Common Home Remedies Do Not Deter Argentine Ants, Linepithema humile (Hymenoptera: Formicidae), from a Preferred Harborage.

Simple Summary: The Argentine ant, Linepithema humile (Mayr), was introduced into the United States from South America in the late 1800s. Since its establishment in California and the southeastern U.S., it has become an agricultural pest by interfering with citrus production in California, but it is widely known in most of its range as a major nuisance pest. It commonly establishes nest sites in mulch and leaf litter, where colonies may be populated by hundreds of thousands of worker ants (or more) with a large home range. When searching for food, ants may discover and recruit to sweet foods inside of structures. To alleviate ant pest problems, the structural pest control industry may incorporate EPA-approved baits and residual products that are designed to reduce the ant population. Homeowners experiencing nuisance pests are often motivated to solve their own problem, and they may be susceptible to outlandish, fact-free claims of do-it-yourself "secret" solutions that "they don't want you to know about". In this study, we evaluated several of these recommendations. In two trials designed to evaluate a product's ability to deter Argentine ants from a preferred nest site, we evaluated several common home remedies, namely the use of tansy plant leaves, cucumber peels, and soybean extract. None of these home remedies deterred ants from a preferred harborage. Fresh leaves from rosemary and spearmint plants, however, did deter ants, as do many commercially available essential oils. In two laboratory trials, natural products, including freshly picked leaves from spearmint, rosemary, and tansy plants, a water extract from soybean plants, peels from a common cucumber, and 1% peppermint oil in hexane, were placed in a moist harborage preferred by Argentine ants, Linepithema humile (Mayr), and the number of ants entering the harborage after two and four hours was counted. None of the recommended home remedies (tansy, cucumber, or soybean extract) deterred ants from an attractive, moist harborage in either trial, even when the quantity of these treatments was increased 4- to 10-fold. Freshly picked leaves from rosemary and spearmint plants deterred ants from harboring, and the 1% peppermint oil was the most deterrent of all treatments. [ABSTRACT FROM AUTHOR]