Thesis (Ph. D.)--University of Missouri-Columbia, 1996. / Typescript. Vita. Includes bibliographical references (leaves 114-125). Also available on the Internet.

Thesis (Ph.D.)--University of Illinois, 2009. / Vita. Includes bibliographical references.

Thesis (Ph.D.)--University of Missouri-Columbia, 2004. / Typescript. Vita. Includes bibliographical references (leaves 123-133). Also available on the Internet.

Thesis (Ph. D.)--University of Wisconsin, 1967. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.

Thesis (M.S.)--University of Wisconsin--Madison, 1981. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph.D.)--University of Missouri-Columbia, 2004. / Typescript. Vita. Includes bibliographical references (leaves 123-133). Also available on the Internet.

The distribution and abundance of terrestrial snails which inhabit the Rocky Mountain bighorn sheep (Ovis canadensis Canadensis Shaw) ranges in the East Kootenay region of British Columbia were related to edaphic and climatic factors. Emphasis was placed upon those snail species which have been implicated as intermediate hosts of the sheep lungworm, Protestrongylus stilesi Dikmans. Retinella electrina (Gould), Euconulus fulvus (Muller), and Vitrina alaskana Dall were found to be widely distributed on all ranges and were present in all but the driest plant communities. On low elevation ranges, Euconulus is the most abundant but Retinellai.is the most widely distributed. In alpine regions, however, Vitrina is the dominant species. These hydrophilic species were found mainly on organic soils under leaf litter or logs in aspen and coniferous forest communities where moisture conditions were suitable. The relatively xerophilic species, Vallonia cyclophorella (Sterki), Gastrocopta holzingeri Sterki, and Pupilla muscorum (L.) are restricted to the dry, sandy soils of the bunchgrass communities, where they live under rocks. Of these species, Vallonia is the most abundant, but on the Columbia Lake range, Pupilla, which is restricted to this range, is almost as numerous. The clay and silt soils of the bitterbrush communities appear to be unsuitable for the survival of any snails. Wide temperature and moisture fluctuations, resulting in part from soil texture, appear to be the main factors limiting the occurrence of snails in these sites. With the possible exception of Vitrina and Pupilla, the distribution and abundance of snails on the East Kootenay sheep ranges can not be explained by variations in soil calcium, even though calcium was shown to affect reproductive and growth rates. Vallonia and Pupilla appear to be the most suitable intermediate hosts for sheep lungworm. However, no infected snails were found on any of the ranges and it was established that snails live in a habitat which is inaccessible to sheep. This indicates that terrestrial snails may not play a role in the life cycle of sheep lungworm in the East Kootenay region of B.C. / Science, Faculty of / Zoology, Department of / Graduate

The reniform nematode is a major pest affecting common upland cotton in the United States. Management of this pest in cotton fields only gives partial control and is sometimes neither economical nor profitable. Past research has shown no resistance to the reniform nematode in currently available commercial cotton cultivars. Screenings of several currently available cotton cultivars for tolerance to the reniform nematode were conducted in the growing seasons of 2006 and 2007 at the Delta Branch Experiment Station in Stoneville MS. Several cultivars were identified as tolerant and productive including ‘Croplan Genetics 3520 B2RF,’ ‘DynaGrow 2520 B2RF,’ and ‘Stoneville 5242 BR.’ Other cultivars were tolerant but less productive, including ‘Deltapine 488 BG/RR,’ ‘Fibermax 960 B2R,’ and ‘Stoneville 5599 BR.’ ‘Deltapine 455 BG/RR,’ ‘Phytogen 370,’ and ‘Phytogen 485’ were shown to be productive, but not tolerant to the reniform nematode.

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