2006 Annual Report 4d.Progress report. This report documents research conducted under a Reimbursable Agreement between ARS and The Bureau of Land Management. Additional details of the research can be found in the report for the parent project 5325-22000-020-00D, Biology and Management of Invasive Weeds in the Western US and in a previous reimbursable agreement (5325-22000-017-12R) that this project replaced. Biological control of several invasive weeds of the western United States has been proposed as one of the only cost effective methods to management species like saltcedar, broom and yellow starthistle and thus this project was continued with the Bureau of Land Management to expand the potential of this technology for key target species important to both agencies. The USDA-ARS Exotic and Invasive Weeds Research Unit of Albany, CA, in cooperation with the Biological Control of Weed Project at Temple, TX, and the European Biological Control Laboratory in Montpellier, France, have identified, colonized and are now testing new natural enemies of these target weeds. Beetles from China worked well in some areas of the country but in California and Texas these agents did not establish, spread or significantly impact the target saltcedar. A new leaf beetle, Diorhabda elongata, that attacks saltcedar has been imported from Greece, and is thought to be better suited to saltcedar control in more southern areas of the United States and thus required additional testing prior to actual field release. This testing work was completed in FY2006 and formal release petitions submitted to USDA-APHIS in the spring. The agents released to now seem to be effective causing defoliation of the target weeds across the release areas but have not yet spread to significant levels nor caused extensive defoliation as has occurred in other locations beyond Texas. It is hoped that this beetle will soon respond to the local conditions and cause similar damage as seen in the northern areas of the United States. If successful, this project should provide cost effective long term control in these new locations.