2012 Annual Report
1a.Objectives (from AD-416):
Predict chemical structures which will lead to the discovery of novel insecticides and repellents of mosquitoes and biting flies.
1b.Approach (from AD-416):
Compounds with known insecticidal and repellent properties will be selected for modeling from the USDA database of over 30,000 tested chemicals. The subsets of chemicals will be modeled by sophisticated modern computer systems to develop quantitative structure-activity/property relationships (qsar/qspr) to define and improve mosquito and fly insecticides and repellents. Candidate insecticides and repellents will be obtained commercially, or synthesized as needed. Chemicals will be bioassayed for insecticidal and/or repellent properties.
This project is conducted in support of Objective 1, “Discover and evaluate new toxicants and biological control agents for control of biting Nematocera,” and Objective 3, “Conceive and test new methods of managing vector and pest populations through the use of behavior-altering chemicals, including repellents, attractants, and inhibitors.”
Research efforts by the Organic Chemistry group and the Mosquito and Fly Research Unit (MFRU) in Gainesville, FL, consisted of bioassays of novel compounds as mosquito repellents, larvicides, and adulticides. Compounds selected from a 1977 report on testing against Yellow Fever mosquitoes were selected and bioassayed for minimum effective dosage (to produce repellency) against Ae.aegypti mosquitoes. The efficacy data was used to generate an extremely accurate model of the structure and electronic properties of these models that lead to the observed repellent efficacy level. The quantitative structure activity relationship (3D-QSAR) methodology that is used by our University of Florida collaborators analyzes chemicals for repellent activity based on their structure and various other structurally-related chemical properties. In the past year, we completed testing of 20 compounds of which 1 showed comparable activity to N,N-diethyl-3-methylbenzamide (DEET) (the gold standard of repellents), 3 had relatively high repellent activity, and 5 had moderate repellent activity.