This dissertation describes patterns in epiphytic macrolichen community composition along a nitrogen deposition gradient in the Yosemite region of the Sierra Nevada in California. This region is part of the largest federal air quality Class 1 designated air-shed in the western United States, covering the entire crest of the Sierra...
The sagebrush steppe ecosystem of the northern Great Basin is severely degraded and continues to decline due in large part to the invasive, non-native annual grasses Bromus tectorum L. (cheatgrass) and Taeniatherum caput-medusae (L.) Nevski (medusahead). Restoration of invasive-dominated areas is difficult, but can be enhanced by adding a carbon...
Four year old vines of 18 varieties were cane pruned, trained to a Scott Henry, thinned before veraison, and harvested in October and November 1993. Two of the varieties, Chardonnay and Cabernet Sauvignon, were used as standards. Only four varieties were spur pruned to reduce cropping or cluster size: Dolcetto,...
Seed size, abundance, viability, dormancy, and germination requirements strongly influence plant establishment and therefore are important considerations in restoration of native vegetation. These characteristics provide criteria for selection of suitable species, development of collection and pretreatment methods, and determination of seeding densities. The first set of objectives of this study...
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...
Phytophthora pini Leonian, recently re-established from P. citricola
I, is a pathogen with a wide range of forest and nursery hosts. It causes foliar
infections in horticultural nurseries in Oregon, where recirculating irrigation
systems are common. Increased use of recirculating irrigation systems may
contribute to disease caused by waterborne plant...
Verticillium wilt of hops in Oregon, caused by Verticillium
dahliae Kleb., was first reported in 1956. Later, V. albo-atrum
Reinke & Berth. was also isolated from infected hop plants, and thus
both species of the fungus were shown to be the causal agents of the
disease in Oregon.
The purpose...