Peppermint, Mentha piperita 'Black Mitcham' was established as a host for tomato
spotted wilt virus-impatiens serotype (TSWV-I). TSWV-I infection of peppermint,
initially observed in a research greenhouse (Corvallis, OR), included stunting and
downward curling of leaves accompanied by bronzing, and occasionally tip necrosis.
Young leaves appeared either symptomless, deformed, or...
Tile drainage increases aeration in the root zone of poorly drained soils by
accelerating water movement from the subsurface. Water movement is the main agent
of chemical transport, either transporting soluble materials directly (e.g., nitrate) or by
transporting the soil particles that bind adsorptive compounds (e.g., pesticides). The
detection frequency...
We use qualitative and quantitative methods to explore social and spatial relationships between land ownership and forest cover in the Oregon Coast Range. Using a Geographic Information System (GIS) and regression analysis, we tested for spatial relationships between the structure of land ownership and forest cover across 66 watersheds in...
Prescribed burning is increasingly being used as a management tool to reduce potential fuels on the forest floor and promote stand vigor through removal of dense, crowded vegetation. Because fire affects both the standing vegetation and the amount of downed wood in the ecosystem, it is imperative to examine how...
European hazelnut, an important nut crop in Oregon agriculture, is threatened by the fungal disease eastern filbert blight (EFB) caused by Anisogramma anomala (Peck) E. Müller. The hazelnut breeding program at OSU has been working on development of EFB-resistant cultivars. DNA markers allow mapping of traits using segregating progenies and...
Hypersensitive response-like (HR-like) needle reactions to infection by the white pine blister rust pathogen, Cronartium ribicola, have been reported for several species of five needle pines native to western North America. The best-studied examples are in Pinus monticola and P. lambertiana. In these species a "needle spot" phenotype has been...
Root rot diseases of bean (Phaseolus vulgaris L.) are a problem wherever they are grown, and are a major constraint to dry edible and snap bean production. Root rot is a primary yield limitation of snap bean production in the US, especially within the top three snap bean producing states...
This study quantified the frequency of simple versus
complex races of Puccinia striiformis Westend. in mixtures
of wheat cultivars possessing different race-specific
resistance genes. A simple race of a pathogen can infect
only one component, and a complex race of the pathogen can
infect two or more components of an...
Intra- and interplant movement and dispersal of the predator mites Neoseiulus californicus (McGregor) and Neoseiulus fallacis (Garman) were studied on both lima bean (Phaseolus lunatus L.) and apple (Malus pumila Miller) branch plant systems that were seeded with excess numbers of the spider mite Tetranychus urticae Koch. Individuals of either...
Yeast biocontrol agents that were applied to 'Bose' and 'Anjou' pears in the field up to three weeks prior to harvest were found to survive on the fruit at high population levels on both pear varieties. Cryptococcus infirmo-miniatus, Cryptococcus laurentii, and Rhodotorula glutinis maintained populations averaging 5 x 10⁶ cfu/fruit...
The effects of forest cutting on forested systems and the biotic components of those systems has been at the forefront of scientific research. The inventory and monitoring of biodiversity is one technique used for measuring the effects of forest management. Because bioinventory studies are expensive, indicator species are often sought...
The objective of this dissertation is to introduce low-cost processing methods for the fabrication of ZnO transparent thin-film transistors (TTFTs). A novel method for depositing ZnO body layers via spin-coating of a zinc nitrate-based spin solution is presented. The processing conditions of spin-coated ZnO are optimized to produce continuous and...
Small broomrape (Orobanche minor) is a parasitic weed that attaches to the roots of red clover (Trifolium pratense). Small broomrape invasion presents a significant threat to the future of red clover seed production in Oregon. This study was conducted to investigate and develop small broomrape management options for red clover...
Experiments were performed to determine the nature of
maize influence on bean disease in additive-type
intercrops. Overall effects of intercrops on angular leaf
spot (caused by Phaeoisariopsis griseola) in Kenya
indicated >23% reductions (P<0.05) in area under the
disease progress curve (AUDPC) in two of three season-site
combinations. Fertilization tended...
Most studies of plant disease epidemiology have focused on epidemics in host
populations composed of a single genotype. But crop plant diversity can be a useful
means of improving the deployment of resistance genes. In a series of experiments with wheat stripe rust and potato late blight, we studied factors...
Specialist and generalist phytoseiid mites are widely used for biological
control of spider mites. Understanding dispersal attributes of these mites is
important to implementing more stable, cost-efficient integrated pest management.
In this regard, we studied dispersal of phytoseiid mites from a local ambulatory
phase of movement within a prey patch...
Characterization of the determinants of economically important phenotypes
showing complex inheritance should lead to more effective use of genetic
resources. This study was conducted to determine the number, genome location and
effects of QTLs determining malting quality and agronomic traits in the two North
American barley quality standards. Using a...
The purpose of this research was to develop tools and germplasm for the production of tomatoes (Solanum lycopersicum L.) with high fruit phenolics without the use of genetic engineering. A candidate gene analysis was undertaken to identify genes regulating anthocyanin biosynthesis in tomato fruit (Aft, Abg, atv, and Purple Smudge)....
Landscape plants are highly diverse and nursery producers often grow thousands of taxa to satisfy the varied needs and aesthetic tastes of consumers. Related to this diversity, ornamental plant breeders must be nimble and diverse in their approach. Two seemingly disparate studies were conducted to investigate improving ornamental shrubs –...