The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Themis J. Michailides - One of the best experts on this subject based on the ideXlab platform.
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limited evidence for accumulation of latent infections of canker causing pathogens in shoots of stone fruit and Nut Crops in california
Phytopathology, 2021Co-Authors: Yong Luo, Dan Felts, Franz J A Niederholzer, Danielle Lightle, John R Lake, Themis J. MichailidesAbstract:Prevalence of latent infections of the canker-causing fungi Botryosphaeria dothidea and species of Cytospora, Diplodia, Lasiodiplodia, Neofusicoccum, and Phomopsis in young shoots of almond, prune and walNut trees in California was studied to test the hypotheses that 1) latent infections accumulate from current-season shoots to 1-year-old shoots in the orchard and 2) there are distinct associations among pathogen taxa present as latent infections in the same shoot. Samples of newly-emerged and 1-year-old shoots were periodically collected in each almond, prune, and walNut orchard for two growing seasons. A real-time quantitative PCR assay was used to quantify latent infection with three parameters: incidence, molecular severity and latent infection index. Diplodia spp. were absent from most samples. For almond, Lasiodiplodia spp. and Cytospora spp. were detected with a maximum incidence >90%, while B. dothidea and Neofusicoccumspp. incidence was 50% in most cases, while those of Cytospora spp. and Lasiodiplodia spp. were 30 - 60% and 30 - 100%, respectively. For walNut, many samplings showed higher incidence in 1-year-old (30 - 80%) than in newly-emerged shoots (10 - 50%). Accumulation of latent infection between the two shoot age classes was detected in only few cases. The percentages of samples showing coexistence of two, three and four pathogen taxa in the same shoot were 20 - 25%, <10% and <5%, respectively. Pairwise associations among pathogen taxa in the same shoot were significant in many cases.
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understanding the process of latent infection of canker causing pathogens in stone fruit and Nut Crops in california
Plant Disease, 2019Co-Authors: Yong Luo, Dan Felts, Paulo S F Lichtemberg, Franz J A Niederholzer, Danielle Lightle, Themis J. MichailidesAbstract:The Botryosphaeriaceae family is considered a fungal family that includes pathogens causing latent infection of woody plants, and a number of species were identified as causal pathogens of canker and shoot blight diseases. To better understand the process of latent infection of major canker-causing pathogens in woody tissues in different tree Crops important in California, shoot and bud samples were randomly collected from four tree Crops: almond, dried plum, pistachio, and walNut. The previously developed DNA primers and quantitative real-time PCR (qPCR) assay systems were applied to detect six canker-causing pathogen groups, including Botryosphaeria dothidea, and species of Cytospora, Diplodia, Lasiodiplodia, Neofusicoccum, and Phomopsis. The concepts of molecular severity (MS) and latent infection index (LII) were introduced and applied to quantify the latent infection levels for these samples. Variation in incidence of latent infection among pathogen groups was observed, whereas the incidences were relatively low among species of Phomopsis and Diplodia. High incidences of Cytospora spp. were observed in two dried plum (prune) orchards. Most orchards showed high incidences of B. dothidea and Lasiodiplodia spp. and moderate incidences of Neofusicoccum spp. Variations in MS were observed among samples of the studied orchards, ranging from 4 to 8. The overall results of LII demonstrated that species of Diplodia and Phomopsis were less important in population development of canker-causing pathogens at the latent phase. Lasiodiplodia spp. were the most aggressive and had been well developed in populations among the studied tree Crops. Cytospora spp. became predominant in two of the three dried plum orchards, whereas B. dothidea and Neofusicoccum spp. showed trends of increase in incidence across various tree Crops. This study also demonstrated the usefulness of this sensitive qPCR approach in providing evidence of the latent phase of major canker-causing pathogens of stone fruit and Nut Crops at an early stage of latent infection in woody plant tissues.
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Ecology and Epidemiology of Diseases of Nut Crops and Olives Caused by Botryosphaeriaceae Fungi in California and Spain.
