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G S Abawi - One of the best experts on this subject based on the ideXlab platform.
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An on-farm bioassay for assessing Meloidogyne Hapla infestations as a decision management tool
Crop Protection, 2008Co-Authors: Beth K. Gugino, John Ludwig, G S AbawiAbstract:Abstract A simple, visual soil bioassay was developed to assess Meloidogyne Hapla soil infestation levels in order to facilitate the implementation of management practices on an as-needed basis. Generally, four composite soil samples were collected per target field, planted with lettuce (Lactuca sativa) seedlings and maintained in a greenhouse for this study. After 4–6 weeks, the root systems were washed free of soil and scored for root-galling severity by counting the total number of galls that developed or estimating the percentage of root system galled. Crop-specific thresholds or the presence or absence of galls are then used in part to make M. Hapla management decisions. This bioassay was simplified and adapted for on-farm use by growers and has already been successfully utilized in making nematode management decisions.
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Damage and Management of Meloidogyne Hapla Using Oxamyl on Carrot in New York.
Journal of nematology, 2006Co-Authors: Beth K. Gugino, G S Abawi, John LudwigAbstract:The northern root-knot nematode (Meloidogyne Hapla) is a major pathogen of processing carrot in New York, significantly reducing marketable yield and profitability. Severely infected carrots are stubby, galled and forked and therefore unmarketable. In field microplot trials in 1996 and 1998, the incidence and severity of root-galling increased and the marketable yield of carrot decreased as the initial inoculum density of M. Hapla was increased from 0 to 8 eggs/cm(3) soil, in mineral or organic soils. The application of oxamyl at planting was effective against M. Hapla and its damage to carrots grown in mineral and organic soils. Oxamyl application reduced root-galling severity and increased marketable yield. In commercial fields, the cost-effectiveness of oxamyl application was related to the level of soil infestation with M. Hapla.
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monoxenic maintenance and reproduction of root knot nematode Meloidogyne Hapla on multiple species in vitro root culture systems
Plant Cell Reports, 2002Co-Authors: N. A. Mitkowski, G S AbawiAbstract:The ability of tomato root tips transformed with Agrobacterium rhizogenes and non-transformed onion and dandelion root tips to regenerate and provide suitable monoxenic hosts for the maintenance of root-knot nematode (Meloidogyne Hapla) was investigated. Populations of M. Hapla were successfully established on all root culture systems examined, but the onion root culture was overall the most effective method for long-term maintenance and reproduction of M. Hapla. The use of a pre-induction medium containing the hormone α-naphthaleneacetic acid was necessary for the production of onion root culture systems but was not required for the establishment of tomato or dandelion root cultures. Differences in nematode reproduction were observed on tomato when multiple populations of M. Hapla were used for inoculations.
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Fungi Parasitic on Juveniles and Egg Masses of Meloidogyne Hapla in Organic Soils from New York
Journal of Nematology, 1998Co-Authors: N M Viaene, G S AbawiAbstract:Fungi associated with egg masses and juveniles of Meloidogyne Hapla were isolated from organic soil samples obtained from five fields planted to lettuce or onion in NewYork. The soil samples were placed in sterilized clay pots, infested with M. Hapla, and planted to lettuce. After 4 months, egg masses and juveniles were surface-disinfested, plated on water agar, and examined for fungal infection. Depending on the soil sample, fungal isolates were recovered from 13% to 30%, and from 5% to 24% of the egg masses and juveniles, respectively. A total of 24 and 16 isolates collected from egg masses and juveniles, respectively, were selected for further characterization. Fifteen of the isolates were considered as egg-mass pathogens as they were able to infect healthy assay egg masses and could be succesfully reisolated. These fungi included species of Fusarium, Alternatia, and Verticillium psalliotae. Six of the egg-mass-parasitizing fungi could not be identified. Nine fungal isolates were found to be pathogenic to juveniles of M. Hapla; six were identified as Monacrosporium sp., two as Arthrobotrys sp., and one as Hirsutella rhossiliensis. The remaining 16 fungal isolates were unable to infect egg masses or juveniles, and thus were considered nonparasitic to M. Hapla. Key words: Alternaria, antagonist, Arthrobotrys, biological control, Fusarium, Hirsutella, Meloidogyne Hapla, Monacrosporium, nematode, nematophagous fungus, northern root-knot nematode, Verticillium.
