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...
A survey of major bean (Phaseolus vulgaris) breeding programs and
seed producing areas in Idaho, Washington, and Oregon was conducted to
determine the occurrence of cucumber mosaic virus (CMV), recently reported
to be seedborne in beans. Some 259 plants, sampled from breeding
lines of diverse germplasm, were found by enzyme-linked...
The objective of this study was to characterize an unknown agent associated with decline in black raspberry (Rubus occidentalis) in Oregon. A virus was found consistently associated with decline symptoms of black raspberries and was named Black raspberry decline associated virus (BRDaV). Double stranded RNA extraction from BRDaV-infected black raspberry...
Controllable parameters in a power system include generator
terminal voltage, generator input power and network admittances.
These parameters can be controlled to damp
mechanical rotor oscillation in the generators and thereby
improve system transient stability. Explicit equations are
derived in this thesis for the control of these parameters to
introduce...
Published December 1893. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Studies were conducted to examine the effects of feeding
injury by the twospotted spider mite (Tetranychus urticae
Koch) on physiological processes of its host plant, peppermint
(Mentha piperita L.). Aspects of mite-induced host plant
physiological stress that were studied included: 1) effects of
injury on plant-water relations; 2) photosynthesis and...
Mycobacteriosis is a common disease of laboratory zebrafish (Danio rerio). Different infection patterns occur in zebrafish depending on mycobacterial species. Mycobacterium marinum and M. haemophilum produce virulent infections associated with high mortality, whereas M. chelonae is more wide spread and not associated with high mortality. Identification of mycobacterial infections to...
The microsporidian parasite, Pseudoloma neurophilia, is the most commonly diagnosed infectious disease in laboratory populations of the zebrafish, Danio rerio. Infections by P. neurophilia are generally subclinical, however, they can become acute either incidentally or due to experimental immune suppression. Non-protocol induced variation can confound results in laboratory experiments using...
This study describes and quantifies some microprocesses of malaria
transmission including blood vessel location by Anopheles stephensi and
sporozoites delivery of An. stephensi infected by Plasmodium berghei. The
study models the effects of malaria parasite-induced changes in probing
behavior and mosquito mortality on disease transmisson. Finally, host, vector,
and parasitological...
Hearing loss is one of the most common defect, affecting 360 million people worldwide due to several factors including congenital, present at or soon after birth or acquired with age. Congenital hearing loss affects 32 million children in the world. The economic impact of hearing loss is estimated to cost...
Eola rasp leaf of cherry was first described by Milbrath and
Reynolds in Oregon in 1961. Dr. Cadman of the Scottish Horticultural
Research Institute suggested that this disease was incited by a strain
of tomato ringspot virus (TomRSV), but since then controversial results
with some isolates of EoIa rasp leaf...
A series of studies was conducted to determine the presence
of tobacco rattle virus (TRV), potato virus X (PVX), and other
viruses in wild plants and to evaluate the efficacy of the detection
methods; to characterize and purify an isolate of TRV; and
to study the interaction between TRV and...
Published May 1978. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Viability and dispersal of ascospores of Anisogramma anomala, the cause of eastern filbert blight (EFB) on European hazelnut, from diseased branches pruned from trees were measured. In each of two years, branches bearing stromata of A. anomala were cut in mid-December and compared to branches cut near budbreak in March,...
The marked movement of utilizing Oregon's water power
in the service of generating electric current, has been promoted
by the economics in transmission of electricity to distances
both great and small; by the harnessing of industrial
implements to electric power; and by the advancement and extension
of interurban railways.
It...
A rotating, flat plate condensation experiment has been developed to
investigate the heat of the Rotating Bubble Membrane Radiator (RBMR). The
RBMR is a proposed heat rejection system for space applications which uses
working fluid condensation on the inside surface of a rotating sphere to
reject heat to space. The...
Green manures, soil solarization, and long rotations with crops not susceptible to Verticillium wilt are among the disease management tactics currently under investigation as alternatives to chemical fumigation of soil. The effect of a broccoli green manure on soil microsclerotial populations of three isolates of Verticillium dahliae and on Verticillium...
