Agricultural Economics Department


First Advisor

Cory Walters

Date of this Version

Spring 5-5-2023


Bethlem, I. B. 2023. "Economic Analysis of Western Corn Rootworm Injury to Continuous Corn in Northeast Nebraska." Thesis, Department of Agricultural Economics, University of Nebraska-Lincoln.


A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Agricultural Economics, Under the Supervision of Professor Cory Walters. Lincoln, Nebraska: May 2023

Copyright © 2023 Isadora Vercesi Bethlem


The most economically significant corn pest in the US Corn Belt is the Western Corn Rootworm (WCR), Diabrotica virgifera virgifera LeConte. This study compares a field experiment outcome of 4 different treatments against WCR, which consist of a rootworm Bt corn pyramid (SmartStax®) and non-rootworm Bt trait hybrid (VT2P), with or without the addition of the rootworm soil insecticide (Aztec®) to identify the risk-reward trade-off for each one of them. Observed prices were used for the years in the study (2020, 2021, and 2022), and low and high price scenarios were simulated for the period, to incorporate different dynamic relations between years. Also, different WCR Bt resistance levels and rootworm densities were accounted for: fields were classified into four groups based on susceptibility (corrected survival ³ 0.5 and < 0.5) and population pressure (root injury for the control treatment ³ 1 and < 1). This study also addresses how crop insurance plays a role in offsetting revenue to farmers from the fields most affected by WCR, at two insurance coverage levels: 70% coverage level – a commonly used level - and 85% coverage level - as a specific strategy with moral hazard implications. We identified that SmartStax® was the most profitable option although adding the insecticide reduces production risk exposure. Also, crop insurance gives an advantage to non-rootworm Bt traits and the 85% coverage level for fields that presented low resistance but high population pressure.

Advisor: Cory Walters