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Damage Threshold of Meloidogyne Hapla to Lettuce in Organic Soil
Journal of nematology, 1996Co-Authors: N M Viaene, G S AbawiAbstract:Lettuce was seeded in pots in the greenhouse and in field microplots in 1991 and 1992. Pots and microplots were filled with untreated or fumigated organic soil infested with Meloidogyne Hapla at seven initial population densities (Pi) (0 to 32 eggs/cm³ soil). Lettuce weight, severity of root galling, and number of eggs per root system (Pf) were determined after 8 weeks. At the highest Pi, M. Hapla caused yield losses up to 64% in the microplots and plant death in the greenhouse tests. The Seinhorst equation was used to describe the relation between lettuce weight and Pi (r² = 0.73 - 0.98) and to calculate the damage threshold density (T). Values of T were 7 and 8 eggs/cm³ soil in the greenhouse tests of 1991 and 1992, respectively. In the microplot tests, T was 1 egg/cm³ soil in 1991 and 2 eggs/cm³ soil in 1992. The damage threshold was the same in untreated and fumigated soils. At low Pi, root galling was more severe in the pots than in the microplots. Pf increased with increasing Pi of M. Hapla in both tests, but declined at Pi T in the greenhouse tests. The reproduction rate (Pf/Pi) of M. Hapla was highest at the lowest Pi. Key words: damage threshold, Lactuca sativa, lettuce, Meloidogyne Hapla, nematode, northern rootknot nematode, organic soil, population dynamics, yield loss.
Don B. Hayden - One of the best experts on this subject based on the ideXlab platform.
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THE INFLUENCE OF SOIL AMENDMENTS (FLY ASH AND STABILIZED BIOSOLIDS) ON Meloidogyne Hapla IN MICROPLOTS PLANTED WITH TOMATO ( LYCOPERSICON ESCULENTUM ) [LA INFLUENCIA DE ENMIENDAS DE SUELO (CENIZA VOLANTE Y BIOSÓLIDOS ESTABILIZADOS) SOBRE Meloidogyne
Nematropica, 2011Co-Authors: Pablo F. Jaramillo-lópez, Michael Powell, Don B. HaydenAbstract:Jaramillo-Lopez, P. F., M. A. Powell, and D. B. Hayden. 2011. The influence of soil amendments (fly ash and stabilized biosolids) on Meloidogyne Hapla in microplots planted with tomato (Lycopersicon esculentum). Nematropica 41:141- 149. The use of amendments composed of fly ash and stabilized biosolids were evaluated for managing Meloidogyne Hapla on tomato (Lycopersicon esculentum P. Mill.). Amendment ratios of biosolids and fly ash were established based on international guidelines and previous studies for the use of biosolids and fly ash in soils. The field trial included amendments of 3%, 6%, 9%, 12%, and 15% (w/w) of biosolids and 3%, 6%, 9%, 12%, and 15% w/w) of a 50:50 mixture of fly ash and biosolids. Changes in parameters that might affect nematode viability were monitored including electrical conductivity, pH, biocontrol agents (bacterial and fungal colony forming units), and plant yield. Tomato plants grown with amendments showed improved yields relative to controls in the presence of nematode infestation. None of the amendments altered EC, pH or CFU enough to impact nematode populations. Jaramillo-Lopez, P. F., M. A. Powell, and D. B. Hayden. 2011. La influencia de enmiendas de suelo (ceniza volante y biosolidos estabilizados) sobre Meloidogyne Hapla en microparcelas plantadas con tomate (Lycopersicon esculentum). Nematropica 41:141-149. El uso de enmiendas de suelo compuestas por ceniza volante de carbon mineral y biosolidos estabilizados fue evaluado para manejar Meloidogyne Hapla en tomate (Lycopersicon esculentum P. Mill.). Las tasas de aplicacion de biosolidos y ceniza volante fueron establecidas segun normativas internacionales para el uso de ceniza y biosolidos en suelo. El experimento en campo incluyo enmiendas del 3%, 6%, 9%, 12%, y 15% en peso de biosolidos y 3%, 6%, 9%, 12%, y 15% en peso de una mezcla de 50:50 de ceniza y biosolidos. Los cambios en los parametros que pueden afectar la viabilidad de los nematodos fue monitoreada incluyendo conductividad electrica, pH, agentes de biocontrol (unidades formadoras de colonia de hongos y bacterias), y rendimiento de las plantas. Las plantas de tomate que crecieron en las enmiendas mostraron un incremento en rendimiento inclusive con infestacion de nematodos al compararlos con los controles. Ninguna de las enmiendas altero la conductividad, pH, o las unidades formadoras de colonias lo suficiente como para causar un impacto sobre las poblaciones de nematodos.
