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Document Type

Thesis - University Access Only

Award Date


Degree Name

Master of Science (MS)



First Advisor

Michael B. Hildreth


The purpose of this masters thesis was to compare the virulence and pathogenicity of N. locustae in two grasshopper species (M. sanguinipes and M. bivittatus) that naturally differed in their sensitivity and susceptibility to this pathogen. In order to accomplish this task, bioassay studies and histopathological studies at the light microscopic and ultrastructural level were conducted using these two grasshopper species. It is hoped that by understanding why N. locustae is more virulent and pathogenic in one grasshopper species and less virulent and pathogenic in another, we may then be able to better understand how this microsporidian damages its hosts. Understanding the normal mechanism for pathogenicity may eventually enable us to improve the virulency of N. locustae and thereby enhance its effectiveness in the field.

Library of Congress Subject Headings

Locusts -- Biological control
Biological assay
Histology, Pathological



Number of Pages



South Dakota State University