Project Number: 3620-22410-010-07
Project Type: Trust

Start Date: Apr 01, 2008
End Date: Mar 31, 2009

Objective:
1) Identify all-natural (i.e., non-synthetic, produced by nature), low-toxicity chemicals extracted from botanical sources that are toxic to the nymphal stage of the blacklegged tick, Ixodes scapularis, including the eremophilane sesquiterpene, nootkatone; 2) Formulate these natural products into water soluble or emulsified compounds, determine the optimal concentrations that kill nymphal I. scapularis, and devise formulations, including microencapsulated active ingredients or other slow release formulations, that persist in killing nymphal ticks for a longer duration than the active ingredient itself; 3) Field test formulations against populations of the blacklegged tick in areas endemic for Lyme disease and determine the percent control achieved; 4) Determine whether control of ticks using test chemicals is accomplished by direct toxicity to ticks, and test for spatial repellency effect of the chemical applied to vegetation; and 5) Test for repellency effect of natural products on I. scapularis nymphal ticks in a field setting.

Approach:
Development of effective formulations for the application of the hydrophobic agent (nookatone), as described in this research proposal, are suitable for other hydrophobic agents including entomopathogenic fungal spores, insect pheromones and plant volatile compounds as identified in the parent project, and specifically under Objective 2. Formulation of Microbial Biocontrol Agents and Semiochemicals ¿ Milestones: 2C1 (Spray Drying of Hydrophobic Agents); and 2D3 (Formulations of Volatile Compounds). ARS will contribute to the proposed research project to develop biorational tick control as part of a grant proposal submitted to the CDC by Dr. Kirby Stafford, Connecticut Agricultural Experiment Station. Successful development of tick control strategies have direct implications for reducing the incidence of tick born human disease. The ARS portion, provided by Dr. Robert Behle, of the proposed research will focus on developing formulations for application of nookatone, an eremophilane sesquiterpene from grapefruit known to be toxic to ticks. Formulation techniques developed for this grant will be directly applicable to developing formulations for the application of other hydrophobic agents identified under our stated project objectives and milestones above. For example, eremophilene is a plant volatile being researched for control of the invasive emerald ash borer. Dr. Behle¿s portion of this proposed research (objective 2 - to develop and provide formulated samples for testing) may include but are not limited to developing effective emulsifiable concentrates, and encapsulating active agents using spray-drying, coacervation, or the Fantesk process for oil encapsulation. Formulations will address critical issues of application and residual activity, as each issue limiting effective pest control is identified by the grant research team.