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RESEARCH NOTE/NOTA INVESTIGATIVA THE INFLUENCE OF SOIL AMENDMENTS (FLY ASH AND STABILIZED BIOSOLIDS) ON Meloidogyne Hapla IN MICROPLOTS PLANTED WITH TOMATO (LYCOPERSICON ESCULENTUM)
2011Co-Authors: Pablo F. Jaramillo-lópez, Michael Powell, Don B. HaydenAbstract:Jaramillo-Lopez, P. F., M. A. Powell, and D. B. Hayden. 2011. The influence of soil amendments (fly ash and stabilized biosolids) on Meloidogyne Hapla in microplots planted with tomato (Lycopersicon esculentum). Nematropica 41:141149. The use of amendments composed of fly ash and stabilized biosolids were evaluated for managing Meloidogyne Hapla on tomato (Lycopersicon esculentum P. Mill.). Amendment ratios of biosolids and fly ash were established based on international guidelines and previous studies for the use of biosolids and fly ash in soils. The field trial included amendments of 3%, 6%, 9%, 12%, and 15% (w/w) of biosolids and 3%, 6%, 9%, 12%, and 15% w/w) of a 50:50 mixture of fly ash and biosolids. Changes in parameters that might affect nematode viability were monitored including electrical conductivity, pH, biocontrol agents (bacterial and fungal colony forming units), and plant yield. Tomato plants grown with amendments showed improved yields relative to controls in the presence of nematode infestation. None of the amendments altered EC, pH or CFU enough to impact nematode populations.
N. A. Mitkowski - One of the best experts on this subject based on the ideXlab platform.
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Reproductive fitness on lettuce of populations of Meloidogyne Hapla from New York State vegetable fields
Nematology, 2003Co-Authors: N. A. Mitkowski, George S. AbawiAbstract:Six New York State populations of Meloidogyne Hapla differed in their reproductive fitness and severity of galling induced on lettuce (Lactuca sativa) cvs Ithaca, Salinas, and Montello and the breeding line 41-595. Both lettuce germplasm and nematode population had a significant effect on reproductive fitness and the interaction between germplasm and population was also significant. Differences in the number of nematodes recovered per g of root was attributable to differences in numbers of eggs per egg mass. Results suggested that there are separate genetic factors controlling reproduction and galling on lettuce. Based on this study, it would be prudent to include multiple, local populations of M. Hapla in future resistance germplasm screening tests.
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monoxenic maintenance and reproduction of root knot nematode Meloidogyne Hapla on multiple species in vitro root culture systems
Plant Cell Reports, 2002Co-Authors: N. A. Mitkowski, G S AbawiAbstract:The ability of tomato root tips transformed with Agrobacterium rhizogenes and non-transformed onion and dandelion root tips to regenerate and provide suitable monoxenic hosts for the maintenance of root-knot nematode (Meloidogyne Hapla) was investigated. Populations of M. Hapla were successfully established on all root culture systems examined, but the onion root culture was overall the most effective method for long-term maintenance and reproduction of M. Hapla. The use of a pre-induction medium containing the hormone α-naphthaleneacetic acid was necessary for the production of onion root culture systems but was not required for the establishment of tomato or dandelion root cultures. Differences in nematode reproduction were observed on tomato when multiple populations of M. Hapla were used for inoculations.
Pablo F. Jaramillo-lópez - One of the best experts on this subject based on the ideXlab platform.
