Academic literature on the topic 'Trees Diseases and pests Victoria'
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Journal articles on the topic "Trees Diseases and pests Victoria"
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Bertolini, Vincenzo, Noé Manuel Montaño, Eduardo Chimal Sánchez, Lucía Varela Fregoso, Jaime Gómez Ruiz, and José Martín Martínez Vázquez. "Abundancia y riqueza de hongos micorrizógenos arbusculares en cafetales del Soconusco, Chiapas, México." Revista de Biología Tropical 66, no. 1 (December 13, 2017): 91. http://dx.doi.org/10.15517/rbt.v66i1.27946.
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In the Mexican economy, particularly in the Soconusco region of Chiapas, the cultivation of coffee generates significant inputs; however, coffee plants are susceptible to pests and diseases, so it is necessary to reinforce its production through sustainable management. In this study, we searched for the native arbuscular mycorrhizal fungi (AMF) that could be used as biofertilizers in coffee cultivation. We collected 21 soil samples coming from seven coffee plantations (Coffea canephora) in the Soconusco region Chiapas, Mexico in November 2015. We isolated the spores of AMF by the wet sieving and decanting method to quantify their abundance, richness and composition of morphospecies, as well as their relationships with soil properties. A total of 20 morphospecies and five new records of AMF were obtained, and the most frequent genera were Acaulospora and Glomus. The Toluca and Victoria sites had higher morphospecies richness (17 spp. c/u) than San Agustín, November 20 and San Luis Nexapa (4-7 spp. c/u); while Providencia and Platanar sites recorded an intermediate richness and the highest values of spore abundance. The dissimilarity of Victoria and Toluca in its composition of AMF, respect to the other sites, was explained by the low concentration of PO4-3 in the soil. P availability, linked to soil acidity, is the factor that could be regulating the AMF communities in the soil of the rhizosphere of coffee trees at Soconusco. We consider that could have consortia of AMF specific for soil P-levels and acidity of coffee sites, i.e. Acaulospora and Glomus consortia, which are common into the environmental conditions of coffee plantations in México. Anyway, we need to examin deeply these strains to evaluate their compatibility and functionality before proposing them as native biofertilizers that promote the development and yield of coffee plantations in this tropical region of Mexico.
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Luck, Joanne E., Rosa Crnov, Barbara Czerniakowski, Ian W. Smith, and Jane R. Moran. "Investigating the Presence of Biotic Agents Associated with Mundulla Yellows." Plant Disease 90, no. 4 (April 2006): 404–10. http://dx.doi.org/10.1094/pd-90-0404.
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The role of biotic agents in the dieback syndrome Mundulla Yellows (MY) was investigated by analysis of 40 Eucalyptus camaldulensis, E. leucoxylon, or E. cladocalyx trees and soil samples from South Australia and Victoria, Australia. No pathogenic fungi, bacteria, phytoplasmas, or insect pests or vectors were found to be associated with MY. However, nematode analysis identified Merlinius spp. to be associated with soil, but not roots, from symptomatic trees. Interveinal chlorosis symptoms were not transmissible by seed, mechanical inoculation, or grafting using plant material derived from symptomatic trees. Virus-like particles were detected at a single symptomatic study site using transmission electron microscopy. MY symptoms were induced in E. camaldulensis seedlings by sowing seed from asymptomatic trees into sterilized and unsterilized soil collected from underneath symptomatic trees. Significantly, sterilized soil induced more severe symptoms in seedlings than unsterilized soil. Soil collected from under asymptomatic trees did not induce MY symptoms. This preliminary investigation indicates that, with the exception of Merlinius spp., pathogenic organisms and pests were not consistently associated with MY symptoms.
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Gonda, István, Imre Holb, and Klára Bitskey. "Previous data on the relationship between the intensity of pruning and the degree of damage in integrated and organic applegrowing systems." Acta Agraria Debreceniensis, no. 1 (May 27, 2001): 47–52. http://dx.doi.org/10.34101/actaagrar/1/3585.
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In Hungary, fruit growers are increasingly interested in environmentally friendly growing methods, such as organic and integrated systems. Vital is the establishment of a strengthened system of cultivar-pruning-plant protection in production technology. Consequently, our aim was to examine the susceptibility of apple cultivars to diseases and pests and the effect of pruning technique on diseases and pests in organic and integrated growing systems.Two pathogens (Venturia inaequalis, Podosphaera leucotricha) and two pests (Leucoptera malifoliella, Pannonychus ulmi) were observed in organic and integrated systems under „strong” and „weak” pruning techniques. Our results on six cultivars showed that the pathogens and pests infested the trees more in the organic system, as compared to that of integrated production. The pruning technique affected mainly the susceptiblecultivars to diseases and pests. The „weak” pruning technique caused a higher level of diseases and pests infestations than the „strong” pruning technique, especially in the organic growing system. The likely reason is that the shoots grow fast and powerfully under “strong” pruning technique. This supports better preservation of the trees supported by susceptibility of plant tissues to diseases and pests.
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Mouen Bedimo, Joseph Aubert, Bernard P. Dufour, Christian Cilas, and Jacques Avelino. "Effects of shade trees on Coffea Arabica pests and diseases." Cahiers Agricultures 21, no. 2-3 (March 2012): 89–97. http://dx.doi.org/10.1684/agr.2012.0550.
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Tubby, K. V., and J. F. Webber. "Pests and diseases threatening urban trees under a changing climate." Forestry 83, no. 4 (September 27, 2010): 451–59. http://dx.doi.org/10.1093/forestry/cpq027.
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Graziosi, Ignazio, Mathias Tembo, Jean Kuate, and Alice Muchugi. "Pests and diseases of trees in Africa: A growing continental emergency." PLANTS, PEOPLE, PLANET 2, no. 1 (June 2, 2019): 14–28. http://dx.doi.org/10.1002/ppp3.31.
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Situmorang, Lamhot, and Fristi Riandari. "Expert System Mediagnosa Hama On Phon Oil With Certainty Factor Method." Journal Of Computer Networks, Architecture and High Performance Computing 2, no. 2 (June 1, 2020): 268–74. http://dx.doi.org/10.47709/cnapc.v2i2.416.
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The process of palm oil culture is influenced by various factors, one of which is the pest and disease factors. Generally the problem of farmers differentiating pests and diseases, this is dyed most of the farmers lack information and rely on the experience of other farmers to overcome the existing pest and disease problems. In handling pests and diseases, it is necessary to have a farmer consilant who is able to diagnose pests and diseases on oil palm trees. In this study, an expert system for diagnosing pests and diseases in palm tree plants, as well as providing various solutions for pests or diseases. The method used in this expert system is the Certainty Fators method. Certainty Method The factors was chosen because this method is suitable in the process of determining the identification of pests and diseases and the result of this application is the percentage of the system. The percentage is influenced by the CF value obtained from the system, the percentage of expert system consultations is taken from the highest yield as an alternative to other pests or diseases that attack oil palm tree crops.
