Nurseries are an important part of the agriculture industry of the United States. The nursery industry provides ornamental, forest, restoration and specialty products to many markets in N. America. The disease sudden oak death, caused by Phytophthora ramorum, has devastating environmental and economic impacts on forested land, the urban-forest interface,...
Nursery and greenhouse products are economically important agricultural commodities for Oregon and Washington. Nursery crops including tree seedlings can be damaged or killed by soilborne plant pathogens, which can be challenging to manage because of their persistence in soil and limited options for control. Soil solarization is a pre-planting soil...
Phytophthora ramorum continues to cause extensive mortality of tanoaks in southwestern Oregon. Rain readily washes inoculum down through the canopy, causing new infections on the lower parts of the tree and neighboring host plants. Although this aspect of dispersal is well understood, the relative importance of infested soil and leaf...
Phytophthora pini Leonian, recently re-established from P. citricola
I, is a pathogen with a wide range of forest and nursery hosts. It causes foliar
infections in horticultural nurseries in Oregon, where recirculating irrigation
systems are common. Increased use of recirculating irrigation systems may
contribute to disease caused by waterborne plant...
The sudden oak death pathogen, Phytophthora ramorum, is present in southwestern Oregon, and while an eradication effort is underway, the potential impact of the polyphagous pathogen on surrounding vegetation is unknown. Plant communities in the area are substantially different from those affected in California, although tanoak (Lithocarpus densiflorus), evergreen huckleberry...
Striga, a genus of obligate parasitic weeds in the family Orobanchaceae, has been
identified as the most important biological factor limiting agricultural productivity in sub-Saharan Africa. Germination of Striga seeds is triggered by strigolactone root exudates
from host plants. Strigolactones also induce hyphal branching in arbuscular mycorrhizal
(AM) fungi, which...
Phytophthora ramorum, a plant pathogen, is the cause of sudden oak death and ramorum blight and shoot die-back. It has a wide host range including many native forest species and common nursery plants. The lack of knowledge regarding infection biology of P. ramorum limits our understanding of its ecology and...
Coast redwood (Sequoia sempervirens) (D. Don) Endl. is a host for Phytophthora ramorum but it was unclear if the pathogen represents a significant disease risk to this tree species. In this study the susceptibility of coast redwood seedlings and the likelihood of sporulation on redwood were examined. Two methods were...
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JenniferL. Parke
Coast redwood (Sequoia sempervirens) (D. Don) Endl. is a host for
In horticultural nurseries for container-grown plants, production and sales have been threatened by the presence of a quarantined plant pathogen, Phytophthora ramorum (causal agent of sudden oak death). Infested nursery beds are an important source of P. ramorum, which can initiate disease through movement with surface water to infect roots...
Burkholderia cepacia complex (Bcc) bacteria reside in soil, plant rhizospheres, and water, but the prevalence of Bcc in outdoor environments is not clear. In this study, we sampled a variety of soil and rhizosphere environments with which people may have contact: playgrounds, athletic fields, parks, hiking trails, residential yards and...
The genus Phytophthora comprises numerous plant pathogens in both natural and managed ecosystems. For Phytophthora spp. that infect roots, dispersal occurs in soil water through a combination of advection and swimming of specialized motile propagules (zoospores). Specific biological and physico-chemical processes, however, remain poorly understood, due to difficulties in studying...
Weed management is one of the main challenges for organic agriculture. Soil solarization has been shown to be an effective mitigation strategy for weeds and soil borne plant pathogens but few studies have been conducted in cooler climates such as the Pacific Northwest.
Solarization could be an alternative to chemical controls for soil pathogens and weeds, and it may also influence plant growth factors. Biomass, shoot length, and AMF colonization were examined in red oak (Quercus rubra), Mazzard cherry (Prunus avium), and hawthorn (Crataegus monogyna) at J. Frank Schmidt & Son Co. nursery...
Infestations of container nursery beds by Phytophthora spp. can be persistent and costly. One method of disinfestation that does not require the use of chemicals is soil solarization, which captures energy from the sun to heat soil and thermally inactivate target pathogens. In laboratory temperature gradient experiments, I investigated the...
Interest in measuring soil quality continues to increase worldwide in view of demands on land productivity and the necessity to preserve soil resources, yet identification of suitable indicators for soil quality assessment is still evolving. This study adapted 10 biological, physical, and chemical indicators of soil quality identified by the...
Phytophthora ramorum, an oomycete plant pathogen, is the causal agent of sudden oak death, a serious disease of Fagaceous trees in California and Oregon over the last decade. Tanoak (Notholithocarpus densiflorus) is one of the most susceptible host species, but the cause of host mortality is poorly understood. Previous research...
Tanoak (Lithocarpus densiflorus), along with some other members of Fagaceae, are susceptible to sudden oak death caused by the oomycete Phytophthora ramorum. Symptoms of the disease include dying crowns, bleeding cankers, and eventually death of infected trees. The cause of mortality is not well understood, but recent research indicates that...
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JenniferL. Parke
Tanoak (Lithocarpus densiflorus), along with some other members of
Soil solarization has been used throughout the world, but its effect on plant growth variables in ornamental tree saplings in the Willamette Valley are not well documented. Solarization could be an alternative to chemical controls for soil pathogens and weeds, and it may also influence plant growth factors. This study...
Osteosarcoma (OS) is the most common primary bone tumor in both humans and dogs, occurring approximately 10 times more frequently in dogs. OS is a highly aggressive neoplasm with evidence of metastasis often found at the time of diagnosis. Long-term survival in afflicted dogs continues to remain low despite aggressive...
Many trace elements (e.g., Zn, Cd, Mo) are essential phytoplankton micronutrients, making them crucial to the marine ecosystem and ultimately the carbon cycle. Because of this association trace metals are also utilized in paleoceanographic studies (e.g., Mo, Cd). However, not much is known about what controls the cycling of these...
