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J. V. Herrmann - One of the best experts on this subject based on the ideXlab platform.
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A long-term study on the population dynamics of the grape Leafhopper (Empoasca vitis) and antagonistic mymarid species
Journal of Pest Science, 2004Co-Authors: Susanne Boll, J. V. HerrmannAbstract:The population dynamics of the grape Leafhopper ( Empoasca vitis ) and its egg parasitoids (Mymaridae) were studied at five representative sites in the Franconian wine-growing region from 1998 to 2001. In contrast to other German wine-growing areas, only one generation of grape Leafhoppers per season was observed. In general, irrespective of the application of insecticides, the peak density of the first generation was much lower than that of immigrating grape Leafhoppers. As the observed mymarid:Leafhopper ratios (1:0.8–1:4.8) of the first generation were extremely high, egg parasitoids might be effectively controlling the grape Leafhopper in Franconian vineyards. Slightly elevated Leafhopper densities at the end of the growing season were caused by migrating sister species. Intervention thresholds were rarely reached; however, stress symptoms as discoloured intercostal leaf areas or rolled leaf edges were widespread. Over the whole study period three mymarid species occurred at all monitoring sites: Anagrus atomus, Stethynium triclavatum and a species, not previously reported in the German wine-growing region, Anagrus avalae . The dominance relationships of these species were site-specific, differing more strongly between than within sites; however, differences could not be related to the kind of management or natural surrounding of the vineyards. A hatching experiment confirmed the biological significance of A . avalae as an effective antagonist.
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A long-term study on the population dynamics of the grape Leafhopper (Empoasca vitis) and antagonistic mymarid species
Journal of Pest Science, 2004Co-Authors: Susanne Boll, J. V. HerrmannAbstract:The population dynamics of the grape Leafhopper ( Empoasca vitis ) and its egg parasitoids (Mymaridae) were studied at five representative sites in the Franconian wine-growing region from 1998 to 2001. In contrast to other German wine-growing areas, only one generation of grape Leafhoppers per season was observed. In general, irrespective of the application of insecticides, the peak density of the first generation was much lower than that of immigrating grape Leafhoppers. As the observed mymarid:Leafhopper ratios (1:0.8–1:4.8) of the first generation were extremely high, egg parasitoids might be effectively controlling the grape Leafhopper in Franconian vineyards. Slightly elevated Leafhopper densities at the end of the growing season were caused by migrating sister species. Intervention thresholds were rarely reached; however, stress symptoms as discoloured intercostal leaf areas or rolled leaf edges were widespread. Over the whole study period three mymarid species occurred at all monitoring sites: Anagrus atomus, Stethynium triclavatum and a species, not previously reported in the German wine-growing region, Anagrus avalae . The dominance relationships of these species were site-specific, differing more strongly between than within sites; however, differences could not be related to the kind of management or natural surrounding of the vineyards. A hatching experiment confirmed the biological significance of A . avalae as an effective antagonist.
Saskia A. Hogenhout - One of the best experts on this subject based on the ideXlab platform.
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Spiroplasma-like organisms closely associated with the gut in five Leafhopper species (Hemiptera: Cicadellidae)
Archives of Microbiology, 2011Co-Authors: El-desouky Ammar, Gail E. Gasparich, David G. Hall, Saskia A. HogenhoutAbstract:Spiroplasmas are bacteria in the Class Mollicutes that are frequently associated with insects and/or plants. Here, we describe the ultrastructure, localization, and occurrence of apparent commensal/symbiotic spiroplasma-like organisms (SLOs) in the midgut and hindgut of five Leafhopper species from laboratory-reared colonies. Those found in Dalbulus elimatus, Endria inimica , and Macrosteles quadrilineatus were long and tubular shaped, whereas those in Dalbulus maidis and Graminella nigrifrons were shorter and mostly rod-shaped in their host organisms. These SLOs were found in great numbers in the gut lumen frequently associated with the gut microvilli, but unlike the plant-pathogenic mollicutes, they did not seem to invade the gut epithelium or other tissues in any of these five Leafhopper species. Large accumulations of these gut-associated organisms were more commonly found by confocal laser scanning microscopy in males than in females and in crowded than in singly reared Leafhoppers. Ultrastructural evidence suggests that these SLOs may be horizontally transmitted between Leafhoppers by contamination of the mouth parts with Leafhopper excretions.