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Byron, Morgan, Eleanor Phillips, and Jennifer Lynn Gillett-Kaufman. "Develop Your Own Florida Olive IPM Plan." EDIS 2019, no. 4 (August 2, 2019): 10. http://dx.doi.org/10.32473/edis-in1251-2019.
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To remain in optimal health and produce optimal yield, olive trees need excellent nutrition, the right irrigation, and good care to help them stay healthy so that they can withstand injury from pests and diseases. This 10-page fact sheet written by Morgan Byron, Eleanor Phillips, and Jennifer L. Gillett-Kaufman and published by the UF/IFAS Entomology and Nematology Department touches on some aspects of olive tree health that will help improve your trees' natural resistance to pests and pathogens. At the end of the guide is a monthly care and observation schedule to help you recognize when you should begin scouting for key pests and when important grove management decisions should be made. https://edis.ifas.ufl.edu/in1251
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Magasi, Laszlo. "Insects and Diseases of the Urban Forest in the Maritimes." Arboriculture & Urban Forestry 21, no. 1 (January 1, 1995): 7–10. http://dx.doi.org/10.48044/jauf.1995.002.
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There are over 3500 insect species and over 400 diseases known to affect trees in the Maritimes. These add further stresses to trees already faced with existing environmental and urban challenges. Urban tree pests affect all parts of nearly all tree species. Insects and diseases affecting the various tree parts - foliage, shoots, twigs and branches, trunk and roots - are very briefly discussed and a few local examples are mentioned for hardwoods and conifers. Five references are cited for insect and disease identification in eastern Canada.
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Helfer, Stephan. "Plant Health and How it Affects Private Gardens: Experience from a Botanic Garden Pathologist." Sibbaldia: the International Journal of Botanic Garden Horticulture, no. 3 (October 31, 2005): 51–57. http://dx.doi.org/10.24823/sibbaldia.2005.112.
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Like many other botanic gardens the Royal Botanic Garden Edinburgh (RBGE) provides advice about plant pests and diseases to amateur gardeners. This paper summarises the main problem plant categories (such as trees and vegetables), plant problems (such as pests or fungal infection) and other observations, such as number of enquiries by month noted by pathology staff at the Garden over the last twenty years.
Dissertations / Theses on the topic "Trees Diseases and pests Victoria"
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Horner, W. Elliott. "Etiologic studies of Verticicladiella procera Kendr. in pine Christmas trees." Diss., Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/54295.
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Colonization of Pine Christmas trees by Verticicladiella procera Kendr. causes Procera root disease. Little is presently known regarding the pattern and effects of fungal development within colonized trees. The present studies were undertaken to elucidate the developmental pattern of the fungus in colonized trees, to gather information on possible mechanisms and physiological effects of disease development, and to explore the relationship between V. procera and other, well documented bluestain fungi. The presence of cellulose was demonstrated in the cell walls of X. procera, indicating the probable genetic relatedness of this fungus with Ophiostoma (Ceratocystis) bluestain fungi. Inoculation studies revealed that the fungus could penetrate wounded sapwood, and that colonized seedlings had lower water potentials than uncolonized seedlings. In addition, it was found that the fungus could persist in resinous stem lesions for 22 months without foliar symptoms, and resinous stem lesions with the fungus were significantly longer and deeper than wound lesions. An intensive isolation study revealed that the initial point of colonization in a tree is apparently at the root collar, progressing acropetally in both directions. Analysis of radial growth from increment cores showed that colonized trees had grown more slowly for the preceding three years than uncolonized trees. The sapwood moisture content of these cores was also significantly reduced in the colonized trees, indicating that the stem was drying out as symptoms developed. Histological examination of colonized sapwood showed that U fungal colonization of tissues progressed along rays and resin ducts, in a fashion similar to that of bluestain fungi. Permeability measurements demonstrated that symptomatic sapwood, either resin-soaked or black-stained, had significantly reduced water movement relative to asymptomatic sapwood.Ph. D.
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Amrhein, John Francis. "Modeling the impact of gypsy moth defoliation in individual tree mortality and basal area growth of northern hardwoods of central Pennsylvania." Thesis, Virginia Tech, 1988. http://hdl.handle.net/10919/43380.
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Data for this study were collected by the US Forest Service and the Pennsylvania Bureau of Forestry on nearly 600 plots in central Pennsylvania. Tree and stand characteristics recorded between 1978 and 1985 include estimates of percent defoliation on individual trees.
Logistic regression using maximum likelihood estimation was employed to model individual-tree mortality of 15 species in central Pennsylvania that had been defoliated by the gypsy moth. Defoliation was estimated to the nearest ten percent for individual trees. Other variables used for prediction included stand basal area and an individual-tree relative basal area index. Success ranged from no fit for three of the species to an R value (a derivation of Akaike's information criterion) of .613 for white oak. The inclusion of defoliation in the models had a varied effect. For four of the species percent defoliation was not significant. For hickory and white oak respectively, percent defoliation raised the R value by .305 and .290 percentage points. As many as five models for each species were developed: one or two models with no defoliation measure in the model and one each for one, two or three consecutive years of defoliation measures.
A beta and gamma function were used to model individual· tree basal area growth for the same 15 species. The models were fit using nonlinear least squares. Variables used include the relative basal area index, stand basal area, site index and a defoliation index that incorporated three years of individual-tree, percent defoliation. The beta and gamma functions fit equally well with values of (1 - relative mean square error) ranging from .1967 to .6290. Results for both models are presented for each species.
The defoliation index was a significant variable for five of the fifteen species: white, chestnut, red, and black oak and sassafras.Master of Science
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McConnell, Steven P. "Effects of gypsy moth defoliation on acorn production and viability, litterfall, and litter layer depth and biomass in north-central Virginia and western Maryland." Thesis, Virginia Tech, 1988. http://hdl.handle.net/10919/45883.
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The effects of gypsy moth defoliation on acorn production (the seed source for oak regeneration), and the forest floor regeneration environment were investigated. Parameters measured included: acorn quantity, weight, development, and viability; litterfall; and forest floor depth and biomass. Nineteen plots in north-central Virginia and western Maryland on which trees suffered heavy, moderate, or no defoliation were monitored over a two-year period.
Master of Science
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SWETNAM, THOMAS WILLIAM. "A DENDROCHRONOLOGICAL ASSESSMENT OF WESTERN SPRUCE BUDWORM, CHORISTONEURA OCCIDENTALIS FREEMAN, IN THE SOUTHERN ROCKY MOUNTAINS (COLORADO, NEW MEXICO)." Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/184101.
