Agronomy and Horticulture Department
Date of this Version
Fall 11-28-2012
Abstract
Goss’s bacterial wilt and blight (Goss’s wilt) is a serious and sometimes severe disease of corn. Goss’s wilt was first identified in Dawson County Nebraska in 1969. Today Goss’s wilt can be found in two countries including the U.S. and Canada, and twelve states including Nebraska, Iowa, North Dakota, South Dakota, Minnesota, Illinois, Indiana, Texas, Kansas, Colorado, Wisconsin and Wyoming. Goss’s wilt was observed in Nebraska throughout the 1970’s, and from the early 1980’s until recently developed only sporadically. Around 2006, a re-emergence of the disease was observed in western Nebraska, northeast Colorado, and southeast Wyoming. Since then, reports of the disease have been rapidly increasing north, south, and east, and has been reported across the entire Corn Belt. A survey was implemented to determine what agronomic and environmental factors may be contributing to this development and increased incidence in corn growing regions of the U.S. The survey showed that the Goss’s wilt rating assigned by seed companies, planting population density, planting date in 2011, crop rotation, and percent crop residue cover were all important factors to whether or not a field tested positive to Goss’s wilt. A second study was implemented to determine if the bacterial pathogen had genetic differences based on geographical origin. The study used amplified fragment length polymorphism (AFLP) and a box polymerase chain reaction (BOX-PCR) to separate isolates based on differences in DNA banding patterns. The study concluded that Cmn isolates were genetically similar across the entire sampling region, and isolates with similar banding patterns could be found in all states included in the survey. A third study was implemented to test if alternate hosts of the pathogen may be playing a role in the dissemination and survival of the pathogen. Results from the study indicate that three species of foxtail were alternate hosts to Cmn. These included yellow, giant, and bristly foxtail. These results will help producers better manage and potentially prevent Goss’s wilt in the future.
Advisors: Tamra Jackson-Ziems, Greg Kruger
Comments
A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of the Requirements For the Degree of Master of Science, Major: Agronomy, Under the Supervision of Professors Tamra Jackson-Ziems and Greg Kruger. Lincoln, NE: November 2012
Copyright (c) 2012 Craig Bruce Langemeier