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Gary A. Chastagner - One of the best experts on this subject based on the ideXlab platform.

  • interactions between root rotting phytophthora abies Christmas Trees and environment
    Plant Disease, 2019
    Co-Authors: Kathleen Mckeever, Gary A. Chastagner
    Abstract:

    Defining host-pathogen interactions between species of root-rotting Phytophthora and Abies in Christmas tree production areas is important for tailoring management activities on a regional scale and for developing molecular tools for identifying resistant host species. Classifying Abies species as resistant or susceptible is complicated by regional variation in abundance and aggressiveness of Phytophthora species and the influence of environment on symptom expression and host vigor. Because previous studies performed to assess host response to Phytophthora root rot (PRR) have focused on one or a few species of either the host or pathogen, a multifactorial experiment was conducted to assess the responses of seven species of Abies challenged with three isolates each of four Phytophthora species under contrasting temperature conditions. Evaluation of mortality, root rot severity, and remaining root biomass after 16 weeks of exposure to the pathogen confirmed prior inferences regarding inherent variation in the resistance responses of various species of Abies and demonstrated evidence of variation in aggressiveness among species of Phytophthora as well as different isolates of the same Phytophthora species. The ambient temperatures at which studies were conducted had a conspicuous effect on host mortality, root rot severity, and radial growth of Phytophthora. Understanding how host responses differ under variable pathogen attack and ambient environment will improve efforts to control PRR using host species substitutions on infested ground.

  • use of shaking treatments and preharvest sprays of pyrethroid insecticides to reduce risk of yellowjackets and other insects on Christmas Trees imported into hawaii
    Journal of Economic Entomology, 2009
    Co-Authors: Robert G Hollingsworth, Gary A. Chastagner, Neil J Reimer, Darcy E Oishi, Peter J Landolt, Robert E Paull
    Abstract:

    Insects are commonly found by Hawaii's quarantine inspectors on Christmas Trees imported from the Pacific Northwest. To reduce the risk of importing yellowjacket (Vespula spp.) queens and other insects, an inspection and tree shaking certification program was begun in 1990. From 1993 to 2006, the annual percentage of shipped containers rated by Hawaii quarantine inspectors as moderately or highly infested with insects was significantly higher for manually shaken Trees than for mechanically shaken Trees. Between 1993 and 2001, 343 insect species in total were recovered from Christmas Trees. Live western yellowjacket [Vespula pensylanica (Saussure) ] queens were intercepted both from containers certified as manually shaken and from containers certified as mechanically shaken. The standard manual shaking protocol removed about one-half of the queens from Douglas fir [Pseudotsuga menziesii (Mirb.) Franco] Trees that were naturally infested with western yellowjacket queens. We investigated the use of preharvest sprays of permethrin as a complement to shaking procedures used to control yellowjackets and other insects. Western yellowjacket queens and honey bees (surrogates for wasp pests) were exposed to Noble fir foliage that had been sprayed in the field with permethrin >6 wk before harvest. Pesticide residues provided complete control (moribundity or mortality) in both species. The sprays did not affect needle retention or quality of Noble fir foliage. We conclude that preharvest sprays of pyrethroid insecticides could be used in combination with mechanical shaking to greatly reduce the quarantine risk of yellowjacket queens and other insects in exported Christmas Trees.

  • Phytophthora ramorum isolated from California bay laurel inflorescences and mistletoe: possible implications relating to disease spread
    2008
    Co-Authors: Gary A. Chastagner, Kathy Riley, Norm Dart
    Abstract:

    Since 2005, we have been studying the spread and development of Phytophthora ramorum at a Christmas tree farm near Los Gatos, California. This research has shown that distance from infected plants, predominantly California bay laurel (Umbellularia californica) (referred to as ?bay? throughout), is an important factor relating to the infection of Douglas-fir (Pseudotsuga menziesii) and grand fir (Abies grandis) Christmas Trees at our research site. This abstract reports two case studies involving the possible role that bay inflorescences and mistletoe may play in the spread of P. ramorum.

  • effectiveness of i v watering devices in maintaining postharvest freshness and quality of cut Christmas Trees
    Postharvest Biology and Technology, 2007
    Co-Authors: Gary A. Chastagner, Eric Hinesley, Kathy Riley
    Abstract:

    Abstract Experiments were carried out with cut Douglas-fir ( Pseudotsuga menziezii (Mirb.) Franco) and Leyland cypress [x Cupressocyparis leylandii (A.B. Jacks. & Dallim.)] Christmas Trees to evaluate postharvest water uptake, moisture status, needle loss, and tree quality when water was supplied to displayed Trees either by an I–V device or a traditional method of placing the base in water. In both experiments, Trees consumed about 4× as much water with the traditional method. Based on measurements of twig moisture content, xylem pressure potential ( Ψ ), needle loss, and total water consumption, tree freshness and quality was adequately maintained by the traditional method, but not the I–V device.

