Conservation Biological Control of Western Bean Cutworm: Molecular Gut Content Analysis of Arthropod Predators, Feeding Trials for Key Predators and Agricultural Surveys for Integrated Pest Management

Authors

Westen Ray Archibald, University of Nebraska-LincolnFollow

First Advisor

Julie A. Peterson

Second Advisor

Robert J. Wright

Date of this Version

8-2017

Document Type

Thesis

Citation

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: Entomology

Under the supervision of Professors Julie A. Peterson and Robert J. Wright

Lincoln, Nebraska, August 2017

Includes an appended erratum added February 17, 2025

Comments

Copyright (c) 2017, Westen Ray Archibald. Used by permission

Abstract

Western bean cutworm (WBC), Striacosta albicosta, is a major pest of corn in western Nebraska. In 1999, its range expanded into much of North America causing damage from Nebraska to Canada and Mexico. WBC periodically causes kernel damage as severe as 15 bu/ac for one larva/plant. Control for WBC relies on Bt corn hybrids with Vip3A and Cry1F traits and insecticides. There has been a 5.2-fold decrease in efficacy of Cry1F for WBC. Concerns over management tactics may be creating space for conservation biological control to become part of a WBC integrated pest management (IPM) program. Objective 1, used an online survey to determine Nebraska stakeholder concerns, understanding, and practices for WBC IPM. Respondents self-reported significantly higher yield loss due to WBC in 2016 than in 2015 and 2014. Growers demonstrated low knowledge of WBC identification and management. There were frequent reports (58.45%) of Cry1F Bt corn providing decreased control against WBC. In objective 2, predator surveys for natural enemies of WBC indicated that four generalist predators were ubiquitous in Nebraska corn fields. Some species had population dynamics that were associated with the WBC population dynamics in corn. Lab-based feeding trials indicated that Coleomegilla maculata (De Geer) was a superior predator for WBC eggs and larvae. However, molecular gut content analysis of surveyed predators found in-field predation by multiple generalist predators but not C. maculata. By determining the needs of growers and the role of predators for WBC, conservation biological control may be incorporated into a WBC IPM program.

Advisors: Julie A. Peterson and Robert J. Wright