2007 Annual Report 1a.Objectives (from AD-416) Define the impact of Arundo donax, carrizo cane in Rio Grande Basin (RGB) using remote sensing and ecohydrology. Investigate the genetic relatedness of RGB A. donax with populations from its native range in Europe. Evaluate biological control agents from Europe for control of A. donax in RGB. Obtain approval for release of agent(s) in N. America based on studies in quarantine containment facilities. Pilot test augmentative release of agent(s) on Rio Grande River in Texas. Evaluate impact of agents on A. donax stands. 1b.Approach (from AD-416) Remote sensing will be used to define the density of A. donax in the RGB and to estimate the total area infested. Ecohydrologial studies will be used to determine the water use of A. donax and predict the water gain if stands can be reduced using biological control agents. Molecular genetics will be used (microsatellites) to determine the origin (river system) in Europe of RGB A. donax. Insect biological control agents adapted to the invasive RGB clonal type will be collected from this location and shipped to USDA quarantine facilities in TX for host range specificity testing. Based on the results these tests and subsequent approval for release in N. America, a mass rearing program will be developed to release large numbers of the biological control agents at a test location along the Rio Grande River near Laredo, TX. Field evaluation will be conducted to determine the impact of the biological control agents on A. donax and non-target species such as Phragmites australis, common river cane. 3.Progress Report This report serves to document research conducted under a Reimbursable Agreement between ARS and the Dept. of Homeland Security, Science and Technology Division. This research is integrated with objectives in the parent CRIS 6204-22000-019-00D, Biologically Based Management of Field and Greenhouse Crops. Arundo donax L., carrizo cane, giant reed is an exotic and invasive weed of riparian habitats and irrigation canals of the Rio Grande River Basin and the southwestern U.S. Carrizo cane dominates these habitats, which leads to loss of biodiversity; catastrophic stream bank erosion; damage to bridges; and increased costs for chemical and mechanical control along transportation corridors. Additionally, this invasive weed competes for water resources in an arid region where these resources are critical to the environment, agriculture, and municipal users. Biological control using insects from the native range of carrizo cane may be the best option for long-term management of this weed. Arundo donax is a good target for biological control because it has no close relatives in North or South America, and several of the plant's feeding insects from its native range in Mediterranean Europe are known to be specialists feeding only on this one plant species. Carrizo cane is a major impediment to Department of Homeland Security, Customs and Border Protection (DHS-CBP) operations and law enforcement activities on the international border between Laredo and Del Rio. An interagency agreement is in place with DHS to accelerate the existing ARS A. donax biological control program. This multi-faceted program is required to produce the type of information and data needed for approval of a biological control agent by Biological Control of Weeds Technical Advisory Group (Mexico, U.S., and Canada) and USDA-APHIS. The goal of this research program is to evaluate, select and gain approval for biological control agent(s) of carrizo cane and conduct a pilot release program on the Rio Grande River near Laredo. Should this method prove to be effective in the pilot test, a larger mass-rearing and mass application program will be initiated. To determine the distribution and density of A. donax in the Rio Grande Basin (RGB), remote sensing using both satellite and aerial images has been initiated. Images from several parts of the RGB have been obtained and are being analyzed. Genetic sampling of A. donax in the RGB and Europe has revealed that one dominant clone occurs north of Laredo. This genotype matches most closely with populations of A. donax near Valencia and Huelva, Spain. Candidate agents have been collected from these ‘origin’ locations and will be prioritized in the testing. Host range testing of the Arundo wasp, Tetramesa romana, is nearly complete, and testing of the Arundo scale, Rhizaspidiotus donacis, has been initiated. Development of these candidate agents has only been observed on the target weed, Arundo donax. The ADODR is in regular contact with the cooperator through phone and email.