A potato plant growth and production model is developed with
the objectives of analyzing management alternatives and exploring
the nature of the early dying syndrome. The geographic area of
focus was the centerpivot irrigated circles of Oregon's Columbia
Basin. A problem analysis of the potato production system of this
area,...
A study of the host range and distribution of ticks and chiggers
(Acari) was undertaken in two contrasting forested areas of western
Oregon. Acarines were sampled from host mammals which were
trapped along line transects laid out in both areas, each consisting of
18 stations 50 feet apart. Hosts were...
Members of the family Simuliidae were studied in a single,
confined drainage system. In addition to determining the occurrence
and distribution of the species present, biological and ecological
observations were made. Specific measurements and observations
were accomplished to determine as much as possible about the habitat
specificity and life cycle...
The subsurface microbial biosphere in the igneous oceanic crust has implications for global geochemical cycling, early life on Earth, and the search for life on Mars. Microscopic evidence of a subsurface microbial ecosystem includes biotic alteration textures associated with basaltic glass. The exact conditions in the basaltic layer that make...
When Douglas-fir and red alder grow in mixture, interactions between the two species can be competitive, facilitative, or a combination of both over time. A number of factors have recently led to increased interest in managing these two species together for commercial production, and ongoing investigations are yielding important information...
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...
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...
Three methods--radial compression strength, color indicators of decay and micro-toughness, an examination of tracheid fracture patterns, were evaluated for detection of early decay and for application to field use. Three-eighth-inch diameter plugs 3/4-inch long, cut from the sapwood and heartwood of a Douglas-fir pole free of decay, were decayed by...