The Experts below are selected from a list of 216 Experts worldwide ranked by ideXlab platform
Joseph E. Munyaneza - One of the best experts on this subject based on the ideXlab platform.
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Phytoplasma diseases and insect vectors in potatoes of the Pacific northwest of the United States.
Bulletin of Insectology, 2020Co-Authors: Joseph E. Munyaneza, James M. CrosslinAbstract:Potato growers in the Columbia Basin of Washington and Oregon experienced an outbreak of the potato purple top disease in the 2002 growing season. This outbreak caused significant yield losses and reduced tuber quality. The disease was also observed during ensuing years, especially in potato fields not treated with insecticides. Using polymerase chain reaction, it was determined that the Beet Leafhopper-transmitted virescence agent (BLTVA) phytoplasma was the causal agent of the disease and that Circulifer tenellus was the major vector of the phytoplasma in this important potato growing region of the United States.
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Detection of Pathogens Associated with Psyllids and Leafhoppers in Capsicum annuum L. in the Mexican States of Durango, Zacatecas, and Michoacán
Plant Disease, 2017Co-Authors: K. D. Swisher, Joseph E. Munyaneza, R. Velásquez-valle, J. Mena-covarrubiasAbstract:In fall 2014, 5 to 75% percent of chili and bell pepper (Capsicum annuum L.) in commercial fields located in the Mexican states of Durango, Zacatecas, and Michoacan had symptoms of deformed, small, mosaic, curled, and chlorotic leaves; shortened internodes; plant dwarfing; or phyllody and rosetting leaf tips. At the same time, Leafhoppers and psyllids were observed in the fields, and more than 50 Beet Leafhoppers (Circulifer tenellus) and nearly 300 potato psyllids (Bactericera cockerelli) were collected from the pepper plants and adjacent weeds. Based on the insect pressure and observed symptoms, nearly 400 pepper samples were collected across this region of Mexico and tested for the presence of Leafhopper- and psyllid-associated pathogens. In all, 76% of the pepper samples were found to be infected with ‘Candidatus Liberibacter solanacearum’, Beet Leafhopper-transmitted virescence agent (BLTVA) phytoplasma, a strain of a curtovirus, or a combination of any two or three of these pathogens. Additionally, ...
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OCCURRENCE AND MOLECULAR DETECTION OF SPIROPLASMA CITRI IN CARROTS AND ITS INSECT VECTOR, CIRCULIFER TENELLUS, IN MEXICO
Journal of Plant Pathology, 2016Co-Authors: K. D. Swisher, R. Velásquez-valle, J. Mena-covarrubias, Joseph E. MunyanezaAbstract:In 2014, carrot plants in Zacatecas, Mexico, were found with yellow, brown, or purple-colored leaves, which were occasionally smaller and rolled. Roots of these affected plants were hairy, deformed, and small. Molecular diagnostics failed to detect phytoplasmas in these samples, but identified Spiroplasma citri in 58 and 94% of the samples using PCR targeting the spiralin and adhesion-related protein 1 (arp1) genes, respectively. Sequence analysis confirmed the presence of S. citri, and identified a novel, putative arp gene in one carrot sample. S. citri is a phytopathogenic mollicute transmitted by Leafhopper species. Beet Leafhoppers (Circulifer tenellus Baker) collected in the same state of Zacatecas, Mexico, were subsequently tested for S. citri infection, and 36.5% were positive using PCR targeting the arp1 gene. Sequencing analysis confirmed the presence of S. citri in the Leafhoppers. This is the first report of S. citri in carrot and C. tenellus in Mexico. Previously in the Americas, S. citri in carrot was only reported in Washington and California in the United States. The presence of S. citri in carrots and the Beet Leafhopper in Mexico, suggests that this pathogen could become a threat to vegetable industries in this region of Mexico, including the carrot industry.
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evaluation of Beet Leafhopper transmitted virescence agent damage in the columbia basin
American Journal of Potato Research, 2014Co-Authors: Alexzandra F Murphy, Jeremy L. Buchman, Silvia I Rondon, Ruben Marchosky, Joseph E. MunyanezaAbstract:Potato purple top disease is caused by a phytoplas- ma known as Beet Leafhopper Transmitted Virescence Agent (BLTVA), which is vectored by the Beet Leafhopper (BLH, Circulifer tenellus Baker). Previous studies determined that BLTVA can cause significant reductions in yield and tuber quality; however, quantifying the damage caused by BLTVA and the insect vector has been challenging. In 2009-2011, potato plants at different growth stages were exposed to vary- ing densities of BLH in a screen house located at the Hermiston Agricultural Research and Extension Center in Hermiston, OR. The densities of potentially infective BLH were one BLH per plant (low), two BLH per plant (medium), and five BLH per plant (high). Releases occurred at the following growth stages: vegetative, tuber initiation, tuber bulking, and maturation. The treatments were arranged in a randomized complete block design with three replications per treatment. Disease incidence was monitored weekly and yield was assessed. When all 3 years were combined, we found that increasing rates of disease incidence correlated with decreas- ing yields. We also found that greater yield losses were ob- served with later BLH release times. With both correlations, differences between years were a strong contributing factor. There was a mean decrease in yield of 0-12 % at a density of oneBLH per plant,6-19% attwoBLH per plant,and 6-20% for five BLH per plant. These general trends in yield loss suggest that economically relevant damage may occur at levelsas low as one or two potentially infective BLH per plant in the Columbia Basin.