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Tree-ring chronologies from ten mixed conifer stands in the Colorado Front Ranges and New Mexico Sangre de Cristo Mountains were used to reconstruct timing, duration, and radial growth impacts of past outbreaks of western spruce budworm, Choristoneura occidentalis Freeman. Graphical and statistical comparisons of tree-ring chronologies from host and non-host tree species, in conjunction with Forest Service records of outbreaks during the twentieth century, revealed that outbreaks were identifiable only in the host chronologies as sharply reduced growth periods. These comparisons also showed that host and non-host tree-ring chronologies were generally similar between outbreaks and that both were responding in a similar manner to climatic variation. A study of defoliation and insect population data that was available for the New Mexico stands demonstrated that host radial growth from 1978 to 1983 was highly correlated with budworm activity. The non-host chronologies from each stand were used to correct the host chronologies for climatic and other non-budworm environmental variations by a differencing procedure. The corrected chronologies were then used to estimate the dates and radial growth effects of past budworm outbreaks. Tree-ring characteristics of twentieth century documented outbreaks were used as criteria for inferring the occurrence of outbreaks in previous centuries. At least nine periods of increased budworm activity were identified in the region from 1700 to 1983. The mean duration of reduced growth periods caused by known and inferred budworm outbreaks was 12.6 years, and the mean interval between initial years of successive outbreaks was 34.9 years. The mean maximum radial growth loss was 50 percent of expected growth, and the mean periodic growth loss was 21.6 percent. There was an unusually long period of reduced budworm activity in the first few decades of the twentieth century, and since that time outbreaks have been markedly more synchronous between stands. Increased synchroneity of outbreaks in the latter half of the twentieth century suggests that areal extent of outbreaks has increased. This phenomenon may be due to changes in the age structure and species composition of forests following harvesting and fire suppression in the late nineteenth and early twentieth centuries.
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Appel, Maryke. "Cloning and identification of genes involved in the interaction between the bacterial stone fruit pathogen Pseudomonas syringae pv. syringae strain NV and plum trees." Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52165.
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Thesis (PhD)--Stellenbosch University, 2001.ENGLISH ABSTRACT: Bacterial canker of stone fruit, caused by Pseudomonas syringae pv. syringae, is one of the most destructive crop diseases in South Africa. Chemical control has failed completely and effective long-term management strategies will have to rely on the breeding of resistant host trees. To assist in such breeding programmes, investigations into the molecular basis of the interaction between P. s. pv. syringae and stone fruit trees have been undertaken in collaboration with the ARC-Fruit, Wine and Vine Research Institute in Stellenbosch. The aim of this dissertation was to clone and identify genes that are involved in interaction between the bacterial canker pathogen and stone fruit trees. In the first part of the study, the harpin encoding gene of a local strain of the pathogen, P. s. pv. syringae NV, was amplified in a polymerase chain reaction (PCR) strategy with primers based on the hrpAZB sequences of the bean pathogen, P. s. pv. syringae 61. Sequencing of this hrpZpssNvgene revealed a high degree of homology (96%) between the harpin encoding genes and harpin proteins of the two strains. The hrpZpssNvgene was subsequently cloned into the pMAL-c2 expression vector and expressed in Escherichia co/i. This system was used for the production of purified, biologically active, recombinant HrpZpSSNV protein. In the second part of the study, differential display (DD) technology was used to identify genes that are induced in stone fruit trees in response to P. s. pv. syringae and/or its harpin elicitor. For this purpose, actively growing shoots of two Prunus sa/icina cultivars, the moderately resistant cv. 'Laetitia' and the highly susceptible cv. 'Songold' were treated with recombinant harpinpssNvprotein or live P. s. pv. syringae NV bacteria. An untreated control and wounding control was included in the experiment. Total RNA was isolated for comparative mRNA analysis 24 hours after treatment. DD profiles were generated with fifteen primer combinations. Eight candidate bands were re-amplified, cloned and sequenced. Reverse transcription PCR was employed to verify the expression patterns of the cloned bands in the original RNA sample set. Two bands, DDc and DD4 were shown to be differentially expressed between treatments and/or cultivars, while no differences in the expression levels of the remaining six bands (DDa, DDe, DD3, DD5, DD6 and DD7) were observed. BLAST similarity searches yielded significant matches for DDe, DD4 and DD7 with plant defense-related genes.
AFRIKAANSE OPSOMMING: Bakteriese kanker van steenvrugte, wat deur Pseudomonas syringae pv. syringae veroorsaak word, is een van die mees verwoestende siektes van landbougewasse in Suid-Afrika. Chemiese beheermaatreëls het geheel en al misluk en effektiewe langtermyn beheerstrategieë sal op die teling van weerstandbiedende gasheerbome moet staatmaak. Ondersoeke na die molekulêre basis van die interaksie tussen P. s. pv. syringae en steenvrugbome is in samewerking met die LNR-Vrugte-, Wyn- en Wingerdnavorsingsinstituut in Stellenbosch van stapel gestuur om tot sulke telingsprogramme by te dra. Die doelwit van hierdie proefskrif was om gene wat betrokke is in die interaksie tussen die bakteriese kanker patogeen en steenvrugbome te kloneer en te identifiseer. In die eerste gedeelte van die studie is die harpien-koderende geen van 'n plaaslike ras van die patogeen, P. s. pv. syringae NV, geamplifiseer in 'n polimerase kettingreaksie (PKR)-strategie met peilers wat op die hrpAZB-geenopeenvolgings van die boontjiepatogeen, P. s. pv. syringae 61, gebaseer is. Volgordebepaling van hierdie hrpZpssNv-geen het 'n hoë vlak van homologie (96%) tussen die harpien-koderende gene en harpien proteïene van die twee rasse getoon. Die hrpZpssNv-geen is vervolgens in die uitdrukkingsvektor pMAL-c2 gekloneer en uitgedruk in Escherichia coli. Hierdie sisteem is vir die produksie van suiwer, biologies-aktiewe, rekombinante HrpZpssNv-proteingebruik. In die tweede gedeelte van die studie is die differensiaalvertoon (DD) tegniek gebruik om gene te identifiseer wat deur P. s. pv. syringae en/of sy harpien elisitar in steenvrugbome geïnduseer word. Vir hierdie doel is aktief-groeiende lote van twee Prunus sa/icina kultivars, die matig weerstandbiedende kv. 'Laetitia' en die hoogs vatbare kv. 'Songold', met rekombinante harpienpssNvproteïen of lewende P. s. pv. syringae NV bakterieë behandel. 'n Onbehandelde- en verwondingskontrole is in die eksperiment ingesluit. Totale RNA is 24 uur na behandeling vir vergelykende mRNA-analise geïsoleer. DD-profiele is met vyftien peilerkombinasies gegenereer. Agt kandidaatbande is geheramplifiseer en gekloneer, waarna hul DNA-opeenvolgings bepaal is. Trutranskriptase-PKR is gebruik om die ekspressiepatrone van die gekloneerde bande in die oorspronklike RNA monsters na te gaan. Daar is vasgestel dat twee van die bande, DDc en DD4, differensieel tussen kultivars en/of behandelings uitgedruk is, terwyl geen verskille in die ekspressievlakke van die oorblywende ses bande (DDa, DOe, 003, DOS, 006 en DO7) waargeneem is nie. BLAST-soektogte het betekenisvolle ooreenkomste vir DDe, DD4 en DD7 met plant weerstandsgeassosieerde gene opgelewer.
