The Experts below are selected from a list of 807 Experts worldwide ranked by ideXlab platform

Cornell University - One of the best experts on this subject based on the ideXlab platform.

Bruce C Kirkpatrick - One of the best experts on this subject based on the ideXlab platform.

  • identification of phytoplasma taxa and insect vectors of peach yellow leaf roll disease in california
    Plant Disease, 2002
    Co-Authors: C L Blomquist, Bruce C Kirkpatrick
    Abstract:

    ABSTRACT Two peach diseases in California, western X-disease (WX) and peach yellow leaf roll (PYLR) are caused by two genetically distinct phytoplasmas. Based on symptoms alone, WX and PYLR cannot be reliably distinguished. The objectives of this study were to determine which phytoplasma was causing PYLR disease in peach orchards planted near pear orchards and which phytoplasmas were present in potential insect vectors captured in both peach and pear orchards. Leafhoppers and pear Psylla were collected from yellow sticky traps placed in three pear orchards and four peach orchards located in the Sacramento Valley from 1994 to 1996. DNA was extracted from potential vectors and suspect diseased trees, and analyzed for the presence of the WX and PYLR phytoplasmas using strain-specific DNA hybridization or polymerase chain reaction (PCR) assays. The most abundant phytoplasma detected in diseased peach trees was the PYLR phytoplasma. In 1994 and 1995, 10 to 25% of groups of pear Psylla tested positive for the P...

  • identification of phytoplasma taxa and insect vectors of peach yellow leaf roll disease in california
    Plant Disease, 2002
    Co-Authors: C L Blomquist, Bruce C Kirkpatrick
    Abstract:

    Two peach diseases in California, western X-disease (WX) and peach yellow leaf roll (PYLR) are caused by two genetically distinct phytoplasmas. Based on symptoms alone, WX and PYLR cannot be reliably distinguished. The objectives of this study were to determine which phytoplasma was causing PYLR disease in peach orchards planted near pear orchards and which phytoplasmas were present in potential insect vectors captured in both peach and pear orchards. Leafhoppers and pear Psylla were collected from yellow sticky traps placed in three pear orchards and four peach orchards located in the Sacramento Valley from 1994 to 1996. DNA was extracted from potential vectors and suspect diseased trees, and analyzed for the presence of the WX and PYLR phytoplasmas using strain-specific DNA hybridization or polymerase chain reaction (PCR) assays. The most abundant phytoplasma detected in diseased peach trees was the PYLR phytoplasma. In 1994 and 1995, 10 to 25% of groups of pear Psylla tested positive for the PYLR phytoplasma, while no Psylla groups tested positive for the WX phytoplasma. Only one captured leafhopper tested positive for the WX phytoplasma. These results indicate the pear Psylla is the primary vector of PYLR in northern California.

New York State Agricultural Experiment Station - One of the best experts on this subject based on the ideXlab platform.

C L Blomquist - One of the best experts on this subject based on the ideXlab platform.

  • identification of phytoplasma taxa and insect vectors of peach yellow leaf roll disease in california
    Plant Disease, 2002
    Co-Authors: C L Blomquist, Bruce C Kirkpatrick
    Abstract:

    ABSTRACT Two peach diseases in California, western X-disease (WX) and peach yellow leaf roll (PYLR) are caused by two genetically distinct phytoplasmas. Based on symptoms alone, WX and PYLR cannot be reliably distinguished. The objectives of this study were to determine which phytoplasma was causing PYLR disease in peach orchards planted near pear orchards and which phytoplasmas were present in potential insect vectors captured in both peach and pear orchards. Leafhoppers and pear Psylla were collected from yellow sticky traps placed in three pear orchards and four peach orchards located in the Sacramento Valley from 1994 to 1996. DNA was extracted from potential vectors and suspect diseased trees, and analyzed for the presence of the WX and PYLR phytoplasmas using strain-specific DNA hybridization or polymerase chain reaction (PCR) assays. The most abundant phytoplasma detected in diseased peach trees was the PYLR phytoplasma. In 1994 and 1995, 10 to 25% of groups of pear Psylla tested positive for the P...