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Susceptibility of Different Potato Plant Growth Stages to Purple Top Disease
American Journal of Potato Research, 2010Co-Authors: Joseph E. Munyaneza, Jeremy L. Buchman, James M. Crosslin, Venkatesan G. SengodaAbstract:Since 2002, potato growers in the Columbia Basin of Washington and Oregon have experienced outbreaks of potato purple top disease that have caused significant yield losses and reductions in tuber quality. It was determined that the Beet Leafhopper-transmitted virescence agent (BLTVA) phytoplasma is the causal agent of the disease in the Columbia Basin and that this pathogen is transmitted by the Beet Leafhopper. Little is known about the impact of purple top disease on potato in the Pacific Northwest and effective management strategies for the disease are lacking. Trials were conducted in 2006, 2007, and 2008 under laboratory and field conditions to assess susceptibility of different plant growth stages of selected potato cultivars to purple top. Ranger Russet and Umatilla Russet plants of different plant growth stages were exposed to BLTVA-infective Leafhoppers in the laboratory and transferred to outdoor field cages. In a second study, Ranger Russet, Umatilla Russet, Russet Burbank, and Russet Norkotah plants were exposed to naturally occurring BLTVA-infective Leafhoppers in the field by uncovering portions of caged rows of potatoes at desired intervals beginning at plant emergence. Plants were monitored for purple top symptoms and tested for BLTVA by PCR to confirm infection. Purple top foliar symptoms were observed in all the tested cultivars under both laboratory and field conditions. Results from both the laboratory and field experiments indicated that younger plants were more susceptible to purple top than older ones. In the laboratory trial, disease incidence was 87.5, 70, and 18.4% for Umatilla Russet, at 10 days, 25 days, and 50 days after plant emergence, respectively. Similarly, 65%, 52.3%, and 14.3% of the Ranger Russet plants became infected with purple top after being exposed to Beet Leafhoppers at 10 days, 25 days, and 50 days after emergence, respectively. In the field trial, disease incidence was relatively high in potato plants exposed to Leafhoppers during the first 5 weeks to 6 weeks after plant emergence and the infection declined thereafter. Statistical analysis of laboratory and field collected data indicated that there was a strong correlation between purple top infection and plant growth stage in all potato cultivars tested. Information from the present study will help potato growers prevent damage caused by purple top disease by appropriately protecting susceptible plant growth stages against the Beet Leafhopper. Desde 2002, los productores de papa de la rivera del Columbia de Washington y Oregon han experimentado el establecimiento de la enfermedad de la punta morada de la papa que ha causado significativas pérdidas en el rendimiento y reducciones en la calidad del tubérculo. Se determinó que el fitoplasma agente de la virescencia transmitido por la chicharrita de la remolacha (BLTVA) es el agente causal de la enfermedad en la rivera del Columbia y que este patógeno es transmitido por la chicharrita de la remolacha. Se sabe poco sobre el impacto de la enfermedad de la punta morada en papa en el Pacífico-Noroeste y se carece de estrategias efectivas para su manejo. Se establecieron ensayos en 2006, 2007 y 2008 bajo condiciones de laboratorio y de campo para analizar la susceptibilidad a la punta morada de los diferentes estados de crecimiento de la planta de cultivares selectos de papa. Plantas de Ranger Russet y Umatilla Russet en diferentes estados de crecimiento se expusieron a chicharritas infectivas con BLTVA en el laboratorio y se transfirieron en jaulas de campo al exterior. En un segundo estudio, plantas de Ranger Russet, Umatilla Russet, Russet Burbank, y Russet Norkotah se expusieron a la incidencia natural de chicharritas infectivas con BLTVA en el campo, mediante la remoción de partes de la cubierta de surcos de papa en túneles a intervalos controlados, empezando en la emergencia de las plantas. Se monitoreó a las plantas para los síntomas de la punta morada y se probaron para BLTVA con PCR para confirmar la infección. Se observaron síntomas foliares de la punta morada en todos los cultivares probados tanto en condiciones de laboratorio como de campo. Los resultados de los experimentos de ambos, laboratorio y campo, indicaron que las plantas jóvenes fueron más susceptibles a la punta morada que las mas viejas. En el ensayo del laboratorio la incidencia de la enfermedad fue 87.5, 70, y 18.4% para Umatilla Russet, a 10, 25, y 50 días después de la emergencia, respectivamente. Similarmente, 65, 52.3, y 14.3% de las plantas Ranger Russet se infectaron con punta morada después de ser expuestas a las chicharritas de la remolacha a los 10, 25 y 50 días de la emergencia, respectivamente. En el ensayo de campo, la incidencia de la enfermedad fue relativamente alta en plantas de papa expuestas a las chicharritas durante las primeras cinco a seis semanas después de la emergencia, y la infección declinó de ahí en adelante. Los análisis estadísticos de los datos colectados del laboratorio y campo indicaron que hubo una fuerte correlación entre la infección de la punta morada y el estado de crecimiento de la planta en todos los cultivares de papa probados. La información del presente estudio ayudará a los productores de papa a prevenir el daño causado por la enfermedad de la punta morada, mediante la protección apropiada contra la chicharrita de la remolacha en los estados de crecimiento susceptibles.
James M. Crosslin - One of the best experts on this subject based on the ideXlab platform.
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Phytoplasma diseases and insect vectors in potatoes of the Pacific northwest of the United States.
Bulletin of Insectology, 2020Co-Authors: Joseph E. Munyaneza, James M. CrosslinAbstract:Potato growers in the Columbia Basin of Washington and Oregon experienced an outbreak of the potato purple top disease in the 2002 growing season. This outbreak caused significant yield losses and reduced tuber quality. The disease was also observed during ensuing years, especially in potato fields not treated with insecticides. Using polymerase chain reaction, it was determined that the Beet Leafhopper-transmitted virescence agent (BLTVA) phytoplasma was the causal agent of the disease and that Circulifer tenellus was the major vector of the phytoplasma in this important potato growing region of the United States.
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Characterization of Beet curly top virus Strains Circulating in Beet Leafhoppers (Hemiptera: Cicadellidae) in Northeastern Oregon.
Plant Disease, 2016Co-Authors: Silvia I Rondon, Mary Sue Roster, Launa L. Hamlin, Kelsie J. Green, Alexander V. Karasev, James M. CrosslinAbstract:The Beet Leafhopper, Circulifer tenellus, is an agriculturally important pest, particularly in the western United States. This insect transmits the Beet curly top virus (BCTV) to multiple crops, including bean, tomato, and pepper. In this study, we investigated the incidence of BCTV in individual Leafhoppers collected at several sites in northeastern Oregon during the growing season in 2007, 2008, and 2009. Of the 800 insects tested, 151 (18.9%) were found positive for the virus. Percentage of virus incidence varied from 0% at one location in 2009 to a high of 55.6% for a location sampled in 2008. The complete virus genomes from one virus-positive insect collected in each of the 3 years were determined. BLAST analysis of the BCTV whole-genome sequences from 2007, 2008, and 2009 insects showed 98, 94, and 96% identities with the BCTV-Worland sequence (AY134867), respectively. The BCTV_2008 sequence showed the greatest identity (96%) with another BCTV genomic sequence (JN817383), and was found to be a recom...
