Entomology, Department of


Document Type


Date of this Version

December 2003


Published in Journal of Economic Entomology Volume 96, Issue 6 (December 2003) pp. 1855–1863. This article is the copyright property of the Entomological Society of America and may not be used for any commercial or other private purpose without specific written permission of the Entomological Society of America. Used by permission.


A consistent correlation between elevated esterase activity and methyl parathion resistance among Nebraska western corn rootworm, Diabrotica virgifera virgifera LeConte, populations has previously been documented. Characterization of general esterase activity using naphtholic esters as model substrates indicated that differences between resistant and susceptible strains could be maximized by optimizing assay conditions. The optimal conditions identified here were similar to those reported for other insect species. The majority of general esterase activity was found in the cytosolic fractions of resistant populations, whereas the activity was more evenly distributed between cytosolic and mitochondrial/nuclear fractions in the susceptible population. General esterase activity was predominately located in the adult thorax and abdomen. Although there were significant differences in general esterase activities between resistant and susceptible populations, the differences exhibited in single beetle activity assays did not provide sufficient discrimination to identify resistant individuals. In contrast, single larva activity assays provided greater discrimination and could be considered as an alternative to traditional bioassay techniques.

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