2007 Annual Report 1a.Objectives (from AD-416) The objectives of this cooperative research is to determine distribution and density of A. donax in the mid and lower Rio Grande Basin. 1b.Approach (from AD-416) Sites in the Rio Grande Basin will be visited by Pronatura staff to determine the density and distribution of A. donax. GPS coordinates will be taken above and below dams along the riparian zones which will be used to obtain Quickbird images. Arundo donax shows up in this images as a distinctive pink color which can the be translated on computer to hectares infested. The number of hectares infested can then be used to estimate the number of river miles infested with A. donax in the Rio Grande Basin. 3.Progress Report This report serves to document research conducted under a Specific Cooperative Agreement between ARS and Pronatura Norestre (Mexico). This research is integrated with objectives in the parent CRIS 6204-22000-019-00D, Biologically Based Management of Field and Greenhouse Crops. Invasive exotic plant species and other noxious weeds pose a huge and increasing threat to agriculture and native ecosystems throughout North America. In our region, which includes the Rio Grande River Basin (RGB), invasive weeds degrade the riparian environment and consume water resources in an arid region impacted by recurrent drought. Arundo donax L. is one of the most serious and widespread invasive weeds in the watershed, and a biological control program is needed because available chemical and mechanical control methods are not applicable over such a large area. The introduction of natural enemies from the origin of the A. donax (Mediterranean Europe) could be an effective solution, but these agents must be rigorously evaluated for both safety and efficacy. This project was initiated in FY 2007 to determine the distribution of A. donax in the RGB. Ground surveys have been conducted in Tamaulipas, Coahuila, and Chihuahua, Mexico, to determine the location and severity of A. donax infestations along the major tributary rivers of the RGB. The Rio Sabinas, Salado, Conchos, San Juan have been surveyed. Collections of plant material for genetic analysis, GPS coordinates, and digital photographs and been taken of more than 60 sites. Arundo donax plants were found to be widespread along these rivers in the RGB; however, the densities of the infestations were light to moderate, except along the irrigation canals and drainage ditches. Surveys are on-going in the RGB to ground truth data gathered from remote sensing images. This research supports remote sensing activities being conducted by the Integrated Farming and Natural Resources Research Unit, Weslaco, TX. The ADODR is in regular contact with cooperator via e-mail and phone contacts.