|PEREIRA, ADRIANO - University Of Nebraska|
|WANG, HAICHUAN - University Of Nebraska|
|ZUKOFF, SARAH - Kansas State University|
|MEINKE, LANCE - University Of Nebraska|
|SIEGFRIED, BLAIR - University Of Nebraska|
Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/23/2015
Publication Date: 11/13/2015
Citation: Pereira, A.E., Wang, H., Zukoff, S.N., Meinke, L.J., French, B.W., Siegfried, B.D. 2015. Evidence of field-evolved resistance to bifenthrin in western corn rootworm (Diabrotica virgifera virgifera LeConte) populations in western Nebraska and Kansas. PLoS One. 10(11): e0142299. doi:10.1371/journal.
Interpretive Summary: The western corn rootworm (WCR) is a resilient pest of corn in the United States. In response to reports of reduced efficacy of bifenthrin (a pyrethroid insecticide) in WCR management programs in southwestern areas of Nebraska and Kansas we determined a lethal concentration (LC99) to test larvae and adults of both laboratory and field populations. Our results showed that resistance of WCR field populations to bifenthrin is emerging and evolving in southwestern regions of both Nebraska and Kansas, which historically has used bifenthrin for larval control during planting, as well as for adult control to reduce oviposition of females. Our study provides a better understanding of the nature of bifenthrin resistance and its potential to spread to other corn growing regions, and the basis for additional studies of cross-resistance and inheritance of insecticides which ultimately will lead to sustainable WCR management.
Technical Abstract: Pyrethroid insecticides are widely used to control larvae or adult western corn rootworm, a key pest of corn in the United States. In response to reports of reduced efficacy of pyrethroids in WCR management programs in southwestern areas of Nebraska and Kansas the present research was designed to establish a baseline of susceptibility to the pyrethroid insecticide, bifenthrin, using susceptible laboratory populations and to compare this baseline with susceptibility of field populations. WCR adults and neonates were exposed to 6-8 increasing insecticide concentrations plus control to estimate the baseline susceptibility. From the baseline data, a diagnostic concentration (LC99) was determined and used to test larvae and adults of both laboratory and field populations. Significant differences were recorded in adult and larval susceptibility among WCR field and laboratory populations. The highest LC50 for WCR adults was observed in populations from Keith and Chase Counties, NE, with LC50’s of 2.2 and 1.38 µg/vial, respectively, and Finney County, KS, with 1.43 µg/vial, as compared to a laboratory non-diapause population (0.24 µg/vial). For larvae, significant differences between WCR field and laboratory populations were also recorded. Significant differences in mortalities at the diagnostic bifenthrin concentration (LC99) were observed among WCR adult populations with western Corn Belt populations exhibiting lower susceptibility to bifenthrin, especially in southwestern Nebraska and southwestern Kansas. This study provides evidence that resistance to bifenthrin is evolving in field populations that have been exposed for multiple years to pyrethroid insecticides. Implications to sustainable rootworm management are discussed.