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United States Department of Agriculture

Agricultural Research Service

Title: PRAIRIE GRASSES AS HOSTS OF THE WESTERN CORN ROOTWORM (COLEOPTERA: CHRYSOMELIDAE)

Authors
item Oyediran, Isaac - UNIVERSITY OF MISSOURI
item Hibbard, Bruce
item Clark, Thomas - UNIVERSITY OF MISSOURI

Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 12, 2004
Publication Date: June 1, 2004
Citation: Oyediran, I.O., Hibbard, B.E., Clark, T.L. 2004. Prairie grasses as hosts of the western corn rootworm (coleoptera: chrysomelidae). Environmental Entomology. 33(3):740-747.

Interpretive Summary: The registration of transgenic corn with resistance to corn rootworm larval feeding offers a viable alternative to insecticides for managing the most economically important insect pests of corn. Maintaining susceptibility to transgenic crops (resistance management) is in the interest of growers, the Environmental Protection Agency, and industry, but requires an understanding of corn rootworm biology (such as larval use of alternate hosts) that does not currently exist. We evaluated 21 prairie grass species thought to be among those dominant 200 years ago in the western Great Plains as larval hosts of the western corn rootworm. Corn and sorghum were included as positive and negative controls. The percentage of larvae recovered from western wheat grass, pubescent wheat grass, and side-oats grama were not significantly different than those adults produced from corn. Overall, adults were produced from 14 of the 23 species evaluated. The number of adults produced by pubescent wheatgrass was not significantly different than the number produced from corn. The average dry weight and head capsule width of adult corn rootworms produced from western wheatgrass, pubescent wheatgrass, slender wheatgrass, and galleta were not significantly different than the head capsule widths and dry weights of adults produced from corn. This information will be important to seed companies, the Environmental Protection Agency, and modelers in their attempts to develop resistance management plans for transgenic corn.

Technical Abstract: We evaluated 21 prairie grass species thought to be among those dominant 200 years ago in the western Great Plains as larval hosts of the western corn rootworm, Diabrotica virgifera virgifera LeConte. Corn (Zea mays L.) and sorghum (Sorghum bicolor L.) were included as positive and negative controls. Twenty-five pots of each plant species were planted and the five pots within each of five replications were randomly assigned a sample date for larval extraction. Five weeks after planting, pots were infested with 20 neonate western corn rootworm larvae using a moistened camel's hair paintbrush. At 5, 10, 15, and 20 d after infestation, pot contents were placed in Tullgren funnels equipped with 40 W lights for larvae extraction. The remaining five pots were used for adult emergence data. The percentage of larvae recovered, larval and adult average dry weights, larval and adult head capsule width, and adult emergence varied significantly between the species. The percentages of larvae recovered from western wheat grass (Agropyron smithii Rydb.), pubescent wheat grass (Agropyron trichophorum Link.), and side-oats grama (Boutelua curtipendula Michx. Torr.) were not significantly different than corn when sample dates were combined. The number of adults produced by pubescent wheatgrass was not significantly different than the number produced from corn. Average dry weight and head capsule width of adults produced from western wheatgrass, pubescent wheatgrass, slender wheatgrass (Elymus trachycaulus (Link) Gould) and galleta (Pleuraphis jamesii Torr.) were not significantly different than the head capsule widths and dry weights of those adults produced from corn. Overall, adults were produced from 14 of the 23 species evaluated. The results from this study are discussed in relation to the potential ancestral hosts of western corn rootworm larvae, and to resistance management of transgenic maize.

Last Modified: 10/31/2014
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