The root disease fungus Inonotus tomentosus, common in the old
growth boreal forests of British Columbia, poses a threat to the
health of second growth forests established on sites with a previous
history of root disease. Colonized stumps occur in groups of 1 to 6;
the groups are clumped within...
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,...
An isolate of Coniothyrium obtained from a stem canker on
Nocturne rose from the Botany Department Farm, Corvallis, Oregon
was studied with respect to morphological and cultural characters,
pathogenicity and mineral nutrition. The hyphae of the isolate were
smooth, septate and branched. The hyphal cells averaged 16.37 X
3.52 microns....
An important disease of Vitis vinifera production in Oregon and all other commercial growing regions is powdery mildew of grape, caused by the obligate fungal pathogen Uncinula necator (Schwein.) Burril. Grape production can be characterized as a long-term investment in the establishment and maintenance of the vineyard. Establishment times have...
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 effects of fenamiphos on soil and root populations of Pratylenchus penetrans were evaluated in four red raspberry cv. Willamette fields in Northwestern Oregon. Field 1 was a silty clay loam with 53% organic matter (OM). Field 2 and 3 were silty loam soils with 3.25 and 2.55% OM, respectively...
The efficiencies of wet sieving/sucrose
centrifugation (WS/SC) recovery of Pratylenchus penetrans
(59 %), Paratylenchus sp., (80 %), and Criconemella
xenoplax (66 %) were established. Baermann funnels (BF)
recovered significantly more P. penetrans (p = 0.01) and
significantly less (p = 0.01) C. xenoplax than did WS/SC.
While densities of P....
The genus Phytophthora contains some of the most destructive pathogens of forest trees, including the most destructive pathogen of alder in recent times, Phytophthora alni. Alder trees were reported to be suffering from canopy dieback in riparian ecosystems in western Oregon, which prompted a survey of alder health and monitoring...
