Thesis (Ph.D.)--University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (April 26, 2007) Vita. Includes bibliographical references.

Thesis (Ph. D.)(Plant Production)--University of Pretoria, 2000. / Title from opening screen (viewed Oct. 6, 2002). Includes bibliographical references.

Thesis (Ph.D.) -- University of Adelaide, Dept. of Plant Science, 2001. / Bibliography: leaves 220-247.

Thesis (MTech (Horticulture))--Cape Peninsula University of Technology, 2018. / Global demand for environmentally-friendly grapevine cultivation and pest control has necessitated an improved understanding of the relationship between soil properties and beneficial naturally occurring antagonists like entomopathogenic fungi (EPF). This group of fungi presents a viable alternative for the control of destructive pests such as the grapevine mealybug. Sixty-six soil samples were collected from 22 vineyards in the Western Cape, South Africa. The association between soil nutrient status and EPF prevalence was then examined. Fungi were isolated with methods of insect baiting and selective media. Fungal strains were identified and characterized using light microscopy and DNA analysis (ITS and BTub). In addition, fungal isolates were tested against a key grapevine pest, Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae) using an immersion bioassay at a concentration of 1 x 108 conidia ml-1. Twenty-three fungal strains were isolated and correspondence analysis (CA) of data indicated a positive association between fungal occurrence and moderate to high levels of soil-based macronutrients. Binomial logistic regression analysis revealed that soil N, K, Ca, Mg and S concentrations and C/N ratio were correlated with at least one EPF species. This study showed that some soil nutrient properties correspond to greater occurrence of EPF in grapevine soils. Strains of Beauvaria bassiana (Hypocreales: Clavicipitaceae) caused the highest mortalities (82% to 87%). In chapter three, I examined the effect of B. bassiana inoculation of grape plants on the infestation level of P. ficus, and the growth and volatile constituents of potted grape plants. The grapevines were inoculated with 1 x 108 conidia ml-1 of B. bassiana by drenching before experimentally infesting them with thirty P. ficus adult females. At four weeks post treatments, the fungus was re-isolated from leaves of 50% of the fungus exposed plants. No significant difference (P > 0.05) was observed in all the plant growth parameters measured in the fungus treated and control plants. Plant tissue analysis revealed markedly higher contents of Ca and Mg in leaf tissue of plants exposed to the B. bassiana relative to the control. GC-MS analyses showed that a significantly (X2=5.1; P<0.02) higher number of known anti-insect volatile compounds (9) including napthtalene were present among fungus treated plants compared to the control plants (5). However, B. bassiana did not have any significant effect on total polyphenol, alkaloid and flavonoids. Overall, treatment with fungus did not offer any protection against infestation of P. ficus. In conclusion, this is the first study to report on the isolation of indigenous entomopathogenic fungal (EPF) strains within vineyards of the Western Cape. The study revealed that inoculating grapevine plants during cultivation had a net positive effect on the production of volatile compounds in grapevines. These findings shed light on the mechanisms involved in endophytic fungus-plant-insect interactions. This study contributes valuable information to future development of ecological approaches involving EPF for insect control in vineyards and in general, agricultural settings.

Bibliography: leaves 220-247.

Bibliography: leaves 220-247. / x, 247 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Plant Science, 2001

Thesis (Ph.D.) -- University of Adelaide, Dept. of Agronomy and Farming Systems, 2002. / "September 2001" Includes bibliographical references (leaves 206-230).

No description available.

"September 2001" Includes bibliographical references (leaves 206-230)

"September 2001" / Includes bibliographical references (leaves 206-230) / xviii, 230 leaves : ill., plates ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Agronomy and Farming Systems, 2002