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United States Department of Agriculture

Agricultural Research Service


Location: Crop Protection and Management Research

Title: Changes in the weed species composition of the southern US: 1995 to 2009

item Webster, Theodore
item Nichols, R.l.

Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 1/18/2011
Publication Date: 2/1/2011
Citation: Webster, T.M., Nichols, R. 2011. Changes in the weed species composition of the southern US: 1995 to 2009. Weed Science Society of America Meeting Abstracts. #71.

Interpretive Summary:

Technical Abstract: Changes in the weed flora of crops reflect not only the influx and losses to the soil seedbank, but also the management impacts. This analysis documents the changes in the weed flora of the 14 contiguous states comprising the Southern Weed Science Society since the advent of transgenic, herbicide resistant crops, and relates these changes to management factors using the available data. In soybean, morningglories, nutsedges, and sicklepod were among the top five weed species in 1995 and 2009. Palmer amaranth and horseweed were the second and fourth most troublesome weeds of soybean. Horseweed, Florida pusley, Benghal dayflower, and groundcherries had the largest increases in troublesomeness. In cotton, morningglories and nutsedges were among the top five most troublesome weeds in 1995 and 2009. Palmer amaranth, pigweeds, and Florida pusley were also listed among the five most troublesome species in 2009. The weeds with the largest increase in importance were Benghal dayflower, Florida pusley, and common ragweed. In corn, the top five weeds were morningglories, Texas millet, broadleaf signalgrass, johnsongrass, and sicklepod. These same weeds were the top five in 1994, but johnsongrass was the most troublesome. The species with the greatest increase in corn were Palmer amaranth, smartweeds, and goosegrass. In wheat, the top four weeds in 2008 were the same as in 1994 and include Italian ryegrass, wild garlic, wild radish, and henbit. The number five weed and species that increased most in importance was annual bluegrass.

Last Modified: 06/24/2017
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