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THE INFLUENCE OF SOIL AMENDMENTS (FLY ASH AND STABILIZED BIOSOLIDS) ON Meloidogyne Hapla IN MICROPLOTS PLANTED WITH TOMATO ( LYCOPERSICON ESCULENTUM ) [LA INFLUENCIA DE ENMIENDAS DE SUELO (CENIZA VOLANTE Y BIOSÓLIDOS ESTABILIZADOS) SOBRE Meloidogyne
Nematropica, 2011Co-Authors: Pablo F. Jaramillo-lópez, Michael Powell, Don B. HaydenAbstract:Jaramillo-Lopez, P. F., M. A. Powell, and D. B. Hayden. 2011. The influence of soil amendments (fly ash and stabilized biosolids) on Meloidogyne Hapla in microplots planted with tomato (Lycopersicon esculentum). Nematropica 41:141- 149. The use of amendments composed of fly ash and stabilized biosolids were evaluated for managing Meloidogyne Hapla on tomato (Lycopersicon esculentum P. Mill.). Amendment ratios of biosolids and fly ash were established based on international guidelines and previous studies for the use of biosolids and fly ash in soils. The field trial included amendments of 3%, 6%, 9%, 12%, and 15% (w/w) of biosolids and 3%, 6%, 9%, 12%, and 15% w/w) of a 50:50 mixture of fly ash and biosolids. Changes in parameters that might affect nematode viability were monitored including electrical conductivity, pH, biocontrol agents (bacterial and fungal colony forming units), and plant yield. Tomato plants grown with amendments showed improved yields relative to controls in the presence of nematode infestation. None of the amendments altered EC, pH or CFU enough to impact nematode populations. Jaramillo-Lopez, P. F., M. A. Powell, and D. B. Hayden. 2011. La influencia de enmiendas de suelo (ceniza volante y biosolidos estabilizados) sobre Meloidogyne Hapla en microparcelas plantadas con tomate (Lycopersicon esculentum). Nematropica 41:141-149. El uso de enmiendas de suelo compuestas por ceniza volante de carbon mineral y biosolidos estabilizados fue evaluado para manejar Meloidogyne Hapla en tomate (Lycopersicon esculentum P. Mill.). Las tasas de aplicacion de biosolidos y ceniza volante fueron establecidas segun normativas internacionales para el uso de ceniza y biosolidos en suelo. El experimento en campo incluyo enmiendas del 3%, 6%, 9%, 12%, y 15% en peso de biosolidos y 3%, 6%, 9%, 12%, y 15% en peso de una mezcla de 50:50 de ceniza y biosolidos. Los cambios en los parametros que pueden afectar la viabilidad de los nematodos fue monitoreada incluyendo conductividad electrica, pH, agentes de biocontrol (unidades formadoras de colonia de hongos y bacterias), y rendimiento de las plantas. Las plantas de tomate que crecieron en las enmiendas mostraron un incremento en rendimiento inclusive con infestacion de nematodos al compararlos con los controles. Ninguna de las enmiendas altero la conductividad, pH, o las unidades formadoras de colonias lo suficiente como para causar un impacto sobre las poblaciones de nematodos.
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RESEARCH NOTE/NOTA INVESTIGATIVA THE INFLUENCE OF SOIL AMENDMENTS (FLY ASH AND STABILIZED BIOSOLIDS) ON Meloidogyne Hapla IN MICROPLOTS PLANTED WITH TOMATO (LYCOPERSICON ESCULENTUM)
2011Co-Authors: Pablo F. Jaramillo-lópez, Michael Powell, Don B. HaydenAbstract:Jaramillo-Lopez, P. F., M. A. Powell, and D. B. Hayden. 2011. The influence of soil amendments (fly ash and stabilized biosolids) on Meloidogyne Hapla in microplots planted with tomato (Lycopersicon esculentum). Nematropica 41:141149. The use of amendments composed of fly ash and stabilized biosolids were evaluated for managing Meloidogyne Hapla on tomato (Lycopersicon esculentum P. Mill.). Amendment ratios of biosolids and fly ash were established based on international guidelines and previous studies for the use of biosolids and fly ash in soils. The field trial included amendments of 3%, 6%, 9%, 12%, and 15% (w/w) of biosolids and 3%, 6%, 9%, 12%, and 15% w/w) of a 50:50 mixture of fly ash and biosolids. Changes in parameters that might affect nematode viability were monitored including electrical conductivity, pH, biocontrol agents (bacterial and fungal colony forming units), and plant yield. Tomato plants grown with amendments showed improved yields relative to controls in the presence of nematode infestation. None of the amendments altered EC, pH or CFU enough to impact nematode populations.
