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A Biosystematic Study Of Heterotheca Section Pityopsis, Frank D. Bowers

Doctoral Dissertations

A biosystematic study of the section Pityopsis of the genus Heterotheca was undertaken. Cytological, morphological, chromatographic, and hybridization studies were utilized to provide a basis for taxonomic treatment of the taxa. The species were divided into two broad groups; the Heterotheca graminifolia group (H. adenolepis, H. aspera, H. graminifolia, H. microcephala var. microcephala and var. aequilifolia, and H. oligantha) and the H. pinifolia group (H. falcata, H. flexuosa, H. pinifolia, and H. ruthii) Heterotheca ruthii appears to be intermediate between the two groups and is closely related to H. oligantha.

Cytology indicates the diploid species (N=9) …

Field Studies Of Selected Pathogens For The Control Of The Corn Earworm, Heliothis Zea Boddie, W. Robert Tilyard Jr.

Masters Theses

Tests conducted at the University of Tennessee were designed to compare the control results of the corn earworm by three different pathogens and a standard chemical insecticide. Also, some methods of application were tested. The pathogens tested were a bacterium, Bacillus thuringiensis Berliner, a nuclear polyhedrosis virus specific for Heliothis zea, and the nematode, DD-136.

The treatments were applied under field conditions directly to the ears of corn.

The results indicated that general effectiveness is based on how accessible the pathogens are to the earworm larvae. Best control was accomplished by a treatment using a virus-nematode combination. That treatment …

Dry Matter And Nutrient Dynamics In Red Spruce-Fraser Fir And Yellow Birch Ecosystems In The Balsam Mountains, Western North Carolina, George T. Weaver

Doctoral Dissertations

Introduction: The present study seeks to estimate and compare rates of annual net primary production and flux of four macronutrients in contrasting high elevation Pica rubens-Abies fraseri (spruce-fir) and Betula lutea (yellow birch) ecosystems and to relate variations of net production and nutrient flux to certain site and stand structural parameters. The study was conducted at elevations between 1524 and 1954 meters in the Balsam Mountains of Western North Carolina. Biomass and pools of calcium, potassium, magnesium, and phosphorus were determined in each of five vegetational strata, the forest floor, and the solum. Net production of dry matter and nutrient …