Treesearch

Seeds were collected from locally and naturally grown Chinese tallow trees (CTT) and characterized for general physical and chemical properties and fatty acid composition of the lipids. The effects of four different solvents (petroleum ether, hexane, diethyl ether, and 95 % ethanol) and two extraction methods (supercritical carbon dioxide (SC-CO2) and conventional Soxhlet) on the properties of the CTT seed oil, including Chinese vegetable tallow (CVT) and stillingia oil (SO), were also investigated. In general, the yields of CVT and SO did not vary based on solvent for Soxhlet extraction...

Due to the aquatic nature of oomycetes, Phytophthora spp. can be found in a wide variety of waterways in and around natural and agricultural ecosystems—including forest streams, urban streams, and irrigation ponds. They are disseminated effectively and efficiently in flowing water, so Phytophthora spp. can be moved readily from an infested area (e.g., a nursery) to nearby non-infested environments if waterways in the infested area become contaminated with propagules of the pathogen. This type of dissemination—particularly for exotic species like P. ramorum—poses a serious threat to plants...

A group of biomass-derived lignins isolated using organosolv fractionation was characterized by FT-IR spectral and thermal property analysis coupled with multivariate analysis. The principal component analysis indicated that there were significant variations between the hardwood, softwood, and grass lignins due to the differences in syringyl and guaiacyl units as well as the different processing temperatures and times used to isolate the lignins. Partial least squares regression revealed that the concentration of syringyl units was the foremost factor behind the variation in glass transitio...

Twenty 70-year-old longleaf pine trees from a spacing, thinning, and pruning study were harvested, from which samples were analyzed for gross calorific value (GCV). A strong correlation was found between GCV and extractive contents for the unextracted wood samples. Although lignin content should impact GCV, no correlation was found between the variation in GCV with lignin content for the extractive-free wood samples. Mid-IR spectroscopy coupled with multivariate analysis provided strong correlations between the mid-IR-predicted and calorimetry- determined values for the unextracted wood...

In Oregon, efforts to eradicate Phytophthora ramorum from forested areas have included use of herbicides to kill infected plants. Use of herbicides on disease-infected plants leads to various outcomes, from decreased spread of disease to greater spread of disease, depending on the plant-pathogen system being examined. In this study, viburnum (Viburnum) cuttings, rhododendron (Rhododendron) cuttings, and chestnut oak (Quercus prinus L.) seedlings were treated with herbicides at standard application rates for woody shrubs 4 days after their roots had been infected with P. ramorum. The amount...

The objective of our research was to determine the environmental conditions and lesion age favorable for Phytophthora ramorum sporulation under field conditions. For 2 years, new camellia, rhododendron, and California bay laurel (Umbellaria californica (Hook. & Arn.) Nutt.) nursery stock were seasonally inoculated (every 3 months) on foliage. They were covered overhead to prevent rainfall from falling on the plants, but otherwise the plants were completely open to the natural environment. Consistent leaf wetness periods were produced with overhead misting systems and controlling sensors to...

Once Phytophthora ramorum is introduced into a nursery on a host, its local spread and establishment is primarily dependent on sporangia and zoospore production. Nursery operators commonly use fungicides to prevent the establishment of Phytophthora –caused diseases, although current research only supports the use of fungicides for preventing infection. It is still unknown, however, what effect fungicide treatments have on sporulation, spread, and persistence of the pathogen on established infections. With this additional knowledge, fungicide treatments could be more effectively used to...

The objective of this work was to establish inoculum density relationships between Phytophthora ramorum and selected hosts based on whole plant inoculations. Knowledge of levels of initial inoculum needed to generate epidemics is needed for disease prediction and development of pest risk assessments. Sporangia of six P. ramorum isolates representing the NA1 and EU1 clonal lineages were produced by incubating 20 percent V8- juice agar plugs containing mycelium, in 1 percent soil extract for 48 hours and adjusting the suspensions to 0, 50, 100, 500, 1,000, 2,000, and 3,000 sporangia/ml....