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Susceptibility of Different Potato Plant Growth Stages to Purple Top Disease
American Journal of Potato Research, 2010Co-Authors: Joseph E. Munyaneza, Jeremy L. Buchman, James M. Crosslin, Venkatesan G. SengodaAbstract:Since 2002, potato growers in the Columbia Basin of Washington and Oregon have experienced outbreaks of potato purple top disease that have caused significant yield losses and reductions in tuber quality. It was determined that the Beet Leafhopper-transmitted virescence agent (BLTVA) phytoplasma is the causal agent of the disease in the Columbia Basin and that this pathogen is transmitted by the Beet Leafhopper. Little is known about the impact of purple top disease on potato in the Pacific Northwest and effective management strategies for the disease are lacking. Trials were conducted in 2006, 2007, and 2008 under laboratory and field conditions to assess susceptibility of different plant growth stages of selected potato cultivars to purple top. Ranger Russet and Umatilla Russet plants of different plant growth stages were exposed to BLTVA-infective Leafhoppers in the laboratory and transferred to outdoor field cages. In a second study, Ranger Russet, Umatilla Russet, Russet Burbank, and Russet Norkotah plants were exposed to naturally occurring BLTVA-infective Leafhoppers in the field by uncovering portions of caged rows of potatoes at desired intervals beginning at plant emergence. Plants were monitored for purple top symptoms and tested for BLTVA by PCR to confirm infection. Purple top foliar symptoms were observed in all the tested cultivars under both laboratory and field conditions. Results from both the laboratory and field experiments indicated that younger plants were more susceptible to purple top than older ones. In the laboratory trial, disease incidence was 87.5, 70, and 18.4% for Umatilla Russet, at 10 days, 25 days, and 50 days after plant emergence, respectively. Similarly, 65%, 52.3%, and 14.3% of the Ranger Russet plants became infected with purple top after being exposed to Beet Leafhoppers at 10 days, 25 days, and 50 days after emergence, respectively. In the field trial, disease incidence was relatively high in potato plants exposed to Leafhoppers during the first 5 weeks to 6 weeks after plant emergence and the infection declined thereafter. Statistical analysis of laboratory and field collected data indicated that there was a strong correlation between purple top infection and plant growth stage in all potato cultivars tested. Information from the present study will help potato growers prevent damage caused by purple top disease by appropriately protecting susceptible plant growth stages against the Beet Leafhopper. Desde 2002, los productores de papa de la rivera del Columbia de Washington y Oregon han experimentado el establecimiento de la enfermedad de la punta morada de la papa que ha causado significativas pérdidas en el rendimiento y reducciones en la calidad del tubérculo. Se determinó que el fitoplasma agente de la virescencia transmitido por la chicharrita de la remolacha (BLTVA) es el agente causal de la enfermedad en la rivera del Columbia y que este patógeno es transmitido por la chicharrita de la remolacha. Se sabe poco sobre el impacto de la enfermedad de la punta morada en papa en el Pacífico-Noroeste y se carece de estrategias efectivas para su manejo. Se establecieron ensayos en 2006, 2007 y 2008 bajo condiciones de laboratorio y de campo para analizar la susceptibilidad a la punta morada de los diferentes estados de crecimiento de la planta de cultivares selectos de papa. Plantas de Ranger Russet y Umatilla Russet en diferentes estados de crecimiento se expusieron a chicharritas infectivas con BLTVA en el laboratorio y se transfirieron en jaulas de campo al exterior. En un segundo estudio, plantas de Ranger Russet, Umatilla Russet, Russet Burbank, y Russet Norkotah se expusieron a la incidencia natural de chicharritas infectivas con BLTVA en el campo, mediante la remoción de partes de la cubierta de surcos de papa en túneles a intervalos controlados, empezando en la emergencia de las plantas. Se monitoreó a las plantas para los síntomas de la punta morada y se probaron para BLTVA con PCR para confirmar la infección. Se observaron síntomas foliares de la punta morada en todos los cultivares probados tanto en condiciones de laboratorio como de campo. Los resultados de los experimentos de ambos, laboratorio y campo, indicaron que las plantas jóvenes fueron más susceptibles a la punta morada que las mas viejas. En el ensayo del laboratorio la incidencia de la enfermedad fue 87.5, 70, y 18.4% para Umatilla Russet, a 10, 25, y 50 días después de la emergencia, respectivamente. Similarmente, 65, 52.3, y 14.3% de las plantas Ranger Russet se infectaron con punta morada después de ser expuestas a las chicharritas de la remolacha a los 10, 25 y 50 días de la emergencia, respectivamente. En el ensayo de campo, la incidencia de la enfermedad fue relativamente alta en plantas de papa expuestas a las chicharritas durante las primeras cinco a seis semanas después de la emergencia, y la infección declinó de ahí en adelante. Los análisis estadísticos de los datos colectados del laboratorio y campo indicaron que hubo una fuerte correlación entre la infección de la punta morada y el estado de crecimiento de la planta en todos los cultivares de papa probados. La información del presente estudio ayudará a los productores de papa a prevenir el daño causado por la enfermedad de la punta morada, mediante la protección apropiada contra la chicharrita de la remolacha en los estados de crecimiento susceptibles.
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incidence of the Beet Leafhopper transmitted virescence agent phytoplasma in local populations of the Beet Leafhopper circulifer tenellus in washington state
Journal of Insect Science, 2010Co-Authors: Joseph E. Munyaneza, James M. Crosslin, Jeffrey E Upton, Jeremy L. BuchmanAbstract:Phytoplasma diseases are increasingly becoming important in vegetable crops in the Pacific Northwest. Recently, growers in the Columbia Basin and Yakima Valley experienced serious outbreaks of potato purple top disease that caused significant yield loss and a reduction in tuber processing quality. It was determined that the Beet Leafhopper-transmitted virescence agent (BLTVA) phytoplasma was the causal agent of the disease in the area and that this pathogen was transmitted by the Beet Leafhopper, Circulifer tenellus Baker (Hemiptera: Cicadellidae). To provide the most effective management of phytoplasmas, timing of insecticide applications targeted against insects vectoring these pathogens should be correlated with both insect abundance and infectivity. Beet Leafhoppers were collected from a potato field and nearby weeds in Washington throughout the 2005, 2006, and 2007 growing seasons and tested for BLTVA by PCR to determine the incidence of this phytoplasma in the insects. In addition, overwintering Beet Leafhoppers were collected throughout Columbia Basin and Yakima Valley and tested for BLTVA to investigate if these insects might constitute a source of inoculum for this phytoplasma from one season to the next. Results showed that 29.6% of overwintering Leafhoppers collected near potato fields carried the phytoplasma. BLTVA-infected Leafhoppers were also found in both potatoes and nearby weedy habitats throughout the growing season. PCR testing indicated that a large proportion of Beet Leafhoppers invading potatoes were infected with the phytoplasma, with an average of 20.8, 34.8, and 9.2% in 2005, 2006, and 2007, respectively. Similarly, BLTVA infection rate in Leafhoppers collected from weeds in the vicinity of potatoes averaged 28.3, 24.5, and 5.6% in 2005, 2006, and 2007, respectively. Information from this study will help develop action thresholds for Beet Leafhopper control to reduce incidence of purple top disease in potatoes.
