2007 Annual Report 1a.Objectives (from AD-416) Conduct pre-release evaluation of A. petiolata and native plant species in Michigan. Evaluate potential impact of herbivore feeding on population regulation of A. petiolata. 1b.Approach (from AD-416) To predict the potential for successful biological control of A. petiolata combines empirical and modeling studies of A. petiolata demography. The empirical studies will determine the expected range of values for A. petiolata demographic rates in a variety of habitats and locations in Michigan. The modeling studies will include matrix simulation analyses of transient dynamics and asymptotic growth rate of A. petiolata populations subjected to mortality by biological control agents under varying environmental conditions. These analyses will help assess whether biological control of A. petiolata is feasible under a wide range of growing conditions. 3.Progress Report This report serves to document research conducted under a Reimbursable Agreement between ARS and Michigan State University. Additional details of research can be found in the report for the parent project 3611-22000-018-00D, Biologically and Ecologically Based Knowledge for Integrated Weed Management Systems. Research was conducted to characterize variation in the population dynamics of garlic mustard, an invasive plant of woodland habitats of North America, as a means of guiding biocontrol agent releases for control of this species when the agents come out of quarantine in several years. Two field locations were established in Illinois to complement locations already established in Michigan. Data on garlic mustard population densities, seedling germination, plant survival and seed production were collected and incorporated into a database for Illinois and Michigan. Coordination between participants was achieved through meetings and site visits. The demographic data are being analyzed to reveal situations where single or multiple agents will be effective. The importance of this study lies in its power to guide successful biocontrol of garlic mustard while helping to avoid unecessary introductions of multiple biocontrol agents whenever possible. Such an approach will help reduce the risk of unintended effects of biocontrol agents on nontarget organisms.