Three Oregon soil types (Chehalis silt loam (CSL), an alluvial
soil from the Willamette Valley; Ayre sandy loam (ASL), a volcanic
pumice soil from the Central high desert; and Klamath fine sandy
loam (KFSL), a basaltic mineral soil from the Klamath Basin) were
collected adjacent to fields which had been...
Race identification of stripe rust (Puccinia striiformis West. )
is influenced by environment, pathogen variability and host age.
Isolates of stripe rust were collected in the Pacific Northwest and
characterized on two sets of differential varieties; the "Oregon" and
the United States. Six of the seven isolates tested on the...
The virulence of 44 isolates of stripe rust (Puccinia striiformis
West.) from 33 collections made during 1971 and 1972 were characterized
on two sets of differential varieties. The varieties in the
"Oregon" set were: Cappelle Desprez, Chinese 166, Dippes Triumph,
Druchamp, Etiole de Choisy, Flamingo, Gaines, Golden, Ibis, Leda,
Michigan...
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...
A study was conducted to determine the influence of DMSO
(dimethyl sulfoxide) on suberization and wound periderm formation
in cut potato tuber tissue, and to determine the effectiveness of
DMSO as a potato seedpiece treatment for prevention of seedpiece
decay in the field. The influences of tuber storage conditions,
varieties,...
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...
Abundant conidial production occurs from colonized straws and
plants infected with Cercosporella herpotrichoides Fron during the
cool moist months of the growing season. Experiments were
designed to study the survival, inoculum potential and competitive
saprophytic ability of conidia in soil.
Laboratory results indicated that cool moist soil favors the
saprophytic...
The physiologic specialization of nine isolates of stripe rust
(Puccinia striiformis West.) collected in the Pacific Northwest
was determined. The separation of races was based on the differential
susceptibility of the following wheat varieties: Cappelle
Desprez, Chinese 166, Dippes Triumph, Druchamp, Etoile de
Choisy, Flamingo, Gaines, Golden, Ibis, Leda, Michigan...
The primary cause of "early dying" disease of potatoes in
Oregon is Verticillium dahliae; however, Colletotrichum atramentarium,
Erwinia carotovora subsp. carotovora (Ecc) and E. carotovora
subsp. atroseptica (Eca) are also commonly isolated from
diseased plants. Therefore, field and greenhouse studies were
initiated to determine the relative involvement of each pathogen,...
Spore dispersal gradients and pod disease gradients from point
inoculum sources of Botrytis cinerea were measured over time in two
snap bean field experiments. Laboratory grown inoculum was placed
at ground level in a 30 x 30 cm square at bloom initiation and
removed at full bloom. Dispersal of inoculum,...
The use of fungicides for the control of foot rot of winter
wheat, caused by Pseudocercosporella herpotrichoides (Fron) Dei.,
requires a forecast of disease risk to optimize this management
practice ecologically and economically. Foot rot occurs in both
the mild, wet (100+ cm, ppt./year) annual cropped areas in western
Oregon,...
Field microplot studies conducted over two seasons
(1982-1984) evaluated the influence of four physically and
chemically diverse soils collected from Pacific Northwest
wheat fields on the incidence of dwarf bunt of winter
wheat caused by Tilletia controversa Kuhn. These soils
were placed at Flora and Pendleton, Oregon to determine
the...
Field plots of cv. Russet Burbank potatoes from a
single seedlot were established at four sites over two
seasons (1985-86) in two locations in Oregon to determine
the role of water-borne inoculum of Erwinia carotovora in
plant infection. One site at each location was irrigated
from a surface-water source and...
Isolates of Trichoderma spp. collected from snap bean foliage were tested for inhibition of grey mold of snap beans caused by Botrytis cinerea. In a detached blossom-pod assay an isolate of Trichoderma hamatum reduced pod rot by 94% compared to the nontreated check. Control was comparable to that obtained with...
Population size of Clavibacter michiganensis subsp.
sepedonicus in potato cv Russet Burbank and plant response
as affected by drought were assessed in a greenhouse
experiment. Water deficit stress and no stress treatments,
and inoculum densities of 0 or 2 X 10⁷ cfu C. m.
sepedonicus/seed piece were arranged factorially. Stem...