Research Accomplishment Reports 2010

Ecology and Management of European Corn Borer and Other Lepidopteran Pests of Corn

J. White
Department of Entomology

 

Non-Technical Summary

The planting of transgenic corn in the United States has increased dramatically since the mid-1990s. However, the widespread planting of Bt-corn throughout the United States means that many non-target arthropods are exposed to endotoxin proteins which were initially designed to restrict pest populations. Feeding on the abundant components of the detrital food chain could increase the likelihood of uptake of Bt-endotoxins by predator communities. We propose to quantify, for the first time, the interaction pathways between transgenic insecticidal crops expressing Cry1Ab and Cry3Bb1-endotoxins and the non-target arthropod food web.

Using antibody-based quantitative technology (which has already been developed and optimized) for the detection of these proteins in invertebrates, we will test the hypothesis that transgenic endotoxins flow through the arthropod food chain. These interaction pathways are predicted to include significant flow through the detrital food web to carabids (by consumption of molluscs and annelids) and Araneae (through the consumption of Collembola). These species are major food resources for generalist predators in corn agroecosystems.

2010 Project Description

In 2010, we began collaborating with Dr. Bill Hutchison, University of Minnesota, on his area-wide survey of European corn borer. We set up a light trap location in Lexington, Kentucky, from which we collected European corn borer moths on a daily basis. These moths were shipped to the Hutchison group for mating status determination. In return, we received moths from 16 locations across the North central region, and are screening them for the presence of the microsporidian pathogen Nosema (via phase-contrast microscopy) and the bacterium Wolbachia (via diagnostic PCR). The data we collect is sent to Dr. Hutchison, to be incorporated into publications and presentations for the ongoing project, and is also disseminated to the NC205 group during the annual group meeting.

This research direction is nascent, and is associated with a new PI (White). It is ongoing and will continue with the new NC205 project. Previous Kentucky PIs on this project (Obrycki, Harwood) focused on potential non-target effects of Bt corn on other arthropods that interact with lepidopterous pests. They published seven scientific papers on the topic, and produced numerous scientific presentations.

2010 Impact

We have completed Nosema screening on a subset of 10 European corn borer moths per location, and found that Nosema remained present at all sites (despite reduced moth abundance at some sites) but that prevalence of the microsporidian varied widely from location to location, ranging from 10 to 80% infection.

We have not found evidence of Wolbachia or any other bacteria capable of manipulating corn borer reproduction. We are in the process of developing a molecular screen for Nosema, and plan to screen subsequent years of moths using both molecular and microscopic methodology. These results will contribute to an overall understanding of European corn borer population dynamics following area-wide suppression due to widespread adoption of Bt technology, and will complement previously collected information on the non-target effects of Bt technology.