to rosaceous growth patterns on growth medium, corraloid hyphae, sporangia with a variety of distorted shapes and has the ability to grow at low temperatures. Phytophthora alticola is homothallic and has a slower growth rate in culture. Both P. frigida and P. alticola are pathogenic to Eucalyptus dunnii. In pathogenicity tests, they were, however, less pathogenic than P. cinnamomi, which is a well-known pathogen of Eucalyptus in South Africa
Mushroom root rot of fruits caused by Armillaria mellea
No full textTitle from PDF caption (viewed on November 14, 2017).This archived document is maintained by the State Library of Oregon as part of the Oregon Documents Depository Program. It is for informational purposes and may not be suitable for legal purposes.Mode of access: Internet from the Oregon Government Publications Collection.Text in English
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