The hypothesis that inoculation of transplants with vesicular-arbuscular mycorrhizal (VAM) fungi before planting into saline soils would alleviate salt effects on growth and productivity was tested on lettuce (Lactuca sativa L.) and onion (Allium cepa L.). A secondary hypothesis was that the fungi isolated from a saline soil would be...
Large areas of non-coniferous communities in southwestern Oregon are thinned to reduce fire hazard and accomplish ecosystem restoration, under the assumption that current fuel loads are unnaturally high. Although Oregon white oak (Quercus garryana) woodlands are a characteristic landscape component in this region, little is known about their current or...
The heritability of resistance to eastern filbert blight, caused by Anisogramma anomala, in European hazelnut (Corylus avellana) was evaluated in the progeny of seven cultivars crossed in 12 combinations. Progeny produced by crossing 'VR6-28' with three susceptible cultivars segregated 1:1 for complete resistance to eastern filbert blight. Histograms of disease...
Biodiversity loss is of global concern, and is due in part to deforestation and high consumer demand for wood and wood products. The neotropical tree species Cedrela odorata (“Spanish cedar” or “cedro”) is economically valuable for its wood and faces threats of overexploitation. Due to strong similarities in wood features...
Classic biological control can be a powerful option for those tasked with managing biological invasions; however, some biocontrol releases lead to non-target attack – feeding, damage or development on species other than the target species. The cinnabar moth, Tyria jacobaeae L. (Lepidoptera: Erebidae) was introduced to Western Oregon as a...
A multi-year field study was conducted in Oregon and Washington to evaluate the influence of nitrogen fertilization rate and timing on cone quality, nitrate accumulation in cones, severity of powdery mildew (caused by Podosphaera macularis), arthropod pests, and the stability of conservation biological control of the twospotted spider mite (Tetranychus...
I studied the water relations traits, twig conductivity, C'3 isotopic composition,
and wood density of three conifer and five angiosperm species in western Oregon. This
study took place from spring 2002 to fall 2003 on four sites. Species were selected to
represent the diversity of drought tolerance of woody plants...
Whitebark pine (Pinus albicaulis) is an iconic North American high-elevation tree species currently threatened by climate change, mountain pine beetle, and white pine blister rust (WPBR), a lethal disease caused by the non-native fungal pathogen Cronartium ribicola. In collaboration with the USDA Forest Service Dorena Genetic Resource Center, germplasm was...
The abundance of algal species and their parasites
was monitored weekly for two years in a sewage lagoon
at the Corvallis Airport, Oregon. During the cooler
months, Euglena species were dominant followed by a
Chlamydomonas assemblage in the spring and a
predominantly Scenedesmus assemblage in the summer and
fall. Parasites...