Skip to main content
Entomology 2020 Main banner
Icon Legend
This session is not in your schedule.
This session is in your schedule. Click again to remove it.
Presentation Icons
Plenary
Plenary
Livestream
Livestream
On-Demand
On-Demand
Student Competition
Student Competition
Video Chat
Video Chat
Panel Discussion
Panel Discussion
Mixer
Mixer
Poster Icons
Poster
Poster
Student Competition
Student Competition
ViewAttendees 7

PBT

Student Competition 10-Minute Paper

Grad 10-min: PBT, Insecticide Resistance, Toxicology

Within season efficacy of foliar insecticide applications targeting adult western corn rootworms and evaluation of potential density reduction the following year in Nebraska

On-Demand
Student Competition On-Demand
Transgenic corn hybrids expressing insecticidal proteins derived from Bacillus thuringiensis Berliner (Bt) toxins active against the western corn rootworm, (WCR), Diabrotica virgifera virgifera LeConte, have been widely adopted by farmers in the U.S.  A project has been initiated in northeast Nebraska to assess the value of applying integrated management tactics to mitigate potential changes in WCR susceptibility to Bt pyramids in fields with historical use of Cry34Ab1/Cry35Ab1 and/or Cry3 traits.  A component of the project evaluates the potential role of foliar insecticide applications to: 1) reduce adult WCR densities within-season and 2) contribute to WCR management the following season.  Within-season control is the focus of this talk. Adult whole plant counts were recorded during July-August 2019 and 2020 in commercial cornfields before/after application of commonly used foliar organophosphate and pyrethroid insecticides and in untreated control cornfields.  In both years, a large significant within-field decrease in WCR density occurred in sprayed fields post-application with no significant change in density over time observed in unsprayed fields.  This suggests that WCR is still susceptible to foliar insecticides in northeast NE in contrast to southwest NE where resistance to pyrethroids has been documented.  Next steps: 1) Complete lab vial bioassays with insecticide active ingredients to complement field results; 2) analyze data collected from rootworm Bt and non-Bt corn planted in sprayed fields the following season (2020 and 2021) to evaluate the potential impact of foliar insecticide applications on WCR density, root injury, and yield.  Results will help optimize WCR IRM and IPM strategies.