Published August 1925. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Abundant conidial and sclerotial production occurs on iris
plants infected with Botrytis convoluta Whetzel and Drayton during
the cool moist months of the year. Experiments were designed to
study the survival and inoculum potential of conidia and sclerotia.
Basic nutritional requirements of the fungus in culture were also
studied.
Results...
The use of petroleum oil prevented, to varying degrees: the
transmission of three stylet-borne viruses in three different crops.
The use of oils resulted in a marked improvement in the number of
lily bulbs harvested from treated plots as compared to the number of
lily bulbs harvested from untreated plots....
Published June 1932. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Previous work on the rose mosaic virus has produced uncertainty
concerning the identity and properties of this virus. This work was
undertaken to help establish the true identity of the virus and to determine
some of its properties.
A mechanically transmissible virus associated with rose mosaic
virus disease of Rosa...
Published May 1931. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Published October 1978. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Winter squash (Cucurbita maxima) grown in Oregon’s Willamette Valley for edible seed, frozen foods, and fresh markets is susceptible to an undiagnosed soilborne disease. Diseased squash fields exhibit symptoms of stunting, root and crown rot, vascular discoloration, and late-season wilt, which in extreme cases can lead to total crop failure....
Several bean yellow mosaic virus (BYMV) strains, presumably
not transmissible by aphids, were studied to determine the biological
and environmental conditions which would possibly result in aphid
transmission of these strains. Investigations were made to study the
effect of different aphid rearing conditions on the transmission
frequency of BYMV. Also,...
Root-knot nematodes were among the earliest plant-parasitic
nematodes to be recognized. Before 1949, they were considered as the
one species Heterodera marioni (Cornu 1887) Goodey 1932. In 1949
Chitwood completed a taxonomic study of the root-knot nematodes and
placed them in a separate genus Meloidogyne. Economically they are
one of...
The influence of oil sprays on the field spread of the aphid-borne
bean yellow mosaic virus (BYMV) in bean was studied in 1972
and 1973. Oil sprays failed to significantly reduce virus spread in
the 1972 BYMV experiment. However, the data did suggest that the
efficiency of the oil sprays...
Preliminary studies were run to determine the sensitivity and
reliability of enzyme-linked immunosorbent assay (ELISA) for the
detection of potato virus X (PVX). ELISA was found to be capable of
detecting PVX in tobacco at a 1:3333 sample dilution. The reliability
of ELISA for the detection of PVX in potato...
Raspberry bushy dwarf virus (RBDV) is the sole member of the idaeovirus genus of plant viruses. It is a pollen-borne virus that economically impacts both red and black raspberries worldwide. Three strains of the bipartite RBDV have been reported. The common strain found in North America, South America, Australia, New...
Pallidosis is a disease of strawberry identified in 1957 with an unknown etiology. Two previously uncharacterized viruses in strawberry, Strawberry pallidosis associated virus (SPaV) and Beet pseudo-yellows virus (BPYV), have been found associated with disease symptoms. The complete nucleotide sequence of both viruses was determined and molecular detection protocols developed....
Published July 1943. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Published July 1940. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Observations of annual growth and size and color of leaves and fruit are helpful in determining fertilizer needs. In addition, leaf analysis
indicates which elements are present in adequate, deficient, or excessive amounts. Soil analysis is useful in predicting the need for lime applications. Suspect a nutrient deficiency if poor...
El cultivo de plantas ornamentales, frutas o
legumbres puede ser una experiencia maravillosa a
menos que las plantas se enfermen y mueran. Estas
plantas se consideran enfermas. Muchas cosas pueden
causar que las plantas se enfermen, entre ellas agentes
bióticos (vivos), abióticos (inertes) o una combinación
de los dos. El...
Many garden and landscape plants
are susceptible to one or more plant
diseases. Diseases can reduce the yield
of fruit and vegetable crops and disfigure
ornamental trees, shrubs, and
flowers.
Three viruses were isolated from dahlias using a modification of
Yarwood's leaf-disc method of inoculation. Two of these isolates have
been reported previously in dahlias. In addition, a fourth virus was
isolated using a liquid-nitrogen transmission technique.
