Entomology, Department of


Date of this Version

Spring 4-18-2012


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 Professor Gary L. Hein. Lincoln, Nebraska: May, 2012

Copyright (c) 2012 Anthony Justin McMechan


The wheat-mite-virus complex is an important production constraint to winter wheat production in the Great Plains, and consists of three viruses; wheat streak mosaic (WSMV), wheat mosaic (WMoV) and Triticum mosaic virus (TriMV). Synergistic interactions between these viruses have resulted in increased rates of replication and transmission of viruses, thus increasing the potential impact on wheat yields. The wheat curl mite (WCM), Aceria tosichella Keifer is the only known vector of the viruses within the wheat-mite-virus complex.

Currently, three colonies of WCM have been characterized by differential responses to mite resistant genes (biotypes) in wheat and differential transmission of WMoV. A study was designed to determine TriMV transmission for these various wheat curl mite colonies. For each source plant, individual mites were transferred to 10 separate test plants and virus transmission determined via ELISA. Results indicate that TriMV is only transmitted by one of the three wheat curl mite colonies using single mite transfers.

An additional study was conducted to determine the impact of TriMV on the biology of the WCM. TriMV infected and uninfected plants were infested with 10 mites from each colony with population counts being taken every seven days. Results indicated that TriMV had a negative impact on the reproductive potential of the WCM. The results demonstrate the importance of the mite source on virus epidemiology.

Management tactics to reduce the impact of the wheat-mite-virus complex have focused primarily on the control of volunteer wheat; however, these tactics are not always effective at reducing yield losses. A field study was conducted from 2007-2011 to determine the impact of the combination of resistant variety and planting date on wheat yields under high virus pressure. Results indicated that both management tactics had a significant impact on yield; however, the combination of tactics provided the greatest yield potential under high virus pressure.

Advisor: Gary L. Hein

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