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Susceptibility of Different Potato Plant Growth Stages to Purple Top Disease
American Journal of Potato Research, 2009Co-Authors: Joseph E. Munyaneza, Jeremy L. Buchman, James M. Crosslin, Venkatesan G. SengodaAbstract:Since 2002, potato growers in the Columbia Basin of Washington and Oregon have experienced outbreaks of potato purple top disease that have caused significant yield losses and reductions in tuber quality. It was determined that the Beet Leafhopper-transmitted virescence agent (BLTVA) phytoplasma is the causal agent of the disease in the Columbia Basin and that this pathogen is transmitted by the Beet Leafhopper. Little is known about the impact of purple top disease on potato in the Pacific Northwest and effective management strategies for the disease are lacking. Trials were conducted in 2006, 2007, and 2008 under laboratory and field conditions to assess susceptibility of different plant growth stages of selected potato cultivars to purple top. Ranger Russet and Umatilla Russet plants of different plant growth stages were exposed to BLTVA-infective Leafhoppers in the laboratory and transferred to outdoor field cages. In a second study, Ranger Russet, Umatilla Russet, Russet Burbank, and Russet Norkotah plants were exposed to naturally occurring BLTVA-infective Leafhoppers in the field by uncovering portions of caged rows of potatoes at desired intervals beginning at plant emergence. Plants were monitored for purple top symptoms and tested for BLTVA by PCR to confirm infection. Purple top foliar symptoms were observed in all the tested cultivars under both laboratory and field conditions. Results from both the laboratory and field experiments indicated that younger plants were more susceptible to purple top than older ones. In the laboratory trial, disease incidence was 87.5, 70, and 18.4% for Umatilla Russet, at 10 days, 25 days, and 50 days after plant emergence, respectively. Similarly, 65%, 52.3%, and 14.3% of the Ranger Russet plants became infected with purple top after being exposed to Beet Leafhoppers at 10 days, 25 days, and 50 days after emergence, respectively. In the field trial, disease incidence was relatively high in potato plants exposed to Leafhoppers during the first 5 weeks to 6 weeks after plant emergence and the infection declined thereafter. Statistical analysis of laboratory and field collected data indicated that there was a strong correlation between purple top infection and plant growth stage in all potato cultivars tested. Information from the present study will help potato growers prevent damage caused by purple top disease by appropriately protecting susceptible plant growth stages against the Beet Leafhopper.
R L Gilbertson - One of the best experts on this subject based on the ideXlab platform.
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Genetic diversity in curtoviruses: a highly divergent strain of Beet mild curly top virus associated with an outbreak of curly top disease in pepper in Mexico
Archives of Virology, 2011Co-Authors: L.-f. Chen, E. Vivoda, R L GilbertsonAbstract:A full-length curtovirus genome was PCR-amplified and cloned from peppers in Mexico with symptoms of curly top disease. The cloned DNA of this isolate, MX-P24, replicated in Nicotiana tabacum protoplasts and was infectious in N. benthamiana plants. Sequence analysis revealed that the MX-P24 isolate had a typical curtovirus genome organization and was most similar to Beet mild curly top virus (BMCTV). However, sequence identities were at the threshold value for establishment of a new curtovirus species. To further investigate the biological properties of MX-P24, an agroinoculation system was generated. Agroinoculated shepherd’s purse plants developed typical curly top symptoms, and virus from these plants was transmissible by the Beet Leafhopper ( Circulifer tenellus ). The host range of MX-P24 was similar to that of BMCTV, with curly top symptoms induced in common bean, pepper, pumpkin, shepherd’s purse and tomato plants and mild or no symptoms induced in sugar Beet plants. Together, these results indicate that MX-P24 is a highly divergent strain of BMCTV associated with an outbreak of curly top disease in peppers in Mexico.
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identification of regions of the Beet mild curly top virus family geminiviridae capsid protein involved in systemic infection virion formation and Leafhopper transmission
Virology, 2005Co-Authors: Maria J Soto, Li-fang Chen, R L GilbertsonAbstract:Plant viruses in the genus Curtovirus (family Geminiviridae) are vectored by the Beet Leafhopper (Circulifer tenellus) and cause curly top disease in a wide range of dicotyledonous plants. An infectious clone of an isolate of Beet mild curly top virus (BMCTV-[W4]), associated with an outbreak of curly top in pepper and tomato crops, was characterized and used to investigate the role of the capsid protein (CP) in viral biology and pathogenesis. Frameshift mutations were introduced into the overlapping CP and V2 genes, and a series of CP alanine scanning mutations were generated. All mutants replicated in tobacco protoplasts or systemically infected plants, consistent with these gene products not being required for viral DNA replication. The CP frameshift mutant and most C-terminal alanine scanning mutants did not systemically infect Nicotiana benthamiana plants or form detectable virions, and were not Leafhopper-transmitted. In contrast, most N-terminal alanine scanning mutants systemically infected N. benthamiana and induced disease symptoms, formed virions and were Leafhopper-transmissible; thus, these substitution mutations did not significantly alter the functional properties of this region. One N-terminal mutant (CP49-51) systemically infected N. benthamiana, but did not form detectable virions; whereas another (CP25-28) systemically infected N. benthamiana and formed virions, but was not insect-transmissible. These mutants may reveal regions involved in virus movement through the plant and/or Leafhopper vector. Together, these results indicate an important role for virions in systemic infection (long-distance movement) and insect transmission, and strongly suggest that virions are the form in which BMCTV moves, long distance, in the phloem.
