Commercial radish seed producers in the Willamette Valley of Oregon have observed a late season wilt in their seed fields. Twenty-two fields were surveyed for wilt in the Willamette Valley during June through August 2012 and 2013. Plants exhibiting wilt symptoms were collected from the fields and examined for vascular...
A study was conducted of the influence of various climatic and
soil factors on the development of onion pink root disease and of the
influences of temperature, light, pH, carbon and nitrogen sources,
and vitamins on the growth in vitro of an Oregon isolate of the pink
root fungus, Pyrenochaeta...
Pleuropogon oregonus Chase is a rare wetland grass endemic to eastern Oregon. The species is composed of two widely separated populations, one in Lake County and one in Union County. In order to reduce the risk of extinction, the Oregon Department of Agriculture Native Plant Conservation Program initiated several reintroduction...
Arctostaphylos viscida Parry and A. canescens Eastw.,
two well-known and frequently encountered manzanitas in the
Siskiyou Mountains in southwestern Oregon, are shown to
hybridize and to produce an extensive series of morphological
intermediates. The hybridization occurs wherever populations
of these two species meet at contact zones of
serpentine and non-serpentine...
Corydalis aquae-gelidae is a large herbaceous perennial
in the Fumariaceae that has high habitat specificity. It is
endemic to the western Cascade Range of Oregon and
Washington, almost entirely on the Mt. Hood and Gifford
Pinchot National Forests. It is a federal C2 candidate
under the Endangered Species Act and...
Cephalosporium stripe, caused by the soil-borne ascomycete Cephalosporium gramineum, is becoming an increasingly important disease of winter wheat (Triticum aestivum) in several areas of the world, especially where stubble mulch is practiced to maintain soil moisture and prevent erosion. As cultural control of the disease is infeasible and no fungicides...
Phaeocryptopus gaeumannii is a pathogenic fungus on Douglas-fir needles which has become a serious threat to timber production in the last decade along the Oregon coast This research was undertaken to describe the general biology and pathology of F. gaeumannii on Douglas-fir needles and how environmental variables affect fungal development....
Cephalosporium stripe of wheat (Triticum aestivum),
caused by the soilborne fungus Cephalosporium gramineum,
results in significant yield reductions in dryland winter
wheat crops of the U.S. Pacific Northwest. The
development of resistant cultivars offers the best hope
for disease control. Breeding for resistance is hampered
by the long trial times...
After an unusually high incidence of Fusarium canker was observed in commercial hop fields of the Pacific Northwest, field surveys were conducted and revealed that canker incidence ranged from 20 to 60% of bines sampled in six commercial fields, as well as wide-spread Hop stunt viroid infection in these six...
Infrageneric classification in Ribes has previously relied on a few, often
conflicting, morphological markers, such as spines, glands, and inflorescence
morphology. Suggestions that hybridization drives the evolution of the genus have
not been tested using phylogenetic methods. To assess the validity of infrageneric
classifications and the importance of hybridization to...