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Granger, Gregory. "Relationships between Potential Rooting Depth, Tree Growth, and White Pine (Pinus Strobus L.) Decline in Southern Maine." Fogler Library, University of Maine, 2004. http://www.library.umaine.edu/theses/pdf/GrangerG2004.pdf.
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McNamee, Peter James. "The equilibrium structure and behavior of defoliating insect systems." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/27439.
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Defoliating insect systems, defined for the purposes of this thesis as being composed of insects which defoliate forest trees and the species with which they interact, such as their host trees and their natural enemy complexes, exhibit
a wide variety of population behaviors. Similarly, a number of theories and models have been proposed to explain these behaviors. These theories emphasize the importance of different ecological processes, often concentrate on the defoliator and overlook the importance of other components. Also, much of the current understanding of the dynamics of these systems has come from forest pest research and management
programs, tailored towards specific pest problems and often very short term in nature.
This thesis develops and begins to test a general approach for the local dynamics of defoliating insect systems.
This framework outlines the system components that are necessary to predict the behavior of defoliating insect systems. It includes ways in which the equilibrium structure
of defoliating insect systems, defined as the number of equilibria for each system component, the population levels at which the equilibria occur, and the processes creating the equilibria, might be found. The framework also includes methods of inducing the qualitative behavior of these sys- terns, defined as the periodicity of defoliator outbreaks, the length of outbreaks, and the dynamics of other important system components between, during, and in the decline of defoliator outbreaks.
The study begins with a detailed literature review of historical theories of defoliating insect system behavior and of the documented behavior patterns of these systems. Major classes of behavior are identified, as well as the various ecological processes which have been invoked to explain these behaviors. An analysis and documentation of the equilibrium structure and behavior of three defoliating defoliating insect systems, the eastern blackheaded budworm, the eastern spruce budworm, and the jack pine sawfly, are then used to develop general rules about how equilibrium structure and behavior can be explained. This analysis, coupled with the literature review, is used to develop the framework. The framework is then tested against historical defoliator population data and general syntheses of defoliating
insect system research to assess its utility and predictability.
The major results of the thesis are as follows. First, it appears that the structure and behavior of a defoliating insect system can be explained with five dynamic variables: the abundances of the defoliator; the foliage; the forest; the parasitoid; and the disease; and the effects of weather acting on the defoliator. Second, there appear to be 4 classes of defoliating insect system behavior. Third, the behavior that a defoliating insect system will exhibit seems to be determined by the magnitude of weather effects on defoliator survival and recruitment, the parasitoid numerical
response to changing defoliator densities, the disease numerical response to changing defoliator densities, and the vulnerability of the forest to defoliation. Fourth, there seem to be four equilibrium structures the defoliator can exhibit, and one each for the parasitoid, the foliage, the forest, and the disease. Finally, the framework suggests that defoliating insect system structure and behavior can be induced with a particular, well-defined set of information.
The framework is successful when applied to particular defoliating insect systems for explaining their behavior, but less successful in explaining defoliator equilibrium structure for other systems. Opportunities for more thorough testing of the framework exist if the particular types of data outlined above are gathered for defoliating insect systems. This lack of data for testing the framework make it currently difficult to clearly define those systems in which the framework is useful and those systems in which it is not. Experiments to test the framework are described and suggestions for future types of applied research on defoliating insect systems are presented.Science, Faculty of
Zoology, Department of
Graduate
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Daniel, Colin John. "Climate and outbreaks of the forest tent caterpillar in Ontario." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/28957.
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A review of the current understanding of forest tent caterpillar (Malacosoma disstria Hbn.) population dynamics in Ontario suggests that two climatic factors, the temperature at the time of larval feeding and the minimum temperature through the winter, play important roles in determining outbreaks. Comparing the pattern of defoliation to similarly scaled temperature records over 41 years in Ontario shows no relationship between the year to year dynamics of outbreaks and either the temperature through the larval feeding period or the minimum overwintering temperature. A long-term analysis suggests that outbreaks are less severe in those regions with low overwintering temperatures and a patchy distribution of host. This latter finding, combined with an analysis of the synchrony and spread of defoliation, suggests that adult dispersal may play an important role in shaping the dynamics of outbreaks.Science, Faculty of
Zoology, Department of
Graduate
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Machingambi, Netsai. "An investigation into the death of native Virgilia trees in the Cape Floristic Region of South Africa." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/79902.
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Thesis (MSc)--Stellenbosch University, 2013.ENGLISH ABSTRACT: The Cape Floristic Region (CFR) of South Africa is well-recognised for exceptionally high plant species diversity and endemism. However, little attention has been bestowed on the pests and pathogens in this region, even though these may greatly influence plant distribution and evolution. In this study we identify various arthropods and fungi as pests and diseasecausing organisms of the ecologically and economically important CFR-endemic tree taxa of Virgilia. We isolated, identified and determined the pathogenicity of key fungal taxa from diseased Virgilia trees throughout the CFR. In addition we evaluated the role of possible pest arthropod taxa, including bark beetles, phoretic mites, larvae of a cerambycid beetle and larvae of the endemic Leto venus (ghost moth), in the death of Virgilia trees. Key fungal taxa were identified by comparisons of the internal transcribed spacer rDNA regions of the isolated taxa with those available on GenBank. Pathogenicity of the most commonly encountered fungal taxa was determined both in the field and under greenhouse conditions. Five different disease symptoms were observed on Virgilia trees throughout the CFR. At Table Mountain, Virgilia oroboides subsp. oroboides showed symptoms of: (1) several small cankers on stems, seemingly caused by a Fusarium acuminatum-like fungus, (2) a root rot disease caused by Armillaria mellea and (3) small bracket fungi on stems associated with Schizophyllum commune. Virgilia oroboides from the Harold Porter National Botanical Garden was diagnosed with a root disease consistently associated with an un-described Phomopsis species. Virgilia oroboides subsp. ferruginea and V. divaricata from Knysna and the Tsitsikamma area often showed symptoms of rapid wilting and death. The Virgilia stems were damaged by the tunnelling larvae of the ghost moth and those of an unidentified cerambycid beetle. Galleries and the surrounding wood tissues often housed the ophiostomatoid fungi Ceratocystis tsitsikammensis and Ophiostoma plurianulatum. These seem to originate from nitidulid beetles found feeding on gum exudate. Pathogenicity trials confirmed the virulence of the undescribed Phomopsis species, the F. acuminatum-like fungus, S. commune and C. tsitsikammensis to Virgilia. All four morpho-species of bark beetles found in this study, together with phoretic mites on two of the beetle morphospecies, were only collected from dead and dying Virgilia hosts and were classified as secondary pests. Both beetle taxa and mites commonly carried spores of various Geosmithia spp. These are not pathogenic to Virgilia trees, but may be an important food source for the bark beetles, as it dominated the fungal community in galleries. The phoretic mites were unable to feed on their Geosmithia associates, but have been observed to feed on dead bark beetle larvae within galleries. This suggests that the relationship of bark beetles, mites and their associated Geosmithia species in this system is complex and in need of further study. Our results show that natural populations of Virgilia play host to numerous destructive pathogens, some of which are non-native (e.g. A. mellea) and a cause for special concern. Additionally, the isolation of the undescribed Phomopsis species and A. mellea from botanical gardens, with A. mellea now spreading to natural areas, calls for stricter control over the movement of organic material from these areas.
