2007 Annual Report 1a.Objectives (from AD-416) To improve the scientific basis for management of yellow starthistle. Elements are to. 1)develop rehabilitation strategies for early, mid and late seral plant communities,. 2)monitor and evaluate the impact of biological control agents on yellow starthistle in Idaho,. 3)determine habitat susceptibility and dispersal patterns of yellow starthistle,. 4)develop integrated pest management (IPM) decision tools for effective management of yellow starthistle,. 5)train agency scientists and land managers in appropriate integrated management of yellow starthistle infested habitats. 1b.Approach (from AD-416) Develop integrated vegetation management strategies, using the tools of biological control, seeding desirable plant species, herbicides, grazing management and controlled burns to rehabilitate infested plant communties. Monitor and evaluate the impact of biological control agents on yellow starthistle in Idaho. Predict where yellow starthistle is likely to infest by determing habitat susceptibility and dispersal patterns of the weed. Develop integrated pest management (IPM) decision tools for effective management of yellow starthistle on various types of habitats. train agency scientists and land managers in appropriate integrated management of yellow starthistle infested habitats through field days, demonstrations, publications and multi-media presentations. Documents SCA with University of Idaho. 3.Progress Report This report serves to document research conducted under a Specific Cooperative Agreement between ARS and the University of Idaho. Additional details of research can be found in the report for the parent CRIS 5325-22000-020-00D Biology and Management of Invasive Weeds in the Western United States. A two-year field study using insect exclosure was conducted in Hell’s Canyon, Idaho to evaluate the efficacy of introduced seed-feeding insects released in the mid 1990s for the control of yellow starthistle. Despite larval attack rates of up to 94% of available capitula, approximately 9 seeds per attacked capitula escaped larval herbivory. A combination of adult and larval feeding resulted in a total maximum seed reduction of 71%. At this rate of seed reduction, seed-feeding insects presently established in Hell’s Canyon are not sufficient to control yellow starthistle populations. Progress was monitored by the ADODR periodically by phone and email, and by meeting with the cooperators in April.