Evidence of Field-Evolved Resistance to Bifenthrin in Western Corn Rootworm (Diabrotica virgifera virgifera LeConte) Populations in Western Nebraska and Kansas

Abstract

Pyrethroid insecticides have been used to control larvae or adults of the western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, a key pest of field 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. Concentration-response bioassays were performed to estimate the baseline susceptibility. From the baseline data, a diagnostic concentration (LC99) was determined and used to test adults of both laboratory and field populations. Larval susceptibility was also tested using 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 2 and Chase Counties, NE, with LC50s of 2.2 and 1.38 μg/vial, respectively, and Finney County 1, 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.

Cross-resistance and synergism bioassays suggest multiple mechanisms of pyrethroid resistance in western corn rootworm populations

“…Bifenthrin data from 2014 collections is published in Pereira et al [10] and is presented in Fig 2 to facilitate comparison of susceptibility with the other two insecticides. Two susceptible field populations, from Saunders (2014 and 2015) and Scotts Bluff Counties (2015), were also tested.…”

“…Adult populations from eight sites in southeastern Keith County (Fig 1) were bioassayed at LC 99 to evaluate potential spatial variability in susceptibility to bifenthrin among populations given the low susceptibility of Keith 1–3 to bifenthrin found in 2013 and 2014 [10]. …”

Response of Cry3Bb1‐resistant western corn rootworm (Coleoptera: Chrysomelidae) to Bt maize and soil insecticide

“…Currently, pyrethroids such as bifenthrin are commonly used to manage rootworm larva and adults. However, western corn rootworm adults have now developed resistance to pyrethroids in some parts of the United States (Pereira et al., ).…”

Comparative CYP‐omic analysis between the DDT‐susceptible and ‐resistant Drosophila melanogaster strains 91‐C and 91‐R

“…The subsequent loss of effective control has led to challenges in controlling these insects with regard to the production of agriculturally important crop plants as well as the protection of human health. For example, recurrent exposure of the Western corn rootworm, Diabrotica virgifera virgifera , to carbamate, organophosphate, and organochlorine insecticides in agricultural fields imposed a selective pressure that led to the evolution of resistant populations . Analogously, insecticide resistance within insect populations that are vectors of disease pose public health risks to humans .…”