AFRIKAANSE OPSOMMING: Die Kaapse Floristiese Streek (KFS) van Suid-Afrika is bekend vir buitengewoon hoë plantspesie-diversiteit en endemisme. Min aandag is egter tot dusver geskenk aan die peste en patogene in hierdie streek, al mag hulle plantverspreiding en evolusie dramaties beinvloed. In hierdie studie identifiseer ons verskeie geleedpotige diere en fungi as peste en organismes wat siektes veroorsaak in die ekologies en ekonomies belangrike, KFS-endemiese boom genus Virgilia. Ons het die sleutel fungi vanaf Virgilia oor die hele KFS geisoleer, geidentifiseer en hulle patogeniteit bepaal. Addisioneel het ons ook die rol van moontlike pes geleedpotiges, insluitende baskewers, cerambycid kewerlarwes en die endemiese Leto venus (spookmot) in die dood van Virgilia bome geevalueer. Sleutel fungi taksa is geidentifiseer deur die interne getranskribeerde spasieerder rDNS streke van die geisoleerde taksa met die wat op GenBank beskikbaar was te vergelyk. Patogenisiteit van die mees algemeen geisoleerde fungi taxa is beide in die veld en onder glashuis-toestande bepaal. Vyf verskillende siekte simptome is by Virgilia bome regdeur die KFS waargeneem. By Tafelberg het Virgilia oroboides subsp. oroboides simptome getoon van: (1) verskeie klein kankers op stamme, blykbaar veroorsaak deur ‘n Fusarium acuminatum-agtige fungus, (2) ‘n wortelvrot siekte veroorsaak deur Armillaria mellea en (3) klein rakswamme op stamme geassosieer met Schizophyllum commune. Virgilia oroboides in die Harold Porter Nationale Botaniese Tuin is gediagnoseer met ‘n wortelvrot siekte wat altyd met ‘n onbeskryfde Phomopsis spesie geassosieer is. Virgilia oroboides subsp. ferruginea and V. divaricata van Knysna en die Tsitsikamma area het dikwels simptome getoon van vinnige verwelking en dood. Die Virgilia stamme is deur die tonnelende larwes van die spookmot en dié van ‘n ongeidentifiseerde cerambycid kewer beskadig. Galerye en die omringende houtweefsel het dikwels die ophiostomatoid fungi Ceratocystis tsitsikammensis en Ophiostoma plurianulatum gehuisves. Dit lyk asof hierdie fungi van nitidulid kewers afkomstig is wat op die gomuitskeidings gevoed het. Patogeniteitsproewe het die kwaadaardigheid van die onbeskryfde Phomopsis spesie, die F. acuminatum-agtige fungus, S. commune en C. tsitsikammensis teenoor Virgilia bevestig. Al vier morfo-spesies baskewer wat in hierdie studie gevind is, sowel as die foretiese myte op twee van die kewer morfo-spesies, is slegs van dooie of sterwende Virgilia gashere versamel, en is as sekondêre peste geklassifiseer. Beide kewerspesies en myt taksa het algemeen spore van verskeie Geosmithia spesies (Geosmithia pallida, G. flava, G. microcorthyli, G. sp. 1 en G. sp. 2) gedra. Die Geosmithia spesies is nie patogenies teenoor Virgilia bome nie, maar mag ‘n belangrike voedselbron vir die baskewers wees, aangesien dit die fungus-gemeenskap in die galarye gedomineer het. Die foretiese myte was nie instaat om op Geosmithia-assosiate te voed nie, maar is waargeneem om op dooie baskewer larwes te voed binne die galerye. Dit stel voor dat die verhouding van die baskewers, myte en hulle geassosieerde Geosmithia spesies in die sisteem kompleks is, en verdere studie benodig. Ons resultate dui aan dat natuurlike populasies van Virgilia gashere is vir verskeie destruktiewe patogene, sommige waarvan nieinheems (bv. A. mellea) wat ‘n bron van groot kommer is. Verder noodsaak die isolasie van die Phomopsis spesie en A. mellea, wat beide wortelvrot siektes in botaniese tuine veroorsaak, strenger kontrole oor die verskuiwing van organiese materiaal uit hierdie areas, veral gegewe dat A. mellea reeds na natuurlike areas versprei het.
The Centre of Excellence In Tree Health Biotechnology for a bursary and funding the research conducted in this study
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Van, Jaarsveld Alwyn Jacobus. "Plant parasitic organisms in the rizosphere of apple trees in the Western Cape, with special reference to woolly apple aphid." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53551.
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Thesis (MScAgric)--University of Stellenbosch, 2003.ENGLISH ABSTRACT: Various aspects of the biology and ecology of woolly apple aphid, Eriosoma lanigerum, were investigated, including initial galling damage caused by E. lanigerum to the roots of apple trees, the possible relationship between E. lanigerum and Xiphinema and Pratylenchus nematodes and the effectiveness of Biostart 2000® and Furfural® as possible control agents of E. lanigerum in the orchard. Preliminary root damage by first instar E. lanigerum feeding was characterized by the mechanical injury of endodermis and parenchyma tissues. Damage by second, third and fourth instar E. lanigerum was similar, but the symptoms were more pronounced. Damage caused by adults included a pronounced swelling at infected areas of the root. Cell walls hardened until the root was radially strengthened with sclerenchyma tissue and nonconducting xylem vessels while the cuticle expanded greatly through the growth of corklike cambium tissue. There was no direct relationship between the population dynamics of E. lanigerum and those of Xiphinema and Pratylenchus nematodes. The occurrence of E. lanigerum appeared to be seasonal while P. penetrans and Xiphinema numbers fluctuated erratically. Undamaged root nitrogen levels seemed to correspond with the normal root growth cycle. Nitrogen levels from galled roots were significantly lower than those of undamaged roots, probably due to E. lanigerum feeding. Soils rich in fine sand and clay sustained higher populations of E. lanigerum and Xiphinema than sandy soils. The number of E. lanigerum found in soil samples correlated well with the damage index allocated to the samples. The numbers of Xiphinema found in soil samples also correlated well with the damage index allocated to the samples according to suspected Xiphinema damage symptoms. Both Biostart 2000® and Furfural® were effective as control agents of woolly apple aphid. Furfural'Ï, a chemical waste product of the sugarcane industry, was however not as effective as Biostart 2000®, a product that includes an activator and three bacterial species, Bacillus laterosporus, B. chitinosporus and B. licheniformis. The bacteria in the Biostart 2000® treated pots could replicate themselves under suitable conditions while Furfural® dilutes with each watering. Biostart 2000® is also easier to prepare than Furfural® since the components of Biostart 2000® readily mix to form a paste easily thinned by water, whereas Furfural® is an oily substance that does not easily disperse in water. Root damage was initiated soon after E. lanigerum started feeding, however there was no apparent relationship between E. lanigerum and the nematode species. The most promising, environmentally friendly control measure was Biostart 2000®.
