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United States Department of Agriculture

Agricultural Research Service

Research Project: BIOLOGICALLY BASED CEREAL APHID MANAGMENT Title: Distribution and diversity of Russian wheat aphid (Hemiptera: Aphididae) biotypes in North America

Authors
item Puterka, Gary
item Burd, John
item Porter, David
item Shufran, Kevin
item Baker, Cheryl
item Bowling, Bob - TEXAS A&M, DUMAS, TX
item Patrick, Carl - TEXAS A&M, LUBBOCK, TX

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 1, 2007
Publication Date: October 1, 2007
Repository URL: http://handle.nal.usda.gov/10113/9276
Citation: Puterka, G.J., Burd, J.D., Porter, D.R., Shufran, K.A., Baker, C.A., Bowling, B., Patrick, C. 2007. Distribution and diversity of Russian wheat aphid (Hemiptera: Aphididae) biotypes in North America. Journal of Economic Entomology. 100(5):1679-1684.

Interpretive Summary: The Russian wheat aphid (RWA) was introduced into the United States in 1986. Within two years after its introduction, it spread throughout the western half of the country and became a very destructive pest of wheat and barley. In 1996, wheat bred with natural resistance was deployed and was the primary means of managing this pest. In 2002, a new race of RWA appeared that was able to overcome resistance in wheat. Five new races, referred to as biotypes, have recently been identified in the USA but the extent of frequency and distribution was not know. This study collected 365 samples from 7 states where the RWA is primarily distributed and were characterized by biotype using resistant and susceptible plant reactions. The biotypic diversity across all sites was 27.2% RWA1 and 72.8% RWA2. RWA biotype distribution by state indicated that RWA2 was the predominate biotype and composed 73 - 95% of the biotype complex in Texas, Oklahoma, Colorado, and Wyoming. RWA2 dominates the biotype complex in its primary range in the United States. Our study indicates that RWA2 has rapidly dominated the biotype complex in wheat and barley within its primary range from Texas to Wyoming. Wheat with RWA resistance based on Dn4, will have little value in managing RWA in the United States, based on the predominance of RWA2.

Technical Abstract: Russian wheat aphid (RWA) samples were collected from 73 sites in Oklahoma, Texas, New Mexico, Colorado, Kansas, Nebraska, and Wyoming in 2005. Collection sites were 8-40 km apart in distance depended continuity of the wheat and barley fields. We collected 3-5 infested tillers/site, depending on infestation level. All but 10 of the sites had 2-8 samples, with the majority of sites having at least three samples taken. A total of 365 clones were established from these sites and biotype analysis. The biotypic status of each clone was determined in two phases of resistance screening to four wheat entries. In the first phase, the response of RWA resistance genes Dn4, Dn7, and susceptible 'Custer' was determined in a screening pot test. Three weeks after infestation, plant damage ratings indicated the presence of only two biotypes, RWA1 and RWA2. The second phase of screening that was designed to differentiate biotypes RWA4 from RWA5 verified that only RWA1 and RWA2 were collected in this study. Biotype diversity across all sites was 27.2% RWA1 and 72.8% RWA2. RWA biotype distribution by state indicated that RWA2 was the predominate biotype and composed 73 - 95% of the biotype complex in Texas, Oklahoma, Colorado, and Wyoming. RWA2 dominates the biotype complex in its primary range in the United States. Our study indicates that RWA2 has rapidly dominated the biotype complex in wheat and barley within its primary range from Texas to Wyoming. Wheat with RWA resistance based on Dn4, will have little value in managing RWA in the United States, based on the predominance of RWA2.

Last Modified: 10/25/2014
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