  • identification of phytoplasma taxa and insect vectors of peach yellow leaf roll disease in california
    Plant Disease, 2002
    Co-Authors: C L Blomquist, Bruce C Kirkpatrick
    Abstract:

    Two peach diseases in California, western X-disease (WX) and peach yellow leaf roll (PYLR) are caused by two genetically distinct phytoplasmas. Based on symptoms alone, WX and PYLR cannot be reliably distinguished. The objectives of this study were to determine which phytoplasma was causing PYLR disease in peach orchards planted near pear orchards and which phytoplasmas were present in potential insect vectors captured in both peach and pear orchards. Leafhoppers and pear Psylla were collected from yellow sticky traps placed in three pear orchards and four peach orchards located in the Sacramento Valley from 1994 to 1996. DNA was extracted from potential vectors and suspect diseased trees, and analyzed for the presence of the WX and PYLR phytoplasmas using strain-specific DNA hybridization or polymerase chain reaction (PCR) assays. The most abundant phytoplasma detected in diseased peach trees was the PYLR phytoplasma. In 1994 and 1995, 10 to 25% of groups of pear Psylla tested positive for the PYLR phytoplasma, while no Psylla groups tested positive for the WX phytoplasma. Only one captured leafhopper tested positive for the WX phytoplasma. These results indicate the pear Psylla is the primary vector of PYLR in northern California.

Philippe Guérif - One of the best experts on this subject based on the ideXlab platform.

  • polygenic inheritance of resistance to cacoPsylla pyri in a pyrus communis p ussuriensis progeny is explained by three qtls involving an epistatic interaction
    Tree Genetics & Genomes, 2016
    Co-Authors: Laure Perchepied, Philippe Guérif, Caroline Denance, Yves Lespinasse, Elisa Ravon, Francois Laurens, Philippe Robert, L Bouvier, Charles Eric Durel
    Abstract:

    Pear Psylla (CacoPsylla pyri) causes severe damage on European pear cultivars, resulting in high yield losses. Its control has become difficult since it developed resistance to a wide range of pesticides, while the number of authorized molecules for pest control has decreased. Identifying pear Psylla resistance factors should help breeding new resistant pear cultivars. We analyzed the quantitative resistance to Psylla inherited from the genotype NY 10355 derived from Pyrus ussuriensis. Quantitative trait locus (QTL) analysis was carried out after counting the number of nymphs and estimating the nymphal development rate using a free-choice test performed on a large segregating progeny. We mapped two new loci for pear Psylla resistance on linkage groups LG01 and LG04 of NY 10355 and confirmed the QTL previously detected on LG17. A strong epistatic interaction between the two QTLs detected on LG01 and LG17 appeared to be a major factor controlling the Psylla infestation in the genotype NY 10355.

  • Polygenic inheritance of resistance to CacoPsylla pyri in a Pyrus communis × P. ussuriensis progeny is explained by three QTLs involving an epistatic interaction
    'Springer Science and Business Media LLC', 2016
    Co-Authors: Laure Perchepied, Philippe Guérif, Caroline Denance, Yves Lespinasse, Elisa Ravon, Francois Laurens, Philippe Robert, L Bouvier, Charles Eric Durel
    Abstract:

    Pear Psylla (CacoPsylla pyri) causes severe damage on European pear cultivars, resulting in high yield losses. Its control has become difficult since it developed resistance to a wide range of pesticides, while the number of authorized molecules for pest control has decreased. Identifying pear Psylla resistance factors should help breeding new resistant pear cultivars. We analyzed the quantitative resistance to Psylla inherited from the genotype NY 10355 derived from Pyrus ussuriensis. Quantitative trait locus (QTL) analysis was carried out after counting the number of nymphs and estimating the nymphal development rate using a free-choice test performed on a large segregating progeny. We mapped two new loci for pear Psylla resistance on linkage groups LG01 and LG04 of NY 10355 and confirmed the QTL previously detected on LG17. A strong epistatic interaction between the two QTLs detected on LG01 and LG17 appeared to be a major factor controlling the Psylla infestation in the genotype NY 10355