Plant disease, 2019Co-Authors: Juan Moral, David P. Morgan, Antonio Trapero, Themis J. MichailidesAbstract:In recent decades, the cultivated area and production of Nuts and olives have increased, driven by an increasing consumer interest in healthier food. Diseases of almond, pistachio, olive, and walNut Crops caused by species belonging to the Botryosphaeriaceae family have caused concern worldwide. Although considerable progress has been made in elucidating the etiology of these diseases, scientific knowledge of other aspects of these diseases is more limited. In this article, we present an overview of the most important diseases caused by Botryosphaeriaceae fungi affecting almond, pistachio, olive, and walNut Crops by focusing on ecology and epidemiology, primarily in California and Spain.
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Management of Botryosphaeria canker and blight diseases of temperate zone Nut Crops
Crop Protection, 2019Co-Authors: Juan Moral, David P. Morgan, Themis J. MichailidesAbstract:Abstract Species of Botryosphaeriaceae family cause detrimental damage and yield losses in perennial Crops. In California, Botryosphaeriaceae species cause three major diseases, the panicle and shoot blight of pistachio; the canker, dieback, and blight of walNut; and, the band canker of almond. The control of Botryosphaeria diseases of pistachio and walNut by applying synthetic fungicides has been an effective management strategy. Conversely, because the unique disease cycle of almond band canker, attacking the almond trunk through the growth cracks, fungicide applications are not recommended for controlling this disease after expression of symptoms. Whatever the disease, integrating the different management practices, such as cultural practices, plant resistance, or biological control, is a necessity. Here, we review the available management strategies that can be used by pest control advisers and farmers of Nut Crops in order to control these important diseases.
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molecular phylogeny of cytospora species associated with canker diseases of fruit and Nut Crops in california with the descriptions of ten new species and one new combination
IMA Fungus, 2018Co-Authors: Daniel P. Lawrence, Themis J. Michailides, M. T. Nouri, L A Holland, Renaud Travadon, Ara Abramians, Florent P. TrouillasAbstract:Cytospora species are destructive canker and dieback pathogens of woody hosts in natural and agroecosystems around the world. In this genus, molecular identification has been limited due to the paucity of multi-locus sequence typing studies and the lack of sequence data from type specimens in public repositories, stalling robust phylogenetic reconstructions. In most cases a morphological species concept could not be applied due to the plasticity of characters and significant overlap of morphological features such as spore dimensions and fruiting body characters. In this study, we employed a molecular phylogenetic framework with the inclusion of four nuclear loci (ITS, translation elongation factor 1-alpha, actin, and beta-tubulin) to unveil the biodiversity and taxonomy of this understudied important genus of plant pathogens. Phylogenetic inferences based on 150 Californian isolates revealed 15 Cytospora species associated with branch and twig cankers and dieback of almond, apricot, cherry, cottonwood, olive, peach, pistachio, plum, pomegranate, and walNut trees in California. Of the 15 species recovered in this study, 10 are newly described and typified, in addition to one new combination. The pathogenic status of the newly described Cytospora species requires further investigation as most species were associated with severe dieback and decline of diverse and economically important fruit and Nut Crops in California.
Gerrit Hoogenboom - One of the best experts on this subject based on the ideXlab platform.
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Remote Sensing and Geospatial Technological Applications for Site-specific Management of Fruit and Nut Crops: A Review
Remote Sensing, 2010Co-Authors: Sudhanshu S. Panda, Gerrit HoogenboomAbstract:Site-specific crop management (SSCM) is one facet of precision agriculture which is helping increase production with minimal input. It has enhanced the cost-benefit scenario in crop production. Even though the SSCM is very widely used in row crop agriculture like corn, wheat, rice, soybean, etc. it has very little application in cash Crops like fruit and Nut. The main goal of this review paper was to conduct a comprehensive review of advanced technologies, including geospatial technologies, used in site-specific management of fruit and Nut Crops. The review explores various remote sensing data from different platforms like satellite, LIDAR, aerial, and field imaging. The study analyzes the use of satellite sensors, such as Quickbird, Landsat, SPOT, and IRS imagery as well as hyperspectral narrow-band remote sensing data in study of fruit and Nut Crops in blueberry, citrus, peach, apple, etc. The study also explores other geospatial technologies such as GPS, GIS spatial modeling, advanced image processing techniques, and information technology for suitability study, orchard delineation, and classification accuracy assessment. The study also provides an example of a geospatial model developed in ArcGIS ModelBuilder to automate the blueberry production suitability analysis. The GIS spatial model is developed using various crop characteristics such as chilling hours, soil permeability, drainage, and pH, and land cover to determine the best sites for growing
Yong Luo - One of the best experts on this subject based on the ideXlab platform.
