Document Type

Dissertation - Open Access

Award Date


Degree Name

Doctor of Philosophy (PhD)

Department / School


First Advisor

Edward U. Balsbaugh, Jr.


A laboratory colony of Altica carduorum Guer. was established from a stock colony of 50 adult beetles. They had an average previposition period of 7 days when exposed to a regular cycle of 16 hr. of light (24° C) and 8 hr. of darkness (12.75° C). Under these conditions, females laid an average of 259.3 ± 9.7 eggs, and longevity averaged 100 days. The eggs are laid on the underside of leaves along edges of leaf veins throughout June. Adults fed and overwintered in the soil, and some beetles emerged the following spring and laid viable eggs. Laboratory studies indicate that high temperatures and/or low RH are limiting factors to beetle survival. Preliminary findings suggest that the beetle may be reared on southern corn rootworm artificial diet which wither contains or does not contain Canada thistle extract. Results of field studies suggest that this beetle can be colonized in South Dakota. One of the major factors limiting the establishment of field colonies are the predators, Lebia viridis and Harpalus pennsylvanicus. A. carduorum originates from central and south Europe which has a Mediterranean type climate where rainfall is heavy, and the humidity is high. Therefore, establishment of A. carduorum in South Dakota, where the summers are usually hot and dry, will be most difficult. Suspected mycoplasma-like bodies were found in sieve elements of Canada thistle plants displaying symptoms of yellows disease.

Library of Congress Subject Headings

Canada thistle
Weeds -- Control -- Biological control
Beetles -- South Dakota




South Dakota State University

Included in

Entomology Commons