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Plant host range and Leafhopper transmission of maize fine streak virus.
Phytopathology®, 2010Co-Authors: Jane Todd, Margaret G. Redinbaugh, El-desouky Ammar, Casey W. Hoy, Saskia A. HogenhoutAbstract:Maize fine streak virus (MFSV), an emerging Rhabdovirus sp. in the genus Nucleorhabdovirus, is persistently transmitted by the black-faced Leafhopper, Graminella nigrifrons (Forbes). MFSV was transmitted to maize, wheat, oat, rye, barley, foxtail, annual ryegrass, and quackgrass by G. nigrifrons. Parameters affecting efficiency of MFSV acquisition (infection) and transmission (inoculation) to maize were evaluated using single-Leafhopper inoculations and enzyme-linked immunosorbent assay. MFSV was detected in ≈20% of Leafhoppers that fed on infected plants but
Joseph E. Munyaneza - One of the best experts on this subject based on the ideXlab platform.
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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: Kylie D. Swisher, R. Velásquez-valle, Joseph E. Munyaneza, 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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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, Jeffrey E Upton, James M. Crosslin, 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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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.
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beet Leafhopper hemiptera cicadellidae settling behavior survival and reproduction on selected host plants
Journal of Economic Entomology, 2005Co-Authors: Joseph E. Munyaneza, J. UptonAbstract:Experiments were conducted to determine the settling behavior, survival, and reproduction of the beet Leafhopper, Circulifer tenellus (Baker), when maintained on selected host plants. This Leafhopper was recently identified in the Columbia Basin of Washington and Oregon as the probable vector of the beet Leafhopper-transmitted virescence agent phytoplasma, causal agent of several vegetable crop diseases, including potato purple top. Plants selected for study were sugar beet, Beta vulgaris L.; radish, Raphanus sativus L.; dry bean, Phaseolus vulgaris L.; potato, Solanum tuberosum L.; carrot, Daucus carota L.; and tomato, Lycopersicon esculentum Mill. Leafhopper adults were confined on caged plants, and settling behavior was observed during a 72-h period and survival was monitored for 40 d. Also, oviposition and nymphal production were investigated by maintaining Leafhoppers for ≈90 d on each of the selected plants. Sixty to 100% of Leafhoppers settled on all studied plants during the first 5 h, but settling on bean and tomato declined sharply thereafter. Leafhopper mortality was very high on bean and tomato, with 95 and 65% of the Leafhoppers, respectively, dying in about a week. In contrast, 77, 90, and 95% of Leafhoppers maintained on potato, sugar beet, and radish, respectively, survived until the end of the 40-d experimental period. Beet Leafhopper oviposition and nymphal production and development only occurred on sugar beet, radish, and potato; reproduction was lower on potato.
D. C. Opgenorth - One of the best experts on this subject based on the ideXlab platform.
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Overwintering of Corn Leafhopper, Dalbulus maidis (Homoptera: Cicadellidae), and Spiroplasma kunkelii (Mycoplasmatales: Spiroplasmataceae) in California’s San Joaquin Valley
Environmental Entomology, 2004Co-Authors: Charles G. Summers, Albert S. Newton, D. C. OpgenorthAbstract:Abstract A 3-yr study was conducted in California’s southern San Joaquin Valley to determine the overwintering survival of the corn Leafhopper, Dalbulus maidis (DeLong and Wolcott), and the mollicute, Spiroplasma kunkelii, the causal agent of corn stunt disease. Corn Leafhopper populations were sampled from November to March using yellow sticky cards, D-vac suction samples, and inspection of volunteer corn plants and spring planted corn. S. kunkelii presence was determined by sampling sentinel plants placed in the field during the winter, Leafhoppers collected throughout the winter, and evaluation of volunteer plants over the winter and spring planted corn. Leafhoppers were collected on yellow sticky cards throughout the winter during all 3 yr. They were also regularly recovered from alfalfa, Medicago sativa L., winter forage (wheat, Triticum aestivum L., and triticale, Triticale hexaploide Lart. and riparian areas by D-vac suction sampling. Females constituted the majority of Leafhoppers (>80%) recovered...