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distribution and rate of movement of the curtovirus Beet mild curly top virus family geminiviridae in the Beet Leafhopper
Phytopathology, 2003Co-Authors: Maria J Soto, R L GilbertsonAbstract:ABSTRACT A polymerase chain reaction (PCR)-based method for the detection of the curtovirus Beet mild curly top virus (BMCTV, previously named the Worland strain of Beet curly top virus) was developed and used to investigate the BMCTV-Beet Leafhopper interaction. Using PCR and a BMCTV-specific primer pair, an ≈1.1-kb BMCTV DNA fragment was amplified from adult Leafhoppers and from the organs involved in circulative transmission: the digestive tract, hemolymph, and salivary glands. The temporal distribution of BMCTV in the Leafhopper was determined using insects given acquisition access periods (AAPs) ranging from 1 to 48 h on BMCTV-infected shepherd's purse plants. BMCTV was detected in the digestive tract after all AAPs, in the hemolymph after AAPs of 3 h or greater, and in the salivary glands after AAPs of 4 h or greater. The amount of virus detected in the hemolymph and salivary glands increased with AAP length. The virus persisted for up to 30 days in Leafhoppers (given a 3-day AAP on BMCTV-infected p...
Jeremy L. Buchman - One of the best experts on this subject based on the ideXlab platform.
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evaluation of Beet Leafhopper transmitted virescence agent damage in the columbia basin
American Journal of Potato Research, 2014Co-Authors: Alexzandra F Murphy, Jeremy L. Buchman, Silvia I Rondon, Ruben Marchosky, Joseph E. MunyanezaAbstract:Potato purple top disease is caused by a phytoplas- ma known as Beet Leafhopper Transmitted Virescence Agent (BLTVA), which is vectored by the Beet Leafhopper (BLH, Circulifer tenellus Baker). Previous studies determined that BLTVA can cause significant reductions in yield and tuber quality; however, quantifying the damage caused by BLTVA and the insect vector has been challenging. In 2009-2011, potato plants at different growth stages were exposed to vary- ing densities of BLH in a screen house located at the Hermiston Agricultural Research and Extension Center in Hermiston, OR. The densities of potentially infective BLH were one BLH per plant (low), two BLH per plant (medium), and five BLH per plant (high). Releases occurred at the following growth stages: vegetative, tuber initiation, tuber bulking, and maturation. The treatments were arranged in a randomized complete block design with three replications per treatment. Disease incidence was monitored weekly and yield was assessed. When all 3 years were combined, we found that increasing rates of disease incidence correlated with decreas- ing yields. We also found that greater yield losses were ob- served with later BLH release times. With both correlations, differences between years were a strong contributing factor. There was a mean decrease in yield of 0-12 % at a density of oneBLH per plant,6-19% attwoBLH per plant,and 6-20% for five BLH per plant. These general trends in yield loss suggest that economically relevant damage may occur at levelsas low as one or two potentially infective BLH per plant in the Columbia Basin.
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Susceptibility of Different Potato Plant Growth Stages to Purple Top Disease
American Journal of Potato Research, 2010Co-Authors: Joseph E. Munyaneza, Jeremy L. Buchman, James M. Crosslin, Venkatesan G. SengodaAbstract:Since 2002, potato growers in the Columbia Basin of Washington and Oregon have experienced outbreaks of potato purple top disease that have caused significant yield losses and reductions in tuber quality. It was determined that the Beet Leafhopper-transmitted virescence agent (BLTVA) phytoplasma is the causal agent of the disease in the Columbia Basin and that this pathogen is transmitted by the Beet Leafhopper. Little is known about the impact of purple top disease on potato in the Pacific Northwest and effective management strategies for the disease are lacking. Trials were conducted in 2006, 2007, and 2008 under laboratory and field conditions to assess susceptibility of different plant growth stages of selected potato cultivars to purple top. Ranger Russet and Umatilla Russet plants of different plant growth stages were exposed to BLTVA-infective Leafhoppers in the laboratory and transferred to outdoor field cages. In a second study, Ranger Russet, Umatilla Russet, Russet Burbank, and Russet Norkotah plants were exposed to naturally occurring BLTVA-infective Leafhoppers in the field by uncovering portions of caged rows of potatoes at desired intervals beginning at plant emergence. Plants were monitored for purple top symptoms and tested for BLTVA by PCR to confirm infection. Purple top foliar symptoms were observed in all the tested cultivars under both laboratory and field conditions. Results from both the laboratory and field experiments indicated that younger plants were more susceptible to purple top than older ones. In the laboratory trial, disease incidence was 87.5, 70, and 18.4% for Umatilla Russet, at 10 days, 25 days, and 50 days after plant emergence, respectively. Similarly, 65%, 52.3%, and 14.3% of the Ranger Russet plants became infected with purple top after being exposed to Beet Leafhoppers at 10 days, 25 days, and 50 days after emergence, respectively. In the field trial, disease incidence was relatively high in potato plants exposed to Leafhoppers during the first 5 weeks to 6 weeks after plant emergence and the infection declined thereafter. Statistical analysis of laboratory and field collected data indicated that there was a strong correlation between purple top infection and plant growth stage in all potato cultivars tested. Information from the present study will help potato growers prevent damage caused by purple top disease by appropriately protecting susceptible plant growth stages against the Beet Leafhopper. Desde 2002, los productores de papa de la rivera del Columbia de Washington y Oregon han experimentado el establecimiento de la enfermedad de la punta morada de la papa que ha causado significativas pérdidas en el rendimiento y reducciones en la calidad del tubérculo. Se determinó que el fitoplasma agente de la virescencia transmitido por la chicharrita de la remolacha (BLTVA) es el agente causal de la enfermedad en la rivera del Columbia y que este patógeno es transmitido por la chicharrita de la remolacha. Se sabe poco sobre el impacto de la enfermedad de la punta morada en papa en el Pacífico-Noroeste y se carece de estrategias efectivas para su manejo. Se establecieron ensayos en 2006, 2007 y 2008 bajo condiciones de laboratorio y de campo para analizar la susceptibilidad a la punta morada de los diferentes estados de crecimiento de la planta de cultivares selectos de papa. Plantas de Ranger Russet y Umatilla Russet en diferentes estados de crecimiento se expusieron a chicharritas infectivas con BLTVA en el laboratorio y se transfirieron en jaulas de campo al exterior. En un segundo estudio, plantas de Ranger Russet, Umatilla Russet, Russet Burbank, y Russet Norkotah se expusieron a la incidencia natural de chicharritas infectivas con BLTVA en el campo, mediante la remoción de partes de la cubierta de surcos de papa en túneles a intervalos controlados, empezando en la emergencia de las plantas. Se monitoreó a las plantas para los síntomas de la punta morada y se probaron para BLTVA con PCR para confirmar la infección. Se observaron síntomas foliares de la punta morada en todos los cultivares probados tanto en condiciones de laboratorio como de campo. Los resultados de los experimentos de ambos, laboratorio y campo, indicaron que las plantas jóvenes fueron más susceptibles a la punta morada que las mas viejas. En el ensayo del laboratorio la incidencia de la enfermedad fue 87.5, 70, y 18.4% para Umatilla Russet, a 10, 25, y 50 días después de la emergencia, respectivamente. Similarmente, 65, 52.3, y 14.3% de las plantas Ranger Russet se infectaron con punta morada después de ser expuestas a las chicharritas de la remolacha a los 10, 25 y 50 días de la emergencia, respectivamente. En el ensayo de campo, la incidencia de la enfermedad fue relativamente alta en plantas de papa expuestas a las chicharritas durante las primeras cinco a seis semanas después de la emergencia, y la infección declinó de ahí en adelante. Los análisis estadísticos de los datos colectados del laboratorio y campo indicaron que hubo una fuerte correlación entre la infección de la punta morada y el estado de crecimiento de la planta en todos los cultivares de papa probados. La información del presente estudio ayudará a los productores de papa a prevenir el daño causado por la enfermedad de la punta morada, mediante la protección apropiada contra la chicharrita de la remolacha en los estados de crecimiento susceptibles.
