Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Plant Science

First Advisor

James L Krysan


This thesis concerns the biology of Diabrotica cristata a small relatively inconspicuous beetle inhabiting relict prairie and grass lands in the Great Plains Region of North America. Diabrotica cristata has been classified taxonomically in the virgifera group and is, therefore, closely related to several very important pest species including Diabrotica virgifera virgifera LeConte, the western corn rootworm (WCR), Diabrotica virgifera Krysan and Smith, the Mexican corn rootworm (MCR) and Diabrotica barberi Smith and Lawrence, the northern corn rootworm (NCR). The genus Diabrotica (Chrysomelidae) is composed of three groups: fucata, virgifera and signifera. The virgifera group not only includes the above pests as well· as D. cristata, but also Diabrotica longicornis a species whose range overlaps Q. barberi in the Central Plains (Nebraska south to Texas and Mexico). The larvae of all of the Diabrotica species are root feeders while the adults feed on pollen, silks and the floral parts of plants. The WCR and the NCR are major pests of corn in the Midwest, whereas D. cristata and D. longicornis have not been identified as corn pests. Q. cristata occupies relict prairies of the United States, northern Mexico east of the Rocky Mountains and Canada. Perennial grasses are characteristic features of relict prairies, and the larvae are believed to feed on the roots of native perennial grasses. Chittenden reported that a Mr. Pratt in 1899 observed D. cristata attacking the blossoms of lima beans at Travilah, Maryland, while Kirk and Balsbaugh reported the collection of adults of Q. cristata from Cirsium sp. thistle (composite); Amorpha canescens, lead plant (leguminosae); Rhus coriaria, smooth sumac (Anacardiaceae); Psoralea sp, scurfpea (leguminasae) as well as from the ends of ears of corn. Douglas (1929) also reported the collection of D. cristata from corn. Many adult Diabrotica species such as D. longicornis and the WCR feed on and are closely associated with cucurbits, however, adult NCR's tend not to associate with cucurbits. D. cristata is only occasionally collected from cucurbits even though the NCR and D. crista ta have similar behaviors, with both species observed feeding on the flowers of a variety of prairie forbs. Unlike the NCR, D. longicornis and Q. cristata, the adult WCR has not been observed feeding on the flowers of prairie forbs. In the laboratory. Q cristata will feed and develop as larvae when fed upon corn roots. This fragment of information suggest that the NCR and Q. cristata may share similar host plants under natural conditions in the field. Such studies with Q cristata may reveal underlying bases for the association of these species with plants and hence provide clues to features which confer pest status on species of the virgifera group. Such information could be useful in the development of pest management methods to suppress populations of an insect that could evolve into a future pest of grasses.

Library of Congress Subject Headings

Beetles -- Host plants -- South Dakota



Number of Pages



South Dakota State University


No Copyright - United State