Submitted to: Pesticide Biochemistry and Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/9/2011
Publication Date: 3/17/2011
Publication URL: http://hdl.handle.net/10113/49432
Citation: Sial, A.A., Brunner, J.F., Garczynski, S.F. 2011. Biochemical characterization of chlorantraniliprole and spinetoram resistance in laboratory-selected obliquebanded leafroller, Choristoneura rosaceana (Harris)(Lepidoptera:Tortricidae). Journal of Pesticide Biochemistry and Physiology. 99:274-279. Interpretive Summary: Oblique-banded leafroller is an apple fruit pest controlled at times with pesticide sprays. Scientists at the USDA-ARS Yakima Agricultural Research Laboratory in Wapato, WA in collaboration with scientists at Washington State University characterized insecticide resistance mechanisms used by oblique-banded leafrollers and other tree fruit pests. They found that detoxification enzymes are present in the leafroller that may provide the insect some resistance to chemical insecticides in use in apple orchards. The new information indicates that the leafroller has potential to develop resistance to these new pesticides, instructs pest managers that programs must be in place to minimize resistance development, and provides researchers with a method to monitor changes in leafroller resistance over time.
Technical Abstract: Neonate larvae of obliquebanded leafroller, Choristoneura rosaceana, from a laboratory colony were exposed to two reduced-risk insecticides, chlorantraniliprole and spinetoram. After nine generations of selection, significant levels of resistance to each insecticide were observed. Biochemical assays were performed on third instar larvae to determine potential resistance mechanisms. Enzyme assays indicated that esterase activity was significantly increased in chlorantraniliprole-selected colony, whereas mixed-function oxidase levels were elevated in spinetoram-selected colony as compared to the unselected colony. No difference in glutathione-S-transferase activity was seen in either of the insecticide-selected colonies. These results indicate the potential involvement of esterases and mixed-function oxidases as detoxification mechanisms responsible for resistance to chlorantraniliprole and spinetoram, respectively. Furthermore, the results of this study suggest that chlorantraniliprole and spinetoram are not detoxified by similar mechanisms and could therefore be incorporated into resistance management programs in tree fruit leading to sustainable management of C. rosaceana.