The objective of this proposed project is to identify and devise formulations of natural products, particularly the eremophilane sesquiterpene nootkatone, and evaluate their repellency to and effectiveness for the reduction of questing nymphal Ixodes scapularis in the field. We propose several candidate natural low-toxicity chemicals potentially toxic or repellent against I. scapularis. Working with a scientist with the USDA Agricultural Research Service, we will improve the current emulsifiable concentrate (EC) formulation of nootkatone and develop preliminary encapsulation techniques for this chemical using coacervation, Fantesk encapsulation, and spray dried encapsulation. Formulation samples will be screened in the laboratory at The Connecticut Agricultural Experiment Station for efficacy against I. scapularis and the formulations will be optimized for aqueous spray applications. Field trials will be conducted in communities in Fairfield and Litchfield Counties of Connecticut; areas with high tick densities and endemic for Lyme disease. The repellency of the new natural product candidates will be evaluated initially in the laboratory against I. scapularis. In the field, repellency of nootkatone, and other candidate natural products will be evaluated using treated and untreated flannel tick drags. In addition, we will bring several added components to the proposed project beyond the stated objectives in the funding opportunity announcement that will enhance the outputs and outcomes of the research. Chemical analysis of field samples will provide nootkatone residue-degradation data. In addition, we propose to further test the compatibility and field efficacy of the entomopathogenic fungus Metarhizium anisopliae Strain 52 with nootkatone and other natural products, which may permit effective use of lower concentrations of the natural compounds in the field for a more economical and integrated natural approach to tick control. ? ? ?