  • postharvest quality of noble and nordmann fir Christmas Trees
    Hortscience, 2003
    Co-Authors: Gary A. Chastagner, Kathleen L Riley
    Abstract:

    Moisture and needle loss characteristics were similar for noble (Abies procera Red.) and Nordmann fir [Abies nordmanniana (Stev.) Spach.] Christmas Trees that were displayed in water. After 42 days, Trees still had xylem pressure potentials above -2 MPa. In addition, Trees that were displayed in water had very little needle loss. When Trees were displayed dry, noble and Nordmann fir had similar rates of moisture loss, drying to about -6 MPa in about 3 weeks. Although there was very little needle loss from any of the noble fir Trees that were displayed dry, some Nordmann fir Trees began to shed large numbers of green needles within 3 to 5 days, which significantly reduced postharvest quality. Unless sources of Nordmann fir are identified that have good needle retention characteristics, the needle loss problem observed when Trees dry to about -3 MPa has the potential to limit the use of this species as a Christmas tree in the United States.

Communications Team - One of the best experts on this subject based on the ideXlab platform.

Robert K Lawrence - One of the best experts on this subject based on the ideXlab platform.

  • tomicus piniperda coleoptera scolytidae shoot feeding characteristics and overwintering behavior in scotch pine Christmas Trees
    Journal of Economic Entomology, 2001
    Co-Authors: Robert A Haack, Robert K Lawrence, George C Heaton
    Abstract:

    Overwintering behavior of Tomicus piniperda (L.) was studied in a Scotch pine (Pinus sylvestris L.) Christmas tree plantation in Indiana (1992-1994) and a plantation in Michigan (1994). In general, adults feed inside shoots during summer, then move to overwintering sites at the base of Trees in autumn. In early autumn, adults were most often found in shoot-feeding tunnels that were still surrounded by green needles, whereas few were in tunnels surrounded by yellow or brown needles. For all years and sites combined, the range in the percentage of recently tunneled shoots that contained live T. piniperda adults decreased from 89 to 96% in mid-October, to 15-66% in early November, to 2-10% in mid-November, and to 0-2% by late November to early December. In each year, the first subfreezing temperatures in autumn occurred in October, before most adults left the shoots. Of 1,285 T. piniperda-tunneled shoots, one to seven tunnels (mean = 1.6) and zero to three adults were found per infested shoot. Of these 1,285 attacked shoots, 55% of the shoots had one tunnel, 33%had two, 9%had three, 3%had four, and < 1%had five to seven tunnels each. When two or more tunnels occurred in a single shoot, adults were most commonly found in the innermost (most basal) tunnel. For the 2,070 tunnels found in the 1,285 shoots, average shoot thickness at the tunnel entrance was 6.0 mm, average distance from the tunnel entrance to the shoot tip was 6.3 cm, and average tunnel length was 2.3 cm. Four Scotch pine Christmas Trees were dissected in January 1993. Eighty percent of the tunneled shoots were in the upper quarter of the tree crown and 98% were in the upper half. For the four Trees inspected in January, one live adult was found in a shoot and 85 adults were found in the outer bark along the lower trunk from 1cm below the soil line to 19 cm above the soft line. No overwintering adults were found outside the trunk in the duff or soil near the base of each test tree. Implications of these results are discussed in terms of surveying, timing the cutting of Christmas Trees, and cutting height for Christmas Trees.

  • tomicus piniperda coleoptera scolytidae reproduction and behavior on scotch pine Christmas Trees taken indoors
    Great Lakes Entomologist, 1997
    Co-Authors: Robert A Haack, Robert K Lawrence
    Abstract:

    Tomicus piniperda, the pine shoot beetle, is an exotic insect that was first found in North America in 1992. A federal quarantine currently restricts movement of pine products, including Christmas Trees, from infested to uninfested counties. We conducted a study to determine if T. piniperda would reproduce in Christmas Trees that were cut and taken indoors during the Christmas season. Twelve Scotch pine, Pinus sylvestris, Christmas Trees in- fesed with overwintering T. piniperda beetles were cut in Indiana in early December 1993 and taken to Michigan. Four Trees were dissected immediately, while the other 8 Trees were taken indoors, placed in tree stands, and watered regularly. After 4 weeks indoors, 4 Trees were dissected, and the other 4 were placed outdoors in Michigan for 7 weeks. Upon dissection, all overwintering sites occurred along the lower trunk within the first 40 cm of the soil line; 81% were found within 10 cm of the soil line. Adults collected from the 4 Trees dissected in December produced viable progeny adults when placed on Scotch pine logs in the laboratory. Overwintering beetles became active and laid eggs in 4 of the 8 Trees that had been taken indoors. All adults and progeny found in the 4 Trees that had been placed outdoors for 7 weeks during cold January and February temperatures were dead. Overall, T. piniperda can become active and breed in Christmas Trees that are cut and taken, indoors in December. Tomicus piniperda survival in Trees that are discarded outdoors at the end of the Christmas season will depend largely on the prevailing temperatures.

Robert A Haack - One of the best experts on this subject based on the ideXlab platform.