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limited evidence for accumulation of latent infections of canker causing pathogens in shoots of stone fruit and Nut Crops in california
Phytopathology, 2021Co-Authors: Yong Luo, Dan Felts, Franz J A Niederholzer, Danielle Lightle, John R Lake, Themis J. MichailidesAbstract:Prevalence of latent infections of the canker-causing fungi Botryosphaeria dothidea and species of Cytospora, Diplodia, Lasiodiplodia, Neofusicoccum, and Phomopsis in young shoots of almond, prune and walNut trees in California was studied to test the hypotheses that 1) latent infections accumulate from current-season shoots to 1-year-old shoots in the orchard and 2) there are distinct associations among pathogen taxa present as latent infections in the same shoot. Samples of newly-emerged and 1-year-old shoots were periodically collected in each almond, prune, and walNut orchard for two growing seasons. A real-time quantitative PCR assay was used to quantify latent infection with three parameters: incidence, molecular severity and latent infection index. Diplodia spp. were absent from most samples. For almond, Lasiodiplodia spp. and Cytospora spp. were detected with a maximum incidence >90%, while B. dothidea and Neofusicoccumspp. incidence was 50% in most cases, while those of Cytospora spp. and Lasiodiplodia spp. were 30 - 60% and 30 - 100%, respectively. For walNut, many samplings showed higher incidence in 1-year-old (30 - 80%) than in newly-emerged shoots (10 - 50%). Accumulation of latent infection between the two shoot age classes was detected in only few cases. The percentages of samples showing coexistence of two, three and four pathogen taxa in the same shoot were 20 - 25%, <10% and <5%, respectively. Pairwise associations among pathogen taxa in the same shoot were significant in many cases.
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understanding the process of latent infection of canker causing pathogens in stone fruit and Nut Crops in california
Plant Disease, 2019Co-Authors: Yong Luo, Dan Felts, Paulo S F Lichtemberg, Franz J A Niederholzer, Danielle Lightle, Themis J. MichailidesAbstract:The Botryosphaeriaceae family is considered a fungal family that includes pathogens causing latent infection of woody plants, and a number of species were identified as causal pathogens of canker and shoot blight diseases. To better understand the process of latent infection of major canker-causing pathogens in woody tissues in different tree Crops important in California, shoot and bud samples were randomly collected from four tree Crops: almond, dried plum, pistachio, and walNut. The previously developed DNA primers and quantitative real-time PCR (qPCR) assay systems were applied to detect six canker-causing pathogen groups, including Botryosphaeria dothidea, and species of Cytospora, Diplodia, Lasiodiplodia, Neofusicoccum, and Phomopsis. The concepts of molecular severity (MS) and latent infection index (LII) were introduced and applied to quantify the latent infection levels for these samples. Variation in incidence of latent infection among pathogen groups was observed, whereas the incidences were relatively low among species of Phomopsis and Diplodia. High incidences of Cytospora spp. were observed in two dried plum (prune) orchards. Most orchards showed high incidences of B. dothidea and Lasiodiplodia spp. and moderate incidences of Neofusicoccum spp. Variations in MS were observed among samples of the studied orchards, ranging from 4 to 8. The overall results of LII demonstrated that species of Diplodia and Phomopsis were less important in population development of canker-causing pathogens at the latent phase. Lasiodiplodia spp. were the most aggressive and had been well developed in populations among the studied tree Crops. Cytospora spp. became predominant in two of the three dried plum orchards, whereas B. dothidea and Neofusicoccum spp. showed trends of increase in incidence across various tree Crops. This study also demonstrated the usefulness of this sensitive qPCR approach in providing evidence of the latent phase of major canker-causing pathogens of stone fruit and Nut Crops at an early stage of latent infection in woody plant tissues.