Dahlia virus isolate 1 possessed host range and thermal inactivation
properties similar to...
Recent investigations indicate that several latent viruses of
apples exist in common commercial apple stocks, but these viruses
and their relationships are incompletely understood. This thesis
describes investigations of crab apples as indicators of latent viruses
of apples.
Eighty-eight varieties and species of crab apples were tested
as indicators of...
A necrosis at the tip of cones was observed on hop (Humulus lupulus), cultivar "Nugget", grown in Oregon in the early 1990's. Fusarium sambucinum and F. avenaceum were recovered from symptomatic cones in 1998 and preliminary inoculation experiments suggested both Fusarium species could cause hop cone necrosis. Studies were carried...
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...
Seed piece to plant transmission of the potato late blight pathogen, Phytophthora infestans, occurred with isolates of the clonal lineages US-8 in Oregon and US-11 in Washington in field trials. Average transmission rate across potato cultivars was 0.5 and 2.4% with US-8, and 0.8 and 1.0% with US-11 in 1999...
The inheritance mode of pea-resistance to the Lentil
Strain of Pea Seedborne Mosaic Virus (PSbMV-L) was
studied. In addition, commercial pea cultivars, Plant
Introduction (P.I.) lines and Oregon State University
(OSU) breeding lines were tested for susceptibility to
this virus. These lines were also tested for their
reaction to Bean...
Published March 1974. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Published June 1974. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Published August 1938. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Published June 1966. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
The effects of scald epidemics, induced by Rhynchosporium secalis
(Oud.) Davis, on the yield and quality of winter malting barley have not been
reported. The principal objective of this investigation was to assess yield and
quality losses in resistant and susceptible winter barley genotypes in diverse
environments of the Pacific...
Lily hybrids vary in their ability to produce
virus-free (VF) bulblets when grown from virus-infected
scales in tissue culture. Asiatic hybrids typically
produce a higher percentage of in vitro VF scale bulblets
than do Lilium longiflorum cultivars. Three hypotheses
concerning the cause of this variation are tested on five
lily...
Bacterial canker, caused by Pseudomonas syringae pv. syringae is
recognized as one of the greatest limiting factors in cherry production
in Oregon. Disease incidence may be decreased when susceptible
cultivars are high-grafted onto tolerant/resistant rootstocks. This
research was begun to develop a rapid screening method which could be
used to...
Published April 1926. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Phytophthora ramorum is a plant pathogen that was accidentally introduced to the United States. This invasive microorganism has killed over a million trees in California and Oregon, and continues to spread to new areas. Diseased areas have been nationally quarantined to prevent further spread and more than ninety countries include...
This publication discusses the environmental requirements of needle diseases, their potential impact on tree vigor, when disease levels signal a problem, and what you can do to minimize damage.
This study was conducted to investigate why root disease centers east of the
Cascade crest tend to be larger in diameter and more abundant than their counterparts to
the west, within subalpine forest stands of central Oregon. The trend in a 290 km² study
area appeared opposite of what was...
The effects of soil moisture, mineral nutrition and
temperature on the susceptibility of peas to inoculation
with bean yellow mosaic virus (BYMV) by the green peach
aphid, Myzus persicae (Sulz.) were investigated along with
three vector-virus relationships. In addition, a comparative
study was made of two methods of evaluating susceptibility...
Take-all root rot (caused by Gaeumannomyces graminis var.
tritici, Ggt) is one of the major diseases limiting winter wheat
yields in western Oregon. Losses caused by take-all (TA) can be
significantly reduced through crop management and fertilization
practices.
Results from field experiments in western Oregon show that the
use of...
Pyrenophora tritici-repentis, causal agent of tan spot of wheat, produces multiple
host-selective toxins (HSTs), including Ptr ToxA, encoded for by ToxA, Ptr ToxB,
encoded for by ToxB, and Ptr ToxC. Variable distribution of these three HSTs among
different isolates of P. tritici-repentis, both singularly and in all possible combinations,
defines...
