Semi-field evaluations of arthropod repellents: emphasis on spatial repellents

Authors: Kline, Daniel - Dan; MCKENZIE, K - Woodstream Corporation; Bowman, Adam

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 8/5/2021
Publication Date: 10/14/2021
Citation: Kline, D.L., Mckenzie, K., Bowman, A.R. 2021. Semi-field evaluations of arthropod repellents: emphasis on spatial repellents. In Corona, C., Debboun, M. Coats, J. editors. Advances in Arthropod Repellents. Elsevier Inc. p. 193-236. https://doi.org/10.1016/B978-0-323-85411-5.00007-8.
DOI: https://doi.org/10.1016/B978-0-323-85411-5.00007-8

Interpretive Summary: This chapter explains the difference between topical and spatial repellents. It describes the advantages and disadvatages of using each type and how they can best be utilized to manage biting arthropod populations with emphasis on mosquitoes. It also surveys the various types of semi-field enclosures used worldwide to evaluate the efficacy of these repellents.

Technical Abstract: This chapter describes the attributes of topical and spatial arthropod repellents (SRs) and the use of semifield environments to evaluate their efficacy parameters. Topical arthropod repellents are chemical compounds placed directly on the exposed skin and require either contact by the biting arthropods or very close proximity to stop them from biting at the very last stages of their feeding processes. In contrast, SRs are volatile compounds that become airborne and prevent/discourage blood-seeking arthropods from making physical contact or even entering a defined space occupied by a potential host, thus protecting it from bites. The SRs can reduce biting arthropod density and ultimately human-vector contact over a larger area as long as the active ingredient concentration in air is high enough to repel or kill the arthropod vectors. The focus of this chapter is on the use of semifield environment to conduct efficacy testing of commercially available arthropod repellent products and the development of novel ones. Semifield studies serve as a bridge between laboratory and field studies, and not a replacement for either. Not only are semifield environments useful for understanding the biology and behavior of biting arthropods but also for developing methods of control and disease mitigation. The structure and types of experiments that have been conducted in semifield environments found worldwide are briefly summarized. While the dimensions of these screened enclosures varied, they were sufficiently large to reflect an area that SRs are intended to protect under local ambient environmental conditions. SR studies conducted at the USDA Center for Medical, Agricultural and Veterinary Entomology, Gainesville, Florida, United States, past, current, and future are presented in more detail.