AFRIKAANSE OPSOMMING: Verskeie aspekte van biologie en die ekologie van die appel bloedluis, Eriosoma lanigerum, was ondersoek insluitende aanvanklike galvorming veroorsaak deur E. lanigerum op wortels van appelbome, die moontlike verwantskap tussen E. lanigerum en Xiphinema en Pratylenchus nematodes en die effektiwiteit van Biostart 2000® en Furfural® as moontlike beheeragente van E. lanigerum in die boord. Aanvanklike wortelskade deur eerste ins tar E. lanigerum voeding was gekenmerk deur die meganiese beskadiging van endodermale en parenchiem weefsel. Skade veroorsaak deur tweede, derde en vierde instar E. lanigerum was soortgelyk alhoewel die simptome meer beklemtoond was. Skade deur volwassenes het 'n meer duidelike swelsel by geïnfekteerde wortelareas ingesluit. Selwande het verhard totdat die wortel radiaalsgewys versterk was met skierenchiem weefsel en nie-geleidende xileemvate terwyl die kutikula grootliks toegeneem het deur die groei van kurkagtige kambiumweefsel. Daar was geen direkte verwantskap tussen die bevolkingsdinamika van E. lanigerum en dié van Xiphinema en Pratylenchus nematodes nie. Die voorkoms van E. lanigerum was seisoenaal terwyl P. penetrans en Xiphinema se getalle onvoorspelbaar gefluktueer het. Onbeskadigde wortel stikstofvlakke het ooreengestem met die normale wortel groeisiklus. Stikstof vlakke van galwortels was noemenswaardig laer as dié van onbeskadigde wortels, heel waarskynlik as gevolg van voeding deur E. lanigerum. Grond ryk aan fyn sand en klei het groter bevolkings van E. lanigerum en Xiphinema onderhou as sanderige gronde. Die aantal E. lanigerum in grondmonsters het goed ooreengestem met die skade indeks wat aan die monsters toegeken was. Die aantal Xiphinema in grondmonsters het ook goed ooreengestem met die beskadigingsindeks wat aan die monsters toegeken is weens vermoedelike Xiphinema skade simptome. Beide Biostart 2000® en Furfural® was effektief as beheeragente van die appelbloedluis. Furfural'", 'n afvalproduk van die suikerriet industrie, was egter minder effektief as Biostart 2000®, 'n produk bestaande uit 'n aktiveerder en drie bakterie spesies, Bacillus laterosporus, B. chitinosporus en B. licheniformis. Die bakterië in die Biostart 2000® behandelde potte kon vermeerder onder gunstige toestande terwyl Furfural® na elke besproeiing verdun het. Biostart 2000® is ook makliker om aan te maak as Furfural® aangesien die bestanddele van Biostart 2000® geredelik meng tot 'n wateroplosbare pasta, terwyl Furfural® 'n olierige vloeistofis wat moeilik 'n waterige suspensie vorm. Wortelskade het plaasgevind kort nadat E. lanigerum begin voed het, alhoewel daar geen duidelike verwantskap tussen E. lanigerum en nematode spesies voorgekom het nie. Die mees belowende omgewingsvriendelike beheermaatreël was Biostart 2000®.
Books on the topic "Trees Diseases and pests Victoria"
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R, Sutherland Jack, Glover S. G, and Pacific Forestry Centre, eds. Proceedings of the first meeting of IUFRO Working Party S2.07-09 (Diseases and Insects in Forest Nurseries): Victoria, British Columbia, Canada, August 23-30, 1990. Victoria: Pacific Forestry Centre, 1991.
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H, Lyon Howard, and Johnson Warren T, eds. Diseases of trees and shrubs. Ithaca: Comstock, 1989.
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Sinclair, Wayne A. Diseases of trees and shrubs. Ithaca, N.Y: Comstock Pub. Associates, 1987.
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Sinclair, Wayne A. Diseases of trees and shrubs. 2nd ed. Ithaca, N.Y: Cornell University Press, 2005.
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Virus diseases of trees and shrubs. 2nd ed. London: Chapman & Hall, 1993.
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(Canada), Northern Forestry Centre, ed. Forest tree diseases of the prairie provinces. Edmonton: Northern Forestry Centre, Canadian Forestry Service, 1987.
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Riffle, Jerry W. Diseases of trees in the Great Plains. Fort Collins, Colo: U.S. Dept. of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station, 1986.
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Riffle, Jerry W. Diseases of trees in the Great Plains. Fort Collins, Colo: U.S. Dept. of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station, 1986.
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Johnson, Dennis A. Leaf scorch of shade trees. Pullman, [Wash.]: Cooperative Extension, College of Agriculture and Home Economics, Washington State University, 1986.
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Blodgett, Earle Comstock. Why cherry trees die. [Pullman, Wash.]: Cooperative Extension, Washington State University, 1990.
Find full textBook chapters on the topic "Trees Diseases and pests Victoria"
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Zhi-jun, Wang, Liu Xin, Jiang Meng, and Cheng Shu-han. "The Application of Image Retrieval Technology in the Prevention of Diseases and Pests in Fruit Trees." In Computer and Computing Technologies in Agriculture VII, 160–67. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-54344-9_20.
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Rizzo, Maria, and Patrizia Gasparini. "Forest Health." In Springer Tracts in Civil Engineering, 447–68. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-98678-0_10.
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AbstractForests mainly consist of long-lived trees or shrub species and are exposed to natural or human disturbances of different severities. They are essential components of the natural development of forest ecosystems, since by triggering natural selection and ecological succession processes, they can achieve the best status in terms of species composition and structure. Nevertheless, extreme events can cause serious economic or naturalistic losses and, in some cases, endanger specific forest ecosystems. Disturbance events that damage forests vary and include pests and diseases, fires, pollution, climate changes, overexploitation or inadequate silvicultural practices, excessive grazing and browsing, to name just a few. Health monitoring of forests is a necessary condition to provide useful information for the conservation of forest resources, as well as to support forest management practices aimed at increasing the resilience of forests and their adaptation capacity. Through ground surveys, the Italian national forest inventory INFC has classified the health condition of Italian forests and produced the estimates presented in the chapter. These concern the distribution of the Forest area by pathologies and damage presence, severity and cause. Estimates of the Forest area affected by defoliation, divided by defoliation class and localization of defoliation, are also presented.