G. D. Griffin - One of the best experts on this subject based on the ideXlab platform.
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Biological Relationship of Meloidogyne Hapla Populations to Alfalfa Cultivars.
Journal of nematology, 1995Co-Authors: G. D. Griffin, F. A. GrayAbstract:Greenhouse and growth chamber studies were established to determine if there are pathological and physiological differences among Meloidogyne Hapla populations from California (CA), Nevada (NV), Utah (UT), and Wyoming (WY) on alfalfa cultivars classified as resistant or susceptible to root-knot nematodes. In the greenhouse, plant survival was not consistent with resistance classifications. While all highly resistant Nevada Synthetic germplasm (Nev Syn XX) plants survived inoculation with all nematode populations, two cultivars classified as moderately resistant ('Chief' and 'Kingstar') survived (P = 0.05) inoculation with M. Hapla populations better than did 'Lobo' cultivar, which is classified as resistant. Plant growth of Nev Syn XX was suppressed by only the CA population, whereas growth of the other alfalfa cultivars classified as M. Hapla resistant or moderately resistant was suppressed by all nematode populations. Excluding Nev Syn XX, all alfalfa cultivars were severely galled and susceptible to all nematode populations. Except for Nev Syn XX, reproduction did not differ among the nematode populations on alfalfa cultivars. Nev Syn XX was not as favorable a host to CA as were the other cultivars; but, it was a good host (reproductive factor [Rf] = 37). Temperature affected plant resistance; the UT and WY populations were more pathogenic at 15-25 C, and CA was more pathogenic at 30 C. Nev Syn XX was susceptible to all nematode populations, except for CA, at only 30 C, and all other alfalfa cultivars were susceptible to all nematode populations at all temperatures. Key words: Alfalfa, Medicago sativa, Meloidogyne Hapla, Nematode, northern root-knot, population, race, reproduction, resistance, root growth, shoot growth, susceptibility, temperature.
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Pathological Relationship of Meloidogyne Hapla and Phytophthora megasperma F. Sp. Medicaginis in Twelve Medicago sativa L. Cultivars
Nematropica, 1994Co-Authors: G. D. Griffin, F. A. GrayAbstract:Effect of prior inoculation with Meloidogyne Hapla on the performance of 12 cultivars of alfalfa (Medicago sativa) with varying resistance to M. Hapla was studied under greenhouse conditions. Inoculation with the fungus alone caused plant mortality in the fungus-susceptible cultivar Deseret but not in susceptible Vernal. None of the P. megasperma f. sp. medicaginis-resistant cultivars died from Phytophthora root rot (PRR). Inoculation with M. Hapla alone resulted in mortality in nine of 12 cultivars. Combined inoculation of the two pathogens increased mortality in 10 of the 12 cultivars; only Nevada Synthetic XX (Nev Syn XX) germplasm and Chief with dual resistance were unaffected by the addition of the nematode. Inoculation with the fungus alone suppressed the dry shoot weight in four cultivars, including Vernal and Deseret, both susceptible to P. megasperma f. sp. medicaginis. Meloidogyne Hapla reduced dry shoot weights and reproduced on roots of all entries except Nev Syn XX. Melo
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Resistance of Lathyrus Species and Accessions to the Northern Root-knot Nematode, Meloidogyne Hapla
Journal of nematology, 1992Co-Authors: M. D. Rumbaugh, G. D. GriffinAbstract:The leguminous plant genus Lathyrus contains many species useful for soil conservation and reclamation. Some of these species may also have vaIue in the United States for forage production. The extent of genetic variation among Lathyrus populations in reaction to most disease pathogens is not known. We examined 28 USDA Agricultural Research Service Plant Introduction accessions representing 16 Lathyrus species for their ability to tolerate attack by the northern root-knot nematode, Meloidogyne Hapla. There were differences in the percentage of root tissue galled and in the nematode reproductive index among species and among accessions within species. Root biomass of infected plants was significantly less than that of uninfected plants of the same accession. Accessions of L. ochrus and L. tingitanus were susceptible to M. Hapla, whereas L. latifolius, L. sylvestris, and L. hirsutus were resistant. The variation among Lathyrus spp. in root galling and reproductive indices ofM. Hapla warrant the inclusion of these traits in Lathyrus breeding programs.