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Development of qPCR systems to quantify shoot infections by canker-causing pathogens in stone fruits and Nut Crops.
Journal of applied microbiology, 2016Co-Authors: Yong Luo, Dan Felts, Ryan D. Puckett, D.p. Morgan, Themis J. MichailidesAbstract:Aims To develop real-time PCR assays for quantification of shoot infection levels of canker disease of stone fruits and Nut Crops caused by six fungal pathogen groups. Methods and Results This study focused on six major canker-causing fungal pathogen groups: Phomopsis spp., Botryosphaeria dothidea, Lasiodiplodia spp., Cytospora spp., Neofusicoccum spp., and Diplodia spp., occurring in stone fruits and Nut Crops in California. DNA primers were designed to specifically target each of the six pathogen groups after the specificity tests using canker-causing and non-canker-causing pathogens and by using DNA sequences of other species from GenBank using BLAST. The quantitative real-time PCR (qPCR) systems were developed and used to quantify the infection levels of inoculated dried plum shoots. Conclusions For Neofusicoccum spp. and Phomopsis spp., which were used in inoculation of walNut shoots, the values of the molecular severity ranged from 5.60 to 6.94 during the 16 days of latent infection period. The qPCR assays were more efficient, accurate and precise to quantify latent infections caused by canker-causing pathogens as compared to the traditional plating methods. Significance and Impact of the Study This study demonstrated the potential of using the developed qPCR systems for epidemiological studies on canker diseases of woody plants. This article is protected by copyright. All rights reserved.
Sudhanshu S. Panda - One of the best experts on this subject based on the ideXlab platform.
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Remote Sensing and Geospatial Technological Applications for Site-specific Management of Fruit and Nut Crops: A Review
Remote Sensing, 2010Co-Authors: Sudhanshu S. Panda, Gerrit HoogenboomAbstract:Site-specific crop management (SSCM) is one facet of precision agriculture which is helping increase production with minimal input. It has enhanced the cost-benefit scenario in crop production. Even though the SSCM is very widely used in row crop agriculture like corn, wheat, rice, soybean, etc. it has very little application in cash Crops like fruit and Nut. The main goal of this review paper was to conduct a comprehensive review of advanced technologies, including geospatial technologies, used in site-specific management of fruit and Nut Crops. The review explores various remote sensing data from different platforms like satellite, LIDAR, aerial, and field imaging. The study analyzes the use of satellite sensors, such as Quickbird, Landsat, SPOT, and IRS imagery as well as hyperspectral narrow-band remote sensing data in study of fruit and Nut Crops in blueberry, citrus, peach, apple, etc. The study also explores other geospatial technologies such as GPS, GIS spatial modeling, advanced image processing techniques, and information technology for suitability study, orchard delineation, and classification accuracy assessment. The study also provides an example of a geospatial model developed in ArcGIS ModelBuilder to automate the blueberry production suitability analysis. The GIS spatial model is developed using various crop characteristics such as chilling hours, soil permeability, drainage, and pH, and land cover to determine the best sites for growing
Dan Felts - One of the best experts on this subject based on the ideXlab platform.
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limited evidence for accumulation of latent infections of canker causing pathogens in shoots of stone fruit and Nut Crops in california
Phytopathology, 2021Co-Authors: Yong Luo, Dan Felts, Franz J A Niederholzer, Danielle Lightle, John R Lake, Themis J. MichailidesAbstract:Prevalence of latent infections of the canker-causing fungi Botryosphaeria dothidea and species of Cytospora, Diplodia, Lasiodiplodia, Neofusicoccum, and Phomopsis in young shoots of almond, prune and walNut trees in California was studied to test the hypotheses that 1) latent infections accumulate from current-season shoots to 1-year-old shoots in the orchard and 2) there are distinct associations among pathogen taxa present as latent infections in the same shoot. Samples of newly-emerged and 1-year-old shoots were periodically collected in each almond, prune, and walNut orchard for two growing seasons. A real-time quantitative PCR assay was used to quantify latent infection with three parameters: incidence, molecular severity and latent infection index. Diplodia spp. were absent from most samples. For almond, Lasiodiplodia spp. and Cytospora spp. were detected with a maximum incidence >90%, while B. dothidea and Neofusicoccumspp. incidence was 50% in most cases, while those of Cytospora spp. and Lasiodiplodia spp. were 30 - 60% and 30 - 100%, respectively. For walNut, many samplings showed higher incidence in 1-year-old (30 - 80%) than in newly-emerged shoots (10 - 50%). Accumulation of latent infection between the two shoot age classes was detected in only few cases. The percentages of samples showing coexistence of two, three and four pathogen taxa in the same shoot were 20 - 25%, <10% and <5%, respectively. Pairwise associations among pathogen taxa in the same shoot were significant in many cases.