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Sol Sánchez, Ángel, Gloria Isela Hernández Melchor, and Facundo Sánchez Gutiérrez. "Main Pests and Diseases in Tropical Forest Species in Nursery." In Current and Emerging Challenges in the Diseases of Trees [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.107028.
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This paper presents the monitoring of pests and diseases in nurseries of 10 tropical forest species used in the reforestation of disturbed areas. The work was carried out in a rustic nursery established in Cardenas, Tabasco, under cocoa shade. The objective was to evaluate the presence of pests or diseases in the nursery under natural conditions. Pests and diseases appeared from the seedling stage in germination beds to the adult stage. The fungus Fusarium was the most aggressive causal agent that caused the death of seedling in the germination beds, as well as Curvularia lanata that massively affected Tabebuia rosea plants. Likewise, T. rosea is one of the species with the most reported pests, as well as Lantana camara. On the contrary, Hamelia patens Jacq (Coralillo) did not registered important pests during the monitoring in the nursery.
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Kankam, Frederick, Stephen Larbi-Koranteng, Joseph Adomako, Joseph Kwowura Kwodaga, Isaac Boatey Akpatsu, Yaw Danso, and Elias Nortaa Kunedeb Sowley. "Anthracnose Disease of Mango: Epidemiology, Impact and Management Options." In Current and Emerging Challenges in the Diseases of Trees [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.105934.
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Mango is one of the frequently cultivated seasonal fruit crops in several tropical and subtropical regions. It is consumed as whole fruits apart from serving as raw materials for most industries that are into mineral production. Mango production is, however, constrained by diseases, pests, and poor post-harvest handling of fruits. Anthracnose disease, caused by Colletotrichum gloeosporioides Penz and Sacc, is one of the most important yields limiting constraint in mango production across the globe. The disease occurs in both the field and post-harvesting. In the field, it affects aboveground parts, such as the stem, branches, leaves, flowers, and fruits. Anthracnose disease reduces the shelve life and marketability of mango fruit. In Ghana, anthracnose disease is responsible for about 30% yield/fruit loss. Most farmers do not control it, although some have resorted to the application of various fungicides not registered for mango anthracnose disease management in Ghana. This chapter will highlight on the importance of the disease on the mango industry in Ghana, control strategies currently employed thereby reducing the over-reliance on chemical control option and propose ways to minimize the effect of the disease in the country.
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Matsushita, Koji. "Legal and Administrative Aspects of Forest Pest and Disease Control in Japan." In Silviculture [Working Title]. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.95005.
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Approximately 40% of Japanese forests are softwood plantations consisting of trees such as Japanese cedar (Cryptomeria japonica), Japanese cypress (Chamaecyparis obtusa), and several varieties of pine (Pinus spp.). Policies and programs related to forest pests and diseases are important for growing forest plantations. Damage caused by the pine bark beetle (Monochamus alternatus) has been a long-standing problem in Japan. Forest damage caused by the pine bark beetle was first found in Nagasaki Prefecture in 1905. Since then, the area of damage has expanded gradually to all prefectures. Damage caused by pine bark beetles became serious during and just after the end of the Second World War. In 1950, the Natural Resource Section of the General Headquarters of the Allied Forces, Supreme Commander for the Allied Powers (GHQ/SCAP) made recommendations for how to control forest pests and diseases. The first act was enacted in 1950, although the control of forest pests was initially addressed as part of the first Forest Act of 1897. Several important reasons for why the Japanese government has failed to stop the expansion of the damaged area can be found in GHQ recommendations: the lack of coordinated programs, underutilization of damaged trees, and shortcomings of forest-management plans.
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Chen, Wei. "Modeling Design and Aesthetic Analysis of Trunk Liquid Medicine Injection Machine." In Advances in Transdisciplinary Engineering. IOS Press, 2022. http://dx.doi.org/10.3233/atde220532.
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Trunk medicine liquid injection machine is a relatively advanced spraying tool, which is mainly used to control plant diseases and insect pests in forests, urban gardens, trees on both sides of roads and streets, windbreak forest belts in rural areas and orchards. In the design of trunk medicine liquid injection machine, we should pay attention to not only the structure design, but also the modeling design. Starting from the function of trunk injection liquid machine, the design requirements are put forward. According to its structure, working principle and performance characteristics, the product modeling is planned, designed and aesthetically analyzed. The application shows that the machine can meet the requirements of pest control and disease control, and also meet the design requirements. It has beautiful and novel shape, convenient use and modern feeling.
Conference papers on the topic "Trees Diseases and pests Victoria"
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Huang, Jiayi /., Mengxi /. Zeng, Weixia /. Li, and Xiangbao /. Meng. "Application of Data Augmentation and Migration Learning in Identification of Diseases and Pests in Tea Trees." In 2019 Boston, Massachusetts July 7- July 10, 2019. St. Joseph, MI: American Society of Agricultural and Biological Engineers, 2019. http://dx.doi.org/10.13031/aim.201900919.
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Kuklina, T. E., and O. L. Konusova. "ON THE STATE OF ULMUS LAEVIS PALL. IN THE URBAN ENVIRONMENT." In Prirodopol'zovanie i ohrana prirody: Ohrana pamjatnikov prirody, biologicheskogo i landshaftnogo raznoobrazija Tomskogo Priob'ja i drugih regionov Rossii. Izdatel'stvo Tomskogo gosudarstvennogo universiteta, 2020. http://dx.doi.org/10.17223/978-5-94621-954-9-2020-46.
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An assessment of the state of Ulmus laevis plantings in the urban environment was carried out on the example of Tomsk. Biometric characteristics and indicators of the viability of trees in street and boulevard plantings have been established. Information about pests and diseases of elm affecting its vital condition and decorative qualities has been obtained.
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Chen, Gang, Richard K. Chang, Paul Nachman, Ronald G. Pinnick, Steven C. Hill, Gilbert L. Fernandez, and Michael W. Mayo. "Measurement of laser-excited fluorescence spectra of individual airborne biological particles." In Biomedical Optical Spectroscopy and Diagnostics. Washington, D.C.: Optica Publishing Group, 2006. http://dx.doi.org/10.1364/bosd.1996.ca4.
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We are developing laser based fluorescence particle counters and spectrum analyzers which should be useful for real-time monitoring of airborne bacteria, proteins or other particles. Improved methods for detecting and characterizing airborne particles could be useful in applications such as studying the spread of diseases of plants, animals, and humans, or determining the sources of particles in clean rooms. Many airborne bacteria, pollens and viruses are of medical, agricultural, or ecological interest. Some diseases of humans (e.g., tuberculosis), of farm animals, of agricultural crops, and of forest trees are commonly transmitted through the air. Some airborne pollens cause allergies in humans. Bacteria (e.g., Bacillus thuringensis) used to control certain pests are commonly disseminated through the air.
