2007 Annual Report 1a.Objectives (from AD-416) The objective of this cooperative research project is an effort to develop, through laboratory research at FDWSRU and field testing in Greece, a Greek isolate of the smut fungus Microbotryum cardui as a biological control agent for weeds in the genus Carduus and closely related thistles (7 species) that were introduced to the U.S. These thistles and the smut fungus are indigenous to Greece. The goals are to:. 1)determine the efficacy of the fungus in infecting and damaging these thistles in the field in Greece and. 2)determine the host range among related non-target species. 1b.Approach (from AD-416) Teliospores of M. cardui, collected in Greece from 2002-2005, will be used at the EBCL substation at American Farm School in Thessaloniki, Greece, where a technician will be hired to inoculate Carduus and related plants, including Cirsium spp., Cynara scolymus, and Carthamus tinctorius. Successful reisolations of teliospores from inoculated plants will be sent to FDWSRU for ITS sequence analysis and comparison to the original isolates. At the same time as the infection and host range studies are being set up, a separate set of patches of Carduus and related thistles, that have been reported as hosts of M. cardui, will be located and inoculated with M. cardui. All plants within the patches will be inoculated. The patches will be monitored each successive spring for the presence of teliospore-producing capitula. At the conclusion of the project, the effect of M. cardui on the number and proportion of infected plants of each type (systemically and locally infected) and density of each species will be analyzed by comparing observed infected and non-infected plant dynamics to simulated dynamics. 3.Progress Report This report serves to document research conducted under a Specific Cooperative Agreement between ARS and the American Farm School (AFS) in Thessaloniki, Greece, 1920-22000-031-02S. Additional details of research can be found in the report for the parent project 1920-22000-031-00D, "Evaluation and Characterization of Exotic Plant Pathogens for Biological Control of Introduced, Invasive Weeds", Objective 1, Sub-objective 3. This agreement was established to place scientific expertise at this USDA-ARS European Biological Control Laboratory satellite location for collaborative research measuring the efficacy of promising fungal pathogen bio-control candidates on target invasive weeds in the field. During the course of the year, we continued, in replicated field tests, host-range testing of non-target plants with the smut fungus Microbotryum silybum Vanky & Berner and the smut fungus Microbotryum cardui that we discovered on Carduus pycnocephalus (Italian thistle), in May, 2005. The target species (Silybum marianum (milk thistle) and Carduus pycnocephalus were included in each test. In addition to research on host-range of the two smut fungi, another epidemiology test was set up in fields within American Farm School, in October, 2006. This test supplements tests that were set up in 2004 and 2005 in two nearby fields. In all tests, teliospores of M. silybum were inoculated onto naturally occurring rosettes of Silybum marianum. The objective of the tests is to monitor the spread of diseased S. marianum plants in these fields over time. Results of our initial inoculations (2004 and 2005) of these fields were that the fungus did not establish in the fields inoculated in 2004 and 2005. However, plants diseased with the fungus were abundant as a result of our 2006 inoculations. We are now conducting soil tests on soils from areas where the smut has been successfully established for years and comparing these test results to results from soils where the fungus has failed to establish. In 2005, an isolate of Colletotrichum gloeosporioides was found on Salsola tragus in Greece. An isolate of this fungus from Hungary has been extensively researched at FDWSRU and is a promising candidate for biological control of Salsola tragus. The discovery of the fungus in Greece has allowed us to conduct field tests with this indigenous pathogen. In the fall of 2006, a replicated epidemiology test was established outside of Serres, Greece to determine spatial and temporal spread of the disease caused by the fungus in relation to rainfall and temperature. Results from this test indicated that about 30% of the S. tragus plants became diseased and that the disease progressed about 10 meters from each focal point. These results occurred under very dry conditions in Serres, and the upper limit of disease was ultimately restricted by frost. This project was monitored by an extensive site visit, in 2007, as well as, numerous calls and e-mails to the cooperator over throughout the year.