Submitted to: Journal of Stored Products Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/5/2006
Publication Date: 4/30/2007
Citation: Vardeman, E.A., Campbell, J.F., Arthur, F.H., Nechols, J.R. 2007. Behavior of Rhyzopertha dominica (Coleoptera: Bostrichidae) in a mono-layer of wheat treated with diatomaceous earth. Journal of Stored Products Research 43: 297-301. Interpretive Summary: Diatomaceous earth (DE) can be used to control insects in stored wheat, but we don't know if DE affects movement of insect pests. We treated wheat with different formulations of DE, put the treated wheat in a single layer between two glass panes, and observed the behavior of the beetles. Patterns of movement were the same in all of the DE-treated wheat and in untreated wheat. Results show that DE did not affect beetle behavior, and differences in mortality between specific DE products are more likely due to characteristics of the individual formulations rather than to differences in behavior caused by the different DE formulations.
Technical Abstract: Adult female lesser grain borers (Rhyzopertha dominica [F.]) were observed in a mono-layer of wheat sandwiched between two layers of glass to determine if movement patterns and survival rates differed in wheat that was admixed with diatomaceous earth (DE) compared with untreated wheat. Observations were also made to determine if responses to DE differed depending on the commercial formulation of DE tested at the labeled rates. Movement patterns were not significantly different among treatments; however, mortality was higher in the DE treatments than in the untreated controls, and also varied according to the DE formulation. In wheat treated with 1,000 ppm Dryacide®, 400 ppm Protect-It®, and 500 ppm InsectoTM (labeled rate for the individual products), mean percentage mortality was 100 ± 0, 71.4 ± 10.1, and 57.1 ± 11.1, respectively. Because DE did not have an appreciable effect on movement patterns of R. dominica, observed differences in mortality are likely related to DE products or amount applied rather than to differences in DE exposure resulting from movement behavior.