Non-target effects are one of the greatest potential risks of weed biological control programs, and understanding non-target effects of biological control at the population level is crucial for predicting when they will occur and altering the perception of biological control as a whole. In this thesis, we assessed the ecological...
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....
Managers of forest and plantation ecosystems are encountering growing problems involving plant pathogens and the expanding geographic ranges of these pathogens. Historically unexposed stands are exceptionally vulnerable when a non-native pathogen is introduced because these pathogens can cause devastating disease in a host population that lacks co-evolved resistance mechanisms. One...
Eight species of Lathvrus (Fabaceae, Faboideae) endemic to the
Pacific Coast of North America were the subject of a systematic
investigation. Taxa studied included Lathvrus vestitus, Nutt. ex T.
& G., L. laetif lorus Greene, L.. iepsonii Greene, £,. splendens
Kellogg, L. polvphvllus, Nutt. ex T. & G., L. holochlorus...
Many mycorrhizosphere microorganisms can produce
plant growth regulating compounds in vitro. Plant growth
regulating compounds are known to mediate root growth and
development. In reforestation practices, conifer tree
seedling growth and survival are linked to rapid root
growth and development after outplanting. Multifactorial
experiments were conducted to document variations in...
Radial colony growth of three isolates of Gliocladium roseum and three isolates of Bottytis cinerea were measured on 1/4 strength potato dextrose agar amended with concentrations of NaHCO₃ ranging from 0-2% (w/v). Compared to the control, reductions in colony diameter of the B. cinerea isolates ranged from 60-79% and 73-89%...
The reliability and sensitivity of enzyme-linked immunosorbent
assay (ELISA) in the detection of ilarvirus (isometric labile ringspot
virus) subgroup B and prune dwarf virus (PDV) isolates in Prunus and
Malus species has been well established. To use this technique in
large scale virus indexing programs more information was required on...
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...
I studied the water relations traits, twig conductivity, C'3 isotopic composition,
and wood density of three conifer and five angiosperm species in western Oregon. This
study took place from spring 2002 to fall 2003 on four sites. Species were selected to
represent the diversity of drought tolerance of woody plants...