Document Type

Thesis - Open Access

Award Date

1984

Degree Name

Master of Science (MS)

Department / School

Plant Science

Abstract

The genus Echinacea, family Asteraceae, contains several species of herbaceous, warm season perennials possessing varying amounts of biologically active materials. Echinacea is indigenous to the central or west-central U.S. and ranges from Texas and Alabama to Saskatchewan in Canada. McGregor recognizes 9 species and 2 varieties of Echinacea; the taxa of western distribution occurring in dry areas of prairie and grassland ecotype, those of more eastern distribution in dry, rocky, open woodlands, hillsides, or glades. All taxa are considered to be drought-tolerant, disease and pest-resistant plants of agriculturally marginal land. Morphological variation within this genus has led to much debate concerning the treatment of taxa. Chromosomal variation of taxa also limits classification, e.g. Echinacea pallida Nutt. is a segmental allopolyploid and E. angustifolia D.C. var. strigosa McGregor has both diploid and tetraploid populations. While all taxa are self-sterile, laboratory F1 hybrids have been produced from all possible species combinations, although percentage of success varied with the combination. Frequent hybrids are found in nature with greater success coming from the more morphologically dissimilar and geographically separated taxa. Extracts from the roots of Echinacea have yielded several biologically active compounds, including an insecticide, antibiotic, anticancer agent and antiviral substance. Previous research methods utilized the root as the source of plant material for analysis, and in the process, destroyed the plant. Since E. pallida is a perennial, removal of the above ground parts after the growing season would allow growth the following season from the remaining rootstock. The objective of this research was to perform insect bioassays and preliminary chemical analysis on the components extracted from the achenes of E. pallida. Included in the analysis were fatty acids, carbohydrates, the protein content, and insecticidal amides. The latter was the focus for research and evaluated as a contact insecticide by topical application to adult and larval stages of the western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte. Bioassays were also conducted to determine if a substance, structurally similar to the botanical insecticide, could be synthesized in the laboratory that would mimic the physiological activity of the natural insecticide.

Library of Congress Subject Headings

Biological assay
Chemistry, Analytic
Insecticides -- Analysis

Format

application/pdf

Number of Pages

87

Publisher

South Dakota State University

Rights

No Copyright - United State
http://rightsstatements.org/vocab/NoC-US/1.0/

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