Submitted to: Applied Entomology and Zoology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/2/2018
Publication Date: 6/1/2018
Citation: Machtinger, E.T., Yang, X., Chen, J., Li, A.Y. 2018. Repellency and toxicity of five ant defensive compounds against the lone star tick, Amblyomma americanum (Acari: Ixodidae). Applied Entomology and Zoology. https://doi.org/10.1007/s13355-018-0559-7.
Interpretive Summary: Lone star ticks are important pests that can transfer pathogens that can cause disease in humans and animals. These ticks are common, aggressive, and expanding in distribution over the United States. There are public concerns over the safety of common repellents like DEET, so it is necessary to investigate more naturally derived compounds as potential repellents against lone star ticks. USDA-ARS scientists conducted a study to evaluate repellency of several natural compounds against ticks. Two of the test materials, decylamine and MT-710, were found to be as repellent as DEET, but were not as toxic. The results suggest these naturally derived compounds may offer alternatives to DEET and other traditional repellents.
Technical Abstract: + The lone star tick, Amblyomma americanum, is a vector of several important human and animal diseases. This tick species has rapidly expanded in its geographic distribution, and its aggressive behavior has increased the risk of tick-borne diseases in these new areas. Repellents are recommended by the Centers for Disease Control and Prevention (CDC) for protection against tick bites. DEET is the most common repellent, but public concerns over safety have increased the need for alternative safe and efficacious tick repellents. Several naturally derived animal compounds have been tested against other species of ticks or other arthropod pests, but not against A. americanum. Based on EC50 values obtained using a vertical paper bioassay, decylamine and MT-710 (a 2-tridecanone formulation) were found to be as repellent as DEET, and those two substances along with 2-tridecanone were as effective as DEET at EC95. Lone star ticks were more susceptible to the toxic effects of DEET in glass vial assays than all ant defensive compounds/formulations. The results suggest that these ant defensive compounds are likely more effective as repellents, but do not have the toxic effects as DEET on lone star ticks. Suitability of these compounds for use as personal repellents, as well as on a landscape scale should be explored.