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Yakimov, N. I., V. V. Nosnikov, and A. V. Yurenya. "RATIONAL USE OF LAND DERIVED FROM AGRICULTURAL USE." In STATE AND DEVELOPMENT PROSPECTS OF AGRIBUSINESS Volume 2. DSTU-Print, 2020. http://dx.doi.org/10.23947/interagro.2020.2.310-313.
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The article discusses the use of former agricultural lands for afforestation. The fertility of these lands is reduced, low biological activity of soils is noted, the content of substances inhibiting the growth of woody plants is observed. The presence of a compacted subsurface layer contributes to the fact that the root systems of trees are formed by surface and do not reach groundwater. Created forest plantations usually experience a water supply crisis, they die off in dry years, they are easily exposed to diseases and pests. Possible ways of solving problems associated with afforestation in this category of land are suggested.
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Zamiusskaya, E., V. Koza, and Tat'yana Kramareva. "CONDITION OF FIELD PROTECTIVE STRIPS IN CONDITIONS OF STEPPE ZONE OF VORONEZH REGION." In Modern problems of animal and plant ecology. FSBE Institution of Higher Education Voronezh State University of Forestry and Technologies named after G.F. Morozov, 2021. http://dx.doi.org/10.34220/mpeapw2021_15-19.
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The paper presents the results of studies of protective strips located in the Voronezh region in the Rossoshansky district. The characteristic of biometric data of forest belts of the same age and their dependence on the density of planting, width of strips and row spacing is given. The comparison of the soil, its impact on the growth and development of trees is displayed. The influence of the design of protective forest stands on the temperature of the surface air layer is also shown. The state of the plantings and the factors that adversely affect it are determined: the lack of care measures, deforestation, clutter and the presence of a large number of diseases and pests.
Reports on the topic "Trees Diseases and pests Victoria"
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Davis, Cristina, Amots Hetzroni, Alexander Aksenov, Michael J. Delwiche, Victoria Soroker, and Victor Alchanatis. Development of a universal volatile compound detection technology for early recognition of pests and diseases in fruit trees. United States Department of Agriculture, January 2015. http://dx.doi.org/10.32747/2015.7600016.bard.
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Amanor, Kojo, Joseph Yaro, Joseph Teye, and Steve Wiggin. Ghana’s Cocoa Farmers Need to Change Gear: What Policymakers Need to Know, and What They Might Do. Institute of Development Studies (IDS), March 2022. http://dx.doi.org/10.19088/apra.2022.008.
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Cocoa farmers in Ghana face increasing challenges. In the past, many of them could make a living from cocoa thanks to the advantages – ‘forest rents’ – that initially apply when forest is cleared to create cocoa farms: fertile soils, few pests and diseases. With time, however, weeds invade, pests and diseases build up, and trees age. To maintain production requires more labour, more inputs and more skill. In the past, farmers would often abandon older groves and seek new forest to clear. As they did so, the frontier for cocoa farming moved westwards across Ghana to the remaining high forest. But by 2000 or so, no new forest was available. Farmers now have to manage aging stands of trees, clear weeds and parasites, and combat pests, fungi and diseases. In Suhum District in the east and in Juaboso District in the far west of Ghana, we talked to farmers. They understood the challenges they faced, and knew how to deal with some of them. But many were not farming their cocoa as well as they could, losing yields and income as a result. This brief provides a basis for policymakers to move forward in responding to the current challenges facing cocoa farmers.
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Cohen, Yuval, Christopher A. Cullis, and Uri Lavi. Molecular Analyses of Soma-clonal Variation in Date Palm and Banana for Early Identification and Control of Off-types Generation. United States Department of Agriculture, October 2010. http://dx.doi.org/10.32747/2010.7592124.bard.
Full textAbstract:
Date palm (Phoenix dactylifera L.) is the major fruit tree grown in arid areas in the Middle East and North Africa. In the last century, dates were introduced to new regions including the USA. Date palms are traditionally propagated through offshoots. Expansion of modern date palm groves led to the development of Tissue Culture propagation methods that generate a large number of homogenous plants, have no seasonal effect on plant source and provide tools to fight the expansion of date pests and diseases. The disadvantage of this procedure is the occurrence of off-type trees which differ from the original cultivar. In the present project we focused on two of the most common date palm off-types: (1) trees with reduced fruit setting, in which most of the flowers turn into three-carpel parthenocarpic fruits. In a severe form, multi-carpel flowers and fruitlets (with up to six or eight carpels instead of the normal three-carpel flowers) are also formed. (2) dwarf trees, having fewer and shorter leaves, very short trunk and are not bearing fruits at their expected age, compared to the normal trees. Similar off-types occur in other crop species propagated by tissue culture, like banana (mainly dwarf plants) or oil palm (with a common 'Mantled' phenotype with reduced fruit setting and occurrence of supernumerary carpels). Some off-types can only be detected several years after planting in the fields. Therefore, efficient methods for prevention of the generation of off-types, as well as methods for their detection and early removal, are required for date palms, as well as for other tissue culture propagated crops. This research is aimed at the understanding of the mechanisms by which off-types are generated, and developing markers for their early identification. Several molecular and genomic approaches were applied. Using Methylation Sensitive AFLP and bisulfite sequencing, we detected changes in DNA methylation patterns occurring in off-types. We isolated and compared the sequence and expression of candidate genes, genes related to vegetative growth and dwarfism and genes related to flower development. While no sequence variation were detected, changes in gene expression, associated with the severity of the "fruit set" phenotype were detected in two genes - PdDEF (Ortholog of rice SPW1, and AP3 B type MADS box gene), and PdDIF (a defensin gene, highly homologous to the oil palm gene EGAD). We applied transcriptomic analyses, using high throughput sequencing, to identify genes differentially expressed in the "palm heart" (the apical meristem and the region of embryonic leaves) of dwarf vs. normal trees. Among the differentially expressed genes we identified genes related to hormonal biosynthesis, perception and regulation, genes related to cell expansion, and genes related to DNA methylation. Using Representation Difference Analyses, we detected changes in the genomes of off-type trees, mainly chloroplast-derived sequences that were incorporated in the nuclear genome and sequences of transposable elements. Sequences previously identified as differing between normal and off-type trees of oil palms or banana, successfully identified variation among date palm off-types, suggesting that these represent highly labile regions of monocot genomes. The data indicate that the date palm genome, similarly to genomes of other monocot crops as oil palm and banana, is quite unstable when cells pass through a cycle of tissue culture and regeneration. Changes in DNA sequences, translocation of DNA fragments and alteration of methylation patterns occur. Consequently, patterns of gene expression are changed, resulting in abnormal phenotypes. The data can be useful for future development of tools for early identification of off-type as well as for better understanding the phenomenon of somaclonal variation during propagation in vitro.