Thesis (Ph. D.)--Leland Stanford junior university, 1907. / Cover title. eContent provider-neutral record in process. Description based on print version record.

Thesis (Ph. D.)--Leland Stanford junior university, 1907. / Cover title. Also issued in print.

Thesis (M.S. in botany)--Washington State University, August 2010. / Title from PDF title page (viewed on July 22, 2010). "School of Biological Sciences." Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1980. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

No description available.

Thesis (Ph. D.)--University of Tasmania, 1999. / Includes bibliographical references.

Four closely related species of leaf beetles (Diorhabda spp.; Coleoptera:Chrysomelidae) have been introduced into the western United States as biocontrol agents for the invasive Eurasian shrub tamarisk (Tamarix spp.; Violales:Tamaricaceae). These beetles have since continued to spread and establish throughout the western United States. Another exotic insect, the tamarisk leafhopper (Opsius stactogalus, Fieber;Hemiptera: Cicadellidae), had previously become established in these areas and now shares tamarisk as a host plant with the beetles. To assess more carefully the potential for interactions between leafhoppers and beetles, field censuses and cage studies were conducted to determine the phenologies and potential interactions of O. stactogolus and D. carinulata when attacking Tamarix ramosissima (Ledebour) in western Colorado. The leafhopper underwent development through at least three generations per season, whereas the beetle was shown to develop through two generations per season. Variation in leafhopper abundance was associated with the extent and type of foliar damage to tamarisk trees. Individual trees with greatest D. carinulata abundances and subsequent defoliation had significantly reduced O. stactogalus abundances thereafter. Abundance of O. stactogalus was also shown to vary significantly among tamarisk plants in cage settings where leafhoppers were given the choice of potted tamarisk plants with ~50% damage to foliage from D. carinulata versus undamaged plants. In contrast, D. carinulata abundance was not shown to differ strongly in response to O. stactogalus damage in the field or in cage experiments. Field results across sites, however, showed similar trends of reduced beetle abundance on plants more heavily attacked by leafhoppers, and larval growth tests suggested slight reductions in larval pupation and adult emergence of D. carinulata when grown on O. stactogalus-damaged tamarisk. It is not clear if slight tendencies in D. carinulata abundance along with much stronger responses in O. stactogalus abundance were the result of limited plant material, rather than an induced plant defense. It is clear, however, that these specialist herbivores are interacting in an asymmetric competitive fashion while feeding on the same host plant.

No description available.

Thesis (Ph. D.)--Mississippi State University. Department of Entomology and Plant Pathology. / Title from title screen. Includes bibliographical references.

Bean leaf beetle, Cerotoma trifurcata (Forster) (Coleoptera: Chrysomelidae), is an economic pest of soybean in Ontario. Field cage studies were conducted in 2010-2011 to determine voltinism in southern Ontario and the effect of C. trifurcata feeding during soybean reproductive stages on soybean yield and quality. Thermal requirements for C. trifurcata development were determined in a laboratory study. Results of field and laboratory studies support the occurrence of one generation of C. trifurcata in southern Ontario. Pod-feeding increased with both number of beetles and soybean reproductive stage. An increase in defoliation and a reduction in seed quality were observed with increasing number of beetles. Monitoring programs for late-season pod-feeding should begin when degree days approach 500 (base 9.31°C). Economic thresholds for C. trifurcata during soybean reproductive stages range from 0.27 to 2.00 beetles per plant or 8 to 60 beetles per m of row. / Ontario Ministry of Agriculture and Food – University of Guelph Sustainable Production (Plants) Program and Grain Farmers of Ontario through the Farm Innovation Program.