Location: Wheat, Sorghum and Forage ResearchTitle: Enhanced metabolism and selection of pyrethroid-resistant western corn rootworms (diabrotica virgifera virgifera leconte)
|SOUZA, DARIANE - University Of Florida|
|JIMENEZ, ARNUBIO - Universidad De Caldas|
|MEINKE, LANCE - University Of Nebraska|
|MILLER, NICHOLAS - Illinois Institute Of Technology|
|SIEGFRIED, BLAIR - University Of Florida|
Submitted to: Pesticide Biochemistry and Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/20/2020
Publication Date: 3/1/2020
Citation: Souza, D., Jimenez, A.V., Sarath, G., Meinke, L.J., Miller, N.J., Siegfried, B.D. 2020. Enhanced metabolism and selection of pyrethroid-resistant western corn rootworms (diabrotica virgifera virgifera leconte). Pesticide Biochemistry and Physiology. 164:165-172. https://doi.org/10.1016/j.pestbp.2020.01.009.
Interpretive Summary: The Western corn rootworm (WCR) is a significant pest of corn and related crops in the USA. As with many pests, WCR is becoming increasingly resistant to applied pesticides. Pyrethroids are a class of pesticides often used to combat WCR and pyrethroid-resistant WCR colonies are increasingly found in farmer's fields. Most importantly, WCR colonies that are pyrethroid-resistant are also resistant to other pesticides. Here, some of the biochemical events underlying pyrethroid resistance in WCR were evaluated. Results suggested that (1) insecticide resistance can occur within ~7 generations of exposure and (2) resistance to pyrethroids appears to be linked to faster metabolism of the pesticide in resistant WCR as compared to non-resistant insects. These data potentially illustrate some mechanisms by which WCR can evolve pesticide resistance. Such data will be useful in developing strategies to control this important pest species in the US.
Technical Abstract: Western corn rootworm (WCR) pyrethroid resistance has been previously reported in the United States (US) western Corn Belt, and cross-resistance and synergism studies suggested that both target site insensitivity and enhanced metabolism may be conferring WCR resistance to pyrethroids. The present study aimed to investigate the potential mechanisms of WCR pyrethroid resistance and to estimate the heritability of the resistance trait. Biochemical assays using model substrates and spectrophotometry revealed 2-4-fold higher activity of P450s and esterases in pyrethroid-resistant WCR populations, whereas the biological activity of glutathione S-transferase was similar between populations tested. No mutation in the para-homologous voltage-gated sodium channel was detected in pyrethroid-resistant WCR individuals by sequencing PCR products containing the L1014, T929, and M918 positions that are commonly associated with target site mutations in other pyrethroid-resistant insects. A pilot estimation of pyrethroid resistance heritability obtained during laboratory selection of a WCR population suggested a major genetic component of the resistance trait and predicted a 10-fold increase in WCR bifenthrin resistance within ~7 generations of insecticide lethal exposure. Results support earlier indirect evidence that enhanced metabolism may be contributing to WCR resistance to pyrethroids and illustrates the potential of WCR pyrethroid resistance evolution.