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overwintering of corn Leafhopper dalbulus maidis homoptera cicadellidae and spiroplasma kunkelii mycoplasmatales spiroplasmataceae in california s san joaquin valley
Environmental Entomology, 2004Co-Authors: Charles G. Summers, Albert S. Newton, D. C. OpgenorthAbstract:Abstract A 3-yr study was conducted in California’s southern San Joaquin Valley to determine the overwintering survival of the corn Leafhopper, Dalbulus maidis (DeLong and Wolcott), and the mollicute, Spiroplasma kunkelii, the causal agent of corn stunt disease. Corn Leafhopper populations were sampled from November to March using yellow sticky cards, D-vac suction samples, and inspection of volunteer corn plants and spring planted corn. S. kunkelii presence was determined by sampling sentinel plants placed in the field during the winter, Leafhoppers collected throughout the winter, and evaluation of volunteer plants over the winter and spring planted corn. Leafhoppers were collected on yellow sticky cards throughout the winter during all 3 yr. They were also regularly recovered from alfalfa, Medicago sativa L., winter forage (wheat, Triticum aestivum L., and triticale, Triticale hexaploide Lart. and riparian areas by D-vac suction sampling. Females constituted the majority of Leafhoppers (>80%) recovered...
Susanne Boll - One of the best experts on this subject based on the ideXlab platform.
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A long-term study on the population dynamics of the grape Leafhopper (Empoasca vitis) and antagonistic mymarid species
Journal of Pest Science, 2004Co-Authors: Susanne Boll, J. V. HerrmannAbstract:The population dynamics of the grape Leafhopper ( Empoasca vitis ) and its egg parasitoids (Mymaridae) were studied at five representative sites in the Franconian wine-growing region from 1998 to 2001. In contrast to other German wine-growing areas, only one generation of grape Leafhoppers per season was observed. In general, irrespective of the application of insecticides, the peak density of the first generation was much lower than that of immigrating grape Leafhoppers. As the observed mymarid:Leafhopper ratios (1:0.8–1:4.8) of the first generation were extremely high, egg parasitoids might be effectively controlling the grape Leafhopper in Franconian vineyards. Slightly elevated Leafhopper densities at the end of the growing season were caused by migrating sister species. Intervention thresholds were rarely reached; however, stress symptoms as discoloured intercostal leaf areas or rolled leaf edges were widespread. Over the whole study period three mymarid species occurred at all monitoring sites: Anagrus atomus, Stethynium triclavatum and a species, not previously reported in the German wine-growing region, Anagrus avalae . The dominance relationships of these species were site-specific, differing more strongly between than within sites; however, differences could not be related to the kind of management or natural surrounding of the vineyards. A hatching experiment confirmed the biological significance of A . avalae as an effective antagonist.
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A long-term study on the population dynamics of the grape Leafhopper (Empoasca vitis) and antagonistic mymarid species
Journal of Pest Science, 2004Co-Authors: Susanne Boll, J. V. HerrmannAbstract:The population dynamics of the grape Leafhopper ( Empoasca vitis ) and its egg parasitoids (Mymaridae) were studied at five representative sites in the Franconian wine-growing region from 1998 to 2001. In contrast to other German wine-growing areas, only one generation of grape Leafhoppers per season was observed. In general, irrespective of the application of insecticides, the peak density of the first generation was much lower than that of immigrating grape Leafhoppers. As the observed mymarid:Leafhopper ratios (1:0.8–1:4.8) of the first generation were extremely high, egg parasitoids might be effectively controlling the grape Leafhopper in Franconian vineyards. Slightly elevated Leafhopper densities at the end of the growing season were caused by migrating sister species. Intervention thresholds were rarely reached; however, stress symptoms as discoloured intercostal leaf areas or rolled leaf edges were widespread. Over the whole study period three mymarid species occurred at all monitoring sites: Anagrus atomus, Stethynium triclavatum and a species, not previously reported in the German wine-growing region, Anagrus avalae . The dominance relationships of these species were site-specific, differing more strongly between than within sites; however, differences could not be related to the kind of management or natural surrounding of the vineyards. A hatching experiment confirmed the biological significance of A . avalae as an effective antagonist.