  • Genetic mapping of CacoPsylla pyri resistance in an interspecific pear (Pyrus spp.) population
    Tree Genetics and Genomes, 2015
    Co-Authors: Sara Montanari, Philippe Guérif, Caroline Denance, Elisa Ravon, Philippe Robert, Helene Muranty, Ricardo Velasco, David Chagné, Vincent G. M. Bus, Laure Perchepied
    Abstract:

    CacoPsylla pyri (pear Psylla) is one of the most serious pests of pear (Pyrus spp.) in Europe. It can cause high yield losses, and its control has become difficult since it has developed resistance to a wide range of pesticides. Pear breeders are developing new cultivars resistant to pear psyllids, and Asian species, such as Pyrus ussuriensis and Pyrus × bretschneideri, are good sources of resistance. Antixenosis and antibiosis resistance to Psylla were both identified in pear; they may differ in the biological mechanism and probably have different genetic backgrounds. We crossed interspecific P. × bretschneideri × Pyrus communis hybrid PEAR3, resistant to pear Psylla, with the susceptible European pear cultivar ‘Moonglow’ to obtain an F1 population for the genetic mapping of the resistance. Quantitative trait locus (QTL) analysis was carried out for antibiosis by measuring the number of surviving nymphs and the nymphal development, using a novel phenotyping protocol and a saturated genetic map made of single-nucleotide polymorphism (SNP) and microsatellite (simple sequence repeats (SSR)) markers. A stable QTL was detected on linkage group (LG) 8 of PEAR3 (R 2 = 17.2–39.1 %). In addition, QTLs were detected on LG5 (R 2 = 10.8 %) of PEAR3 and on LG15 of ‘Moonglow’ (R 2 = 13.7 %).

  • European pear cultivar resistance to bio-pests: scab (Venturia pirina) and Psylla (CacoPsylla pyri).
    2010
    Co-Authors: Lydie Bouvier, Marie Bourcy, Mathieu Boulay, Marie Tellier, Philippe Guérif, Caroline Denance, Charles Eric Durel, Yves Lespinasse
    Abstract:

    Scab (Venturia pirina), and pear Psylla (CacoPsylla pyri) lead to severe damage on European pear cultivars resulting in a loss of commercial value and requiring frequent use of chemical sprays. Most European pear cultivars are currently reported to be sensitive. Identifying scab resistance genes, developing molecular markers linked to these genes and establishing a marker-assisted-selection (MAS) would be an effective way to improve European pear breeding for pest resistance and then reduce the chemical impact on the environment. The pear cultivar 'Navara' was shown to carry a major scab resistance gene with phenotypic expression in seedling progenies as a typical stellate necrosis symptom. The resistance gene was called Rvp1, for resistance to Venturia pirina, and was mapped on linkage group 2 of the pear genome close to the marker CH02b10. This genomic region is known to carry a cluster of scab resistance genes in apple indicating a first functional synteny for scab resistance between apple and pear. The progeny of the European pear 'Angelys' crossed with a resistant genotype 'NY10355' allow us to analyze the quantitative resistance to pear Psylla. Following screening of the parents and seedlings with microsatellite markers, a QTL (Quantitative Trait Loci) analysis has been conducted. A QTL which explains 15% of the phenotypic variability has been mapped on the linkage group 17.

  • Pear breeding for Scab and Psylla resistance
    2007
    Co-Authors: Yves Lespinasse, Marie Tellier, Philippe Guérif, Caroline Denance, Charles Eric Durel, M. Chevalier, Andre Belouin, Philippe Robert
    Abstract:

    Pear breeding for Scab and Psylla resistance. Xth International Symposium on Pear Growing