  • tomicus piniperda coleoptera scolytidae shoot feeding characteristics and overwintering behavior in scotch pine Christmas Trees
    Journal of Economic Entomology, 2001
    Co-Authors: Robert A Haack, Robert K Lawrence, George C Heaton
    Abstract:

    Overwintering behavior of Tomicus piniperda (L.) was studied in a Scotch pine (Pinus sylvestris L.) Christmas tree plantation in Indiana (1992-1994) and a plantation in Michigan (1994). In general, adults feed inside shoots during summer, then move to overwintering sites at the base of Trees in autumn. In early autumn, adults were most often found in shoot-feeding tunnels that were still surrounded by green needles, whereas few were in tunnels surrounded by yellow or brown needles. For all years and sites combined, the range in the percentage of recently tunneled shoots that contained live T. piniperda adults decreased from 89 to 96% in mid-October, to 15-66% in early November, to 2-10% in mid-November, and to 0-2% by late November to early December. In each year, the first subfreezing temperatures in autumn occurred in October, before most adults left the shoots. Of 1,285 T. piniperda-tunneled shoots, one to seven tunnels (mean = 1.6) and zero to three adults were found per infested shoot. Of these 1,285 attacked shoots, 55% of the shoots had one tunnel, 33%had two, 9%had three, 3%had four, and < 1%had five to seven tunnels each. When two or more tunnels occurred in a single shoot, adults were most commonly found in the innermost (most basal) tunnel. For the 2,070 tunnels found in the 1,285 shoots, average shoot thickness at the tunnel entrance was 6.0 mm, average distance from the tunnel entrance to the shoot tip was 6.3 cm, and average tunnel length was 2.3 cm. Four Scotch pine Christmas Trees were dissected in January 1993. Eighty percent of the tunneled shoots were in the upper quarter of the tree crown and 98% were in the upper half. For the four Trees inspected in January, one live adult was found in a shoot and 85 adults were found in the outer bark along the lower trunk from 1cm below the soil line to 19 cm above the soft line. No overwintering adults were found outside the trunk in the duff or soil near the base of each test tree. Implications of these results are discussed in terms of surveying, timing the cutting of Christmas Trees, and cutting height for Christmas Trees.

  • tomicus piniperda coleoptera scolytidae reproduction and behavior on scotch pine Christmas Trees taken indoors
    Great Lakes Entomologist, 1997
    Co-Authors: Robert A Haack, Robert K Lawrence
    Abstract:

    Tomicus piniperda, the pine shoot beetle, is an exotic insect that was first found in North America in 1992. A federal quarantine currently restricts movement of pine products, including Christmas Trees, from infested to uninfested counties. We conducted a study to determine if T. piniperda would reproduce in Christmas Trees that were cut and taken indoors during the Christmas season. Twelve Scotch pine, Pinus sylvestris, Christmas Trees in- fesed with overwintering T. piniperda beetles were cut in Indiana in early December 1993 and taken to Michigan. Four Trees were dissected immediately, while the other 8 Trees were taken indoors, placed in tree stands, and watered regularly. After 4 weeks indoors, 4 Trees were dissected, and the other 4 were placed outdoors in Michigan for 7 weeks. Upon dissection, all overwintering sites occurred along the lower trunk within the first 40 cm of the soil line; 81% were found within 10 cm of the soil line. Adults collected from the 4 Trees dissected in December produced viable progeny adults when placed on Scotch pine logs in the laboratory. Overwintering beetles became active and laid eggs in 4 of the 8 Trees that had been taken indoors. All adults and progeny found in the 4 Trees that had been placed outdoors for 7 weeks during cold January and February temperatures were dead. Overall, T. piniperda can become active and breed in Christmas Trees that are cut and taken, indoors in December. Tomicus piniperda survival in Trees that are discarded outdoors at the end of the Christmas season will depend largely on the prevailing temperatures.

Michael Haarhaus - One of the best experts on this subject based on the ideXlab platform.

  • Pythium undulatum, cause of root rot of Abies procera Christmas Trees and Pseudotsuga menziesii in Northern Germany
    Mycological Progress, 2004
    Co-Authors: Roland W. S. Weber, Frank-ludger Sulzer, Michael Haarhaus
    Abstract:

    A devastating disease of Abies procera grown as Christmas Trees in a forest situation in Northern Germany is reported. Disease symptoms began as a root rot with disintegration of the cortex of lateral and main roots, followed by rapid chlorosis and necrosis of the foliage which had a striking copper colour on dead and dying Trees. All disease symptoms were reproducible in pathogenicity tests with potted A. procera and Pseudotsuga menziesii plants infected with the isolated pathogen. The symptoms were indistinguishable from those reported for Phytophthora spp., but the pathogen was identified by microscopy and ITS sequence analysis as Pythium undulatum , which has not previously been described as a cause of root rot of coniferous Trees in outdoor situations. This fungus was isolated also from roots of A. amabilis, A. grandis and P. menziesii showing similar below-and above-ground symptoms. Trees of varying ages (6–22 years) were affected. Abies nordmanniana appeared not to be susceptible to P. undulatum even when in direct root contact with diseased A. procera or A. amabilis . The establishment and spread of the disease between 1999 and 2002 appeared to be correlated with poor soil drainage following a series of unusually wet summers.