Entomopathogenic fungi are cosmopolitan microbial pathogens that cause fungous diseases in a wide range of insects via spore infection. Due to their natural enemy status, they have tremendous potential for use as microbial control agents against insect pests, especially subterranean pests for which few management options are available. The clover...
We evaluated genes previously identified from a large scale functional genomics screen for their potential value to help enhance carbon sequestration in planted trees. We used poplar as a model tree species because of its abundant genetic variation, ease of gene transfer, and availability of large databases for genomic, anatomical,...
Orchardgrass (Dactylis glomerata L.) is an important seed crop, but unlike other cool-season perennial grass seed crops such as perennial ryegrass (Lolium perenne L.) and tall fescue [Schedonorus arundinaceus (Schreb.) Dumort.], seed yields have not increased over time so there is considerable room for improvement. Research suggests that plant growth...
The climate of the Pacific Northwest is in flux, and existing forest ecosystems are stressed and poised to shift in fundamental ways, with or without human intervention. This dissertation probes the nature of forest responses to environmental change through investigations of morphology and genetics of three species of alder co-occurring...
Drosophila suzukii (Diptera: Drosophilidae), is a serious pest in soft and stone fruit industries worldwide. The unique serrated ovipositor of female Drosophila suzukii allowed the species to reproduce in intact, ripening fruit before the harvest. Current control methods rely heavily on insecticide application, only becoming less profitable due to the...
The goal of this dissertation is to examine the effectiveness of high intensity-short duration goat browsing for the control of Himalayan blackberry (Rubus armeniacus) and English ivy (Hedera helix), two widespread noxious weeds in the Pacific Northwest.
The effects of goat browsing on Himalayan blackberry vigor, as quantified by densities...
Douglas-fir (Psudotsuga menziesii (Mirb.) Franco) seedlings were outplanted on eight dates (every three weeks from mid-August 2005 through mid-January 2006). On each plant date, seedlings from a conventional dormancy (CONV) induction treatment, including moisture and nutrient stress, and a shortened daylength (SD) treatment were outplanted on three western Oregon sites...
Two experiments were conducted to evaluate the influence of a yeast-derived cell wall preparation (YCW) on forage intake and digestibility, ruminal fermentation characteristics, serum prolactin and prolactin stores, and milk production in beef cattle consuming high-alkaloid tall fescue straw. In Exp. 1, 16 Angus x Hereford ruminally cannulated steers (200...
Quantitative resistance (QR) to disease is usually more durable than qualitative resistance, but its genetic basis is not well understood. We used the barley/barley stripe rust pathosystem as a model for the characterization of the QR phenotype and associated genomic regions. As an intermediate step in the preparation of near-isogenic...
One of the most economically important genes in squash (Cucurbita spp.) is the B gene which conditions precocious depletion of chlorophyll in preanthesis fruit. The B genes are found naturally occurring in at least three of the five domesticated species of Cucurbita, including C. pepo, C. maxima and, most recently...
Grasslands in the Pacific Northwest are characterized by seasonally wet, acidic soils that mainly support cool season grasses and a limited number of legume species. A major limitation to efficient animal production in grass-dominant pastures is the decline in the herbage growth rate and nutritional quality of forage from late...
Xanthomonas hortorum pv. carotae (Xhc) is an epiphytic, plant pathogenic bacterium that causes the disease bacterial blight of carrot (Daucus carota subsp. sativus). Infection with Xhc can result in blighting of leaves and umbels and reduce quality and yield of carrot seed crops. Carrot production in the United States approaches...
This study investigated the effects of diversification strategy through the inclusion of forb and legume based pastures in the feedbase of dairy cows on annual forage production, botanical composition, spring milk yield, N partitioning and methane emissions from dairy cows in Western Oregon. Using a randomized complete block design, 3...
This thesis consists of three manuscripts addressing separate components of barley breeding, plus an introduction and a conclusion summarizing the status of barley in the Pacific Northwest, plus the implications of the research presented in this thesis. In the first manuscript, a package written for the statistical software "R" that...
The following experiment presented herein compared growth, physiological, and reproductive responses of beef heifers with (MI) or without (CON) access to a creep-feeder, as a manner to stimulate metabolic imprinting while nursing their dams. On d 0 of the experiment, 60 Angus × Hereford heifers were ranked by initial BW...
Controlling competing vegetation with the application of herbicides and increased seedling size at planting has been shown to increase seedling survival and growth. These two important reforestation tools have often been studied independently of each other, limiting comparisons that can be made between them. This study utilized a factorial treatment...
Two studies were conducted to evaluate the influence of supplement composition on intake and digestibility of a low-quality (< 6% CP), cool-season forage, as well as cow performance. Treatments included a non-supplemented control (CON), corn (approximately 8% CP), corn and urea (LU = corn + 0.09 mg/kg BW urea, approximately...
In arid and semi-arid deserts, soils are commonly covered with biological soil crusts. The
study of arid biocrusts and their ecological function has become increasingly common in
the literature over the last several decades. Interestingly, no mention is made of
biological soil crusts in forested ecosystems, raising the question as...
Limnanthes floccosa ssp. floccosa and L. floccosa ssp. grandiflora are two of five subspecies of Limnanthes floccosa endemic to vernal pools in southern Oregon and northern California. Three seasons of monitoring natural populations have quantified that L. floccosa ssp. grandiflora is always found growing sympatrically with L. floccosa ssp. floccosa...
Concern over the increasing proportion of juvenile wood grown in second growth plantations has led to a large amount of research on the effects of common silvicultural practices on wood quality. Lacking is research on the effect of timing and
duration of vegetation control on wood quality near the pith...