2005 Annual Report 4d.Progress report. This report serves to document research conducted under a Specific Cooperative Agreement between Louisiana State University and ARS. Additional details of the research can be found in the report for the parent research project 0500-00044-013-00D, Area-Wide Pest Management of the Tarnished Plant Bug in Cotton in Absence of the Boll Weevil. The research was conducted on commercial farms near Newellton, LA. Two areas, a treated and a non-treated area were established. In the treated area, marginal areas near roads, fields, and ditches were treated with a herbicide in March to kill broadleaf host plants of the tarnished plant bug. Both areas had over 1000 acres of cotton in them. Weed hosts in marginal areas were sample for plant bugs prior to and after treatment. Cotton grown in the areas was sampled weekly for plant bugs weekly during June and July. The early season herbicide treatment caused a significant reduction in numbers of plant bugs found in marginal areas of the treated area as compared to the check area. Tarnished plant bug adult densities were lower in cotton in the treated area as compared to the non-treated area for three weeks during late June to early July in 2004. Densities of nymphs were lower in cotton in the treated area for about five weeks from late June to late July. These results indicated that the herbicide treatment was effective in reducing plant bug infestations in cotton. Samples of runoff water taken in March after the herbicide application, were analyzed for the presence of 2,4-D and Dicamba, both of which are found in the herbicide used in the treated area. No residues were found. The analyses were performed by ANALAB, Corporate Laboratory, Kilgore, TX, using EPA method 8151 for the analyses.