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incidence of the Beet Leafhopper transmitted virescence agent phytoplasma in local populations of the Beet Leafhopper circulifer tenellus in washington state
Journal of Insect Science, 2010Co-Authors: Joseph E. Munyaneza, James M. Crosslin, Jeffrey E Upton, Jeremy L. BuchmanAbstract:Phytoplasma diseases are increasingly becoming important in vegetable crops in the Pacific Northwest. Recently, growers in the Columbia Basin and Yakima Valley experienced serious outbreaks of potato purple top disease that caused significant yield loss and a reduction in tuber processing quality. It was determined that the Beet Leafhopper-transmitted virescence agent (BLTVA) phytoplasma was the causal agent of the disease in the area and that this pathogen was transmitted by the Beet Leafhopper, Circulifer tenellus Baker (Hemiptera: Cicadellidae). To provide the most effective management of phytoplasmas, timing of insecticide applications targeted against insects vectoring these pathogens should be correlated with both insect abundance and infectivity. Beet Leafhoppers were collected from a potato field and nearby weeds in Washington throughout the 2005, 2006, and 2007 growing seasons and tested for BLTVA by PCR to determine the incidence of this phytoplasma in the insects. In addition, overwintering Beet Leafhoppers were collected throughout Columbia Basin and Yakima Valley and tested for BLTVA to investigate if these insects might constitute a source of inoculum for this phytoplasma from one season to the next. Results showed that 29.6% of overwintering Leafhoppers collected near potato fields carried the phytoplasma. BLTVA-infected Leafhoppers were also found in both potatoes and nearby weedy habitats throughout the growing season. PCR testing indicated that a large proportion of Beet Leafhoppers invading potatoes were infected with the phytoplasma, with an average of 20.8, 34.8, and 9.2% in 2005, 2006, and 2007, respectively. Similarly, BLTVA infection rate in Leafhoppers collected from weeds in the vicinity of potatoes averaged 28.3, 24.5, and 5.6% in 2005, 2006, and 2007, respectively. Information from this study will help develop action thresholds for Beet Leafhopper control to reduce incidence of purple top disease in potatoes.
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Susceptibility of Different Potato Plant Growth Stages to Purple Top Disease
American Journal of Potato Research, 2009Co-Authors: Joseph E. Munyaneza, Jeremy L. Buchman, James M. Crosslin, Venkatesan G. SengodaAbstract:Since 2002, potato growers in the Columbia Basin of Washington and Oregon have experienced outbreaks of potato purple top disease that have caused significant yield losses and reductions in tuber quality. It was determined that the Beet Leafhopper-transmitted virescence agent (BLTVA) phytoplasma is the causal agent of the disease in the Columbia Basin and that this pathogen is transmitted by the Beet Leafhopper. Little is known about the impact of purple top disease on potato in the Pacific Northwest and effective management strategies for the disease are lacking. Trials were conducted in 2006, 2007, and 2008 under laboratory and field conditions to assess susceptibility of different plant growth stages of selected potato cultivars to purple top. Ranger Russet and Umatilla Russet plants of different plant growth stages were exposed to BLTVA-infective Leafhoppers in the laboratory and transferred to outdoor field cages. In a second study, Ranger Russet, Umatilla Russet, Russet Burbank, and Russet Norkotah plants were exposed to naturally occurring BLTVA-infective Leafhoppers in the field by uncovering portions of caged rows of potatoes at desired intervals beginning at plant emergence. Plants were monitored for purple top symptoms and tested for BLTVA by PCR to confirm infection. Purple top foliar symptoms were observed in all the tested cultivars under both laboratory and field conditions. Results from both the laboratory and field experiments indicated that younger plants were more susceptible to purple top than older ones. In the laboratory trial, disease incidence was 87.5, 70, and 18.4% for Umatilla Russet, at 10 days, 25 days, and 50 days after plant emergence, respectively. Similarly, 65%, 52.3%, and 14.3% of the Ranger Russet plants became infected with purple top after being exposed to Beet Leafhoppers at 10 days, 25 days, and 50 days after emergence, respectively. In the field trial, disease incidence was relatively high in potato plants exposed to Leafhoppers during the first 5 weeks to 6 weeks after plant emergence and the infection declined thereafter. Statistical analysis of laboratory and field collected data indicated that there was a strong correlation between purple top infection and plant growth stage in all potato cultivars tested. Information from the present study will help potato growers prevent damage caused by purple top disease by appropriately protecting susceptible plant growth stages against the Beet Leafhopper.