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understanding the process of latent infection of canker causing pathogens in stone fruit and Nut Crops in california
Plant Disease, 2019Co-Authors: Yong Luo, Dan Felts, Paulo S F Lichtemberg, Franz J A Niederholzer, Danielle Lightle, Themis J. MichailidesAbstract:The Botryosphaeriaceae family is considered a fungal family that includes pathogens causing latent infection of woody plants, and a number of species were identified as causal pathogens of canker and shoot blight diseases. To better understand the process of latent infection of major canker-causing pathogens in woody tissues in different tree Crops important in California, shoot and bud samples were randomly collected from four tree Crops: almond, dried plum, pistachio, and walNut. The previously developed DNA primers and quantitative real-time PCR (qPCR) assay systems were applied to detect six canker-causing pathogen groups, including Botryosphaeria dothidea, and species of Cytospora, Diplodia, Lasiodiplodia, Neofusicoccum, and Phomopsis. The concepts of molecular severity (MS) and latent infection index (LII) were introduced and applied to quantify the latent infection levels for these samples. Variation in incidence of latent infection among pathogen groups was observed, whereas the incidences were relatively low among species of Phomopsis and Diplodia. High incidences of Cytospora spp. were observed in two dried plum (prune) orchards. Most orchards showed high incidences of B. dothidea and Lasiodiplodia spp. and moderate incidences of Neofusicoccum spp. Variations in MS were observed among samples of the studied orchards, ranging from 4 to 8. The overall results of LII demonstrated that species of Diplodia and Phomopsis were less important in population development of canker-causing pathogens at the latent phase. Lasiodiplodia spp. were the most aggressive and had been well developed in populations among the studied tree Crops. Cytospora spp. became predominant in two of the three dried plum orchards, whereas B. dothidea and Neofusicoccum spp. showed trends of increase in incidence across various tree Crops. This study also demonstrated the usefulness of this sensitive qPCR approach in providing evidence of the latent phase of major canker-causing pathogens of stone fruit and Nut Crops at an early stage of latent infection in woody plant tissues.
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Development of qPCR systems to quantify shoot infections by canker-causing pathogens in stone fruits and Nut Crops.
Journal of applied microbiology, 2016Co-Authors: Yong Luo, Dan Felts, Ryan D. Puckett, D.p. Morgan, Themis J. MichailidesAbstract:Aims To develop real-time PCR assays for quantification of shoot infection levels of canker disease of stone fruits and Nut Crops caused by six fungal pathogen groups. Methods and Results This study focused on six major canker-causing fungal pathogen groups: Phomopsis spp., Botryosphaeria dothidea, Lasiodiplodia spp., Cytospora spp., Neofusicoccum spp., and Diplodia spp., occurring in stone fruits and Nut Crops in California. DNA primers were designed to specifically target each of the six pathogen groups after the specificity tests using canker-causing and non-canker-causing pathogens and by using DNA sequences of other species from GenBank using BLAST. The quantitative real-time PCR (qPCR) systems were developed and used to quantify the infection levels of inoculated dried plum shoots. Conclusions For Neofusicoccum spp. and Phomopsis spp., which were used in inoculation of walNut shoots, the values of the molecular severity ranged from 5.60 to 6.94 during the 16 days of latent infection period. The qPCR assays were more efficient, accurate and precise to quantify latent infections caused by canker-causing pathogens as compared to the traditional plating methods. Significance and Impact of the Study This study demonstrated the potential of using the developed qPCR systems for epidemiological studies on canker diseases of woody plants. This article is protected by copyright. All rights reserved.