The Feldmannia sp. virus is a large icosahedral virus that persistently infects
marine brown alga Feldmannia sp.. So far, there is no information available about
viral genome replication, gene structure and gene expression in this unique viral-host
system. The purpose of this study was to characterize the general features of...
Victoria blight of oats is caused by the fungus Cochhobolus victoriae. This fungus is pathogenic due to its ability to produce the host-selective toxin victorin. Previously, a 100-kD protein that binds victorin in vivo only in susceptible genotypes was identified as
the P protein of the glycine decarboxylase complex (GDC)....
Although chemical fungicides are commonly used to control fungal soil-borne
diseases of Easter lilies, Lilium longiflorum Thunb., in field production and
greenhouse forcing, cultural and biological controls may be alternatives or
complementary to chemicals for control of pathogens.
The influence of inoculations with beneficial, symbiotic, and biocontrol
microorganisms to enhance...
There are several grape disorders that reduce fruit
set. One, millerandage, is from poor fertilization to
produce "hen and chicken" or small seedless berries; while
another, Coulure, is the failure of grape flowers to
develop into berries. A third one, inflorescence necrosis
(INec), is a disorder that should be in...
Bacterial contamination is one of the most important problems
both in plant tissue culture research and commercial laboratories. Early
detection of contaminants saves time, effort, and money. Strawberry
runner explants were screened for contaminants during June to August,
1994 and 1995. Most contaminants found were bacterial rather than
fungal. Bacterial...
Fluctuations in population density of Pratylenchus sp.,
Trichodorus sp., and Xiphinema americanum s. 1. in three blueberry
fields were determined monthly for one year. Pratylenchus densities
were greatest in August and least in October. Three distinct
periods of population growth occurred; during January, April, and
between June and August. Trichodorus...
Crown gall disease is caused by the ubiquitous soil bacterium Agrobacterium tumefaciens which transfers a portion if DNA (T-DNA) into the plant cell. Preventing infection by using the biocontrol strain Agrobacterium radiobacter K84 is currently the only defense for crown gall. Two different resistance strategies were examined in this work....
Nematodes are roundworms with complex organ systems. They occur worldwide in all environments. Most species benefit agriculture by contributing to decomposition of organic matter and are important members of the food chain. Some species are parasitic to plants or animals. More than 2,000 of the 20,000
identified nematode species are...
Published June 1930. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
A comprehensive approach to nutrient management will help you ensure availability of optimum levels of nutrients for tree growth. Components of a comprehensive nutrient management strategy include:
• Soil analysis before planting (useful in predicting the need for potassium, magnesium, or lime applications)
• Observations of annual shoot growth, leaf...
Published January 1966. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
The primary goal of this dissertation research was to assess the use of compost for the control of several foliar and soil borne diseases commercially important in the Pacific Northwest. The use of compost teas to control of gray mold (Botrytis cinerea) on geraniums, powdery mildew (Podosphearapannosa var. rosae), rust...
Tall fescue is thought to have co-evolved with the fungal endophyte Acremonium coenophialum to form a mutualistic relationship. Endophyte-infected (EI) plants can have increased growth and survival when compared with endophyte-free (EF) plants. Responses to endophyte-infection vary and are host-genotype and fungal-biotype specific. Mechanism(s) by which endophyte-infection confers increased growth...
From July, 1982 to August, 1983 I had the privilege of serving an internship
as an oceanographer at the National Marine Fisheries Service Beaufort
Laboratory. During the period of my appointment I assisted in a preliminary
assessment of the potential fishery impacts of ocean thermal energy conversion
(OTEC) power plants....
Victoria blight, caused by fungus Cochliobolus victoriae, is a disease originally described on oats and recapitulated on Arabidopsis. Victoria blight is used as a model plant disease that conforms to an inverse gene-for-gene interaction. C. victoriae virulence is dependent upon its production of victorin, a host-specific toxin that induces programmed...
Treating styroblock containers in hot water (68°C) with a very dilute bleach and detergent solution effectively reduced populations of Fusarium and Cylindrocarpon spp., two potential root pathogens of containerized conifer seedlings. However, the treatment did not significantly reduce levels of Phoma (another potential pathogen) nor saprophytic Penicillium and Alternaria spp....