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Susceptibility of Different Potato Cultivars to Purple Top Disease
American Journal of Potato Research, 2009Co-Authors: Joseph E. Munyaneza, James M. Crosslin, Jeremy L. BuchmanAbstract:In 2002, Columbia Basin potato growers in Washington and Oregon began to experience serious outbreaks of potato purple top disease that have caused significant yield losses and reductions in tuber quality. It was determined that the Beet Leafhopper-transmitted virescence agent (BLTVA) phytoplasma is the causal agent of the disease in the Columbia Basin and that this pathogen is transmitted by the Beet Leafhopper. Little is known about the impact of purple top disease on potato in the Pacific Northwest. Trials were conducted in 2006, 2007, and 2008 to assess susceptibility of important potato cultivars grown in the Columbia Basin to purple top under field conditions. Eight potato cultivars were planted in small field plots and exposed to naturally occurring BLTVA-infected Beet Leafhoppers. Disease incidence was recorded at the end of the growing season. Purple top foliar symptoms were observed in all the tested cultivars, and plant samples collected and tested by PCR confirmed the presence of BLTVA. Results also indicated significant differences in susceptibility of the cultivars to purple top. Disease incidence in Leafhopper-exposed plots ranged from 1.5 to 49.3% among cultivars. Russet Norkotah, Ranger Russet, and Umatilla Russet were relatively high in susceptibility to purple top, with average disease incidence of 33.5, 23.3, and 19.4%, respectively. Russet Burbank and FL1967 showed some resistance to purple top as they had the lowest plant disease incidence of 2.3 and 4.4%, respectively. Alturas, Shepody, and FL 1879 were moderately susceptible to purple top, with average disease incidence of 12.8, 8.0, and 9.3%, respectively. Information from this study will help potato growers reduce damage caused by potato purple top through selection of cultivars that are resistant to or tolerant of the disease and by protecting susceptible varieties against the Beet Leafhopper.
Jeffrey E Upton - One of the best experts on this subject based on the ideXlab platform.
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incidence of the Beet Leafhopper transmitted virescence agent phytoplasma in local populations of the Beet Leafhopper circulifer tenellus in washington state
Journal of Insect Science, 2010Co-Authors: Joseph E. Munyaneza, James M. Crosslin, Jeffrey E Upton, Jeremy L. BuchmanAbstract:Phytoplasma diseases are increasingly becoming important in vegetable crops in the Pacific Northwest. Recently, growers in the Columbia Basin and Yakima Valley experienced serious outbreaks of potato purple top disease that caused significant yield loss and a reduction in tuber processing quality. It was determined that the Beet Leafhopper-transmitted virescence agent (BLTVA) phytoplasma was the causal agent of the disease in the area and that this pathogen was transmitted by the Beet Leafhopper, Circulifer tenellus Baker (Hemiptera: Cicadellidae). To provide the most effective management of phytoplasmas, timing of insecticide applications targeted against insects vectoring these pathogens should be correlated with both insect abundance and infectivity. Beet Leafhoppers were collected from a potato field and nearby weeds in Washington throughout the 2005, 2006, and 2007 growing seasons and tested for BLTVA by PCR to determine the incidence of this phytoplasma in the insects. In addition, overwintering Beet Leafhoppers were collected throughout Columbia Basin and Yakima Valley and tested for BLTVA to investigate if these insects might constitute a source of inoculum for this phytoplasma from one season to the next. Results showed that 29.6% of overwintering Leafhoppers collected near potato fields carried the phytoplasma. BLTVA-infected Leafhoppers were also found in both potatoes and nearby weedy habitats throughout the growing season. PCR testing indicated that a large proportion of Beet Leafhoppers invading potatoes were infected with the phytoplasma, with an average of 20.8, 34.8, and 9.2% in 2005, 2006, and 2007, respectively. Similarly, BLTVA infection rate in Leafhoppers collected from weeds in the vicinity of potatoes averaged 28.3, 24.5, and 5.6% in 2005, 2006, and 2007, respectively. Information from this study will help develop action thresholds for Beet Leafhopper control to reduce incidence of purple top disease in potatoes.
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seasonal occurrence and abundance of Beet Leafhopper in the potato growing region of washington and oregon columbia basin and yakima valley
American Journal of Potato Research, 2008Co-Authors: Joseph E. Munyaneza, P B Hamm, Andrew S Jensen, Jeffrey E UptonAbstract:Leafhopper-transmitted phytoplasma diseases are increasingly becoming important in the Pacific Northwest. An epidemic of purple top disease of potato (Solanum tuberosum L.) occurred in the Columbia Basin of Washington and Oregon in the 2002 growing season and caused significant yield losses to potato fields and a reduction in tuber quality. The disease was also observed during ensuing years, especially in potato fields not treated with insecticides. In 2003, 2004, and 2005, Leafhopper sampling was conducted in the Columbia Basin of Washington and Oregon and Yakima Valley to determine the seasonal occurrence and abundance of the Beet Leafhopper, Circulifer tenellus Baker, the primary vector of the potato purple top disease phytoplasma in this major potato producing region of the USA. Leafhoppers were sampled using sweep nets and yellow sticky traps at weekly intervals around potato fields throughout the Columbia Basin and in Yakima Valley from April to October. Leafhoppers were also sampled in two experimental potato fields not treated with insecticides in both 2003 and 2004. Leafhoppers in the samples were sorted, identified, and counted. The Beet Leafhopper was common and abundant in weeds near potato fields from mid-April to mid-October and had at least three generations per year. The Beet Leafhopper appeared into potato fields as early as April, but generally arrived in early May, and was present in potatoes throughout the remainder of the growing season. This Leafhopper was abundant in potatoes in May to early July, suggesting that potatoes more likely are infected with the purple top disease phytoplasma during early summer; however, it is not clear how far into the growing season potato infection occurs. Several other Leafhopper species were abundant in the study area and included economically important species such as Macrosteles spp., Ceratagallia spp., and Colladonus spp. All the Leafhopper species found in weeds in the vicinity of potatoes were also present within potato fields. Further studies of the role C. tenellus and other potential Leafhopper vectors play in purple top will be needed to improve management of this disease in the Pacific Northwest.
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Seasonal Occurrence and Abundance of Beet Leafhopper in the Potato Growing Region of Washington and Oregon Columbia Basin and Yakima Valley
American Journal of Potato Research, 2008Co-Authors: Joseph E. Munyaneza, Andrew S Jensen, Philip B. Hamm, Jeffrey E UptonAbstract:La enfermedad fitoplásmica transmitida por una cigarrita se está convirtiendo en muy importante en el Pacífico Noroeste. La enfermedad epidémica conocida como punta morada de la papa ( Solanum tuberosum L.) se presentó en la Cuenca Columbia de Washington y Oregon en la campaña del 2002 y causó pérdidas significativas de rendimiento en los campos de papa y reducción de la calidad del tubérculo. La enfermedad también fue observada en los años siguientes, especialmente en los campos de papa no tratados con insecticida. En 2003, 2004 y 2005, el muestreo de cigarritas se realizó en la Cuenca Columbia de Washington y Oregón y en el Valle de Yakima para determinar la presencia estacional y abundancia de cigarritas de la remolacha, Circulifer tenellus Baker, el principal vector de punta morada de la papa en esta importante región de producción de papa de los Estados Unidos. Las cigarritas se muestrearon usando mallas y trampas amarillas a intervalos semanales por toda la Cuenca Columbia y el Valle de Yakima de Abril a Octubre. Las cigarritas también se muestrearon en dos campos experimentales sin tratar con insecticidas en 2003 y 2004. Las cigarritas fueron ordenadas, identificadas y contadas. Las cigarritas de la remolacha estuvieron presentes y en abundancia en malezas cerca de los campos de papa desde mediados de Abril a mediados de Octubre y tuvieron por lo menos tres generaciones al año. Las cigarritas de la remolacha aparecieron en los campos de papa en Abril, pero generalmente llegaron a principios de Mayo y estuvieron presentes en papa por todo lo que quedó de la campaña. Estas cigarritas fueron abundantes en papa en Mayo hasta principios de Julio, sugiriendo que las papas se infectarán con el fitoplasma de la punta morada a principios del verano, sin embargo, no está claro cuando se realiza la infección durante la etapa del cultivo. Estuvieron presentes en el área de estudio muchas otras especies de cigarritas incluyendo especies económicamente importantes como Macrosteles spp., Ceratagallia spp., y Colladonus spp. Todas las especies de cigarritas encontradas en malezas en la vecindad, estuvieron también presentes dentro de los campos de papa. Para mejorar el manejo de esta enfermedad en el Pacífico Noroeste se necesitarán estudios adicionales del rol que juegan C. tenellus y otras cigarritas, potenciales vectores de la punta morada. Leafhopper-transmitted phytoplasma diseases are increasingly becoming important in the Pacific Northwest. An epidemic of purple top disease of potato ( Solanum tuberosum L.) occurred in the Columbia Basin of Washington and Oregon in the 2002 growing season and caused significant yield losses to potato fields and a reduction in tuber quality. The disease was also observed during ensuing years, especially in potato fields not treated with insecticides. In 2003, 2004, and 2005, Leafhopper sampling was conducted in the Columbia Basin of Washington and Oregon and Yakima Valley to determine the seasonal occurrence and abundance of the Beet Leafhopper, Circulifer tenellus Baker, the primary vector of the potato purple top disease phytoplasma in this major potato producing region of the USA. Leafhoppers were sampled using sweep nets and yellow sticky traps at weekly intervals around potato fields throughout the Columbia Basin and in Yakima Valley from April to October. Leafhoppers were also sampled in two experimental potato fields not treated with insecticides in both 2003 and 2004. Leafhoppers in the samples were sorted, identified, and counted. The Beet Leafhopper was common and abundant in weeds near potato fields from mid-April to mid-October and had at least three generations per year. The Beet Leafhopper appeared into potato fields as early as April, but generally arrived in early May, and was present in potatoes throughout the remainder of the growing season. This Leafhopper was abundant in potatoes in May to early July, suggesting that potatoes more likely are infected with the purple top disease phytoplasma during early summer; however, it is not clear how far into the growing season potato infection occurs. Several other Leafhopper species were abundant in the study area and included economically important species such as Macrosteles spp., Ceratagallia spp., and Colladonus spp. All the Leafhopper species found in weeds in the vicinity of potatoes were also present within potato fields. Further studies of the role C. tenellus and other potential Leafhopper vectors play in purple top will be needed to improve management of this disease in the Pacific Northwest.
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Beet Leafhopper hemiptera cicadellidae transmits the columbia basin potato purple top phytoplasma to potatoes Beets and weeds
Journal of Economic Entomology, 2006Co-Authors: Joseph E. Munyaneza, James M. Crosslin, Jeffrey E UptonAbstract:Experiments were conducted to determine whether the Beet Leafhopper, Circulifer tenellus (Baker) (Hemiptera: Cicadellidae), transmits the purple top phytoplasma to potato, Solanum tuberosum L.; Beets, Beta vulgaris L.; and selected weed hosts. The Beet Leafhopper-transmitted virescence agent (BLTVA) phytoplasma was identified as the causal agent of the potato purple top disease outbreaks that recently occurred in the Columbia Basin of Washington and Oregon. The phytoplasma previously was found to be associated almost exclusively with the Beet Leafhopper, suggesting that this insect is the probable vector of BLTVA in this important potato-growing region. Eight potato cultivars, including ‘Russet Burbank’, ‘Ranger Russet’, ‘Shepody’, ‘Umatilla Russet’, ‘Atlantic’, ‘FL-1879’, ‘FL-1867’, and ‘FL-1833’, were exposed for a week to BLTVA-infected Beet Leafhoppers. After exposure, the plants were maintained outdoors in large cages and then tested for BLTVA by using polymerase chain reaction after 6 to 7 wk. The Leafhoppers transmitted BLTVA to seven of the eight exposed potato cultivars. Sixty-four percent of the exposed plants tested positive for the phytoplasma. In addition, 81% of the BLTVA-infected potato plants developed distinct potato purple top disease symptoms. Beet Leafhoppers also transmitted BLTVA to Beets and several weeds, including groundsel, Senecio vulgaris L.; shepherd’s purse, Capsella bursa-pastoris (L.) Medik); kochia, Kochia scoparia (L.) Schrad; and Russian thistle, Salsola kali L. This is the first report of transmission of BLTVA to potatoes, Beets, and the above-mentioned four weed species. Results of the current study prove that the Beet Leafhopper is a vector of the potato purple top disease.
