Formulating Farnesol and Other Ant-Repellent Semiochemicals for Exclusion of Argentine Ants (Hymenoptera: Formicidae) from Citrus Trees

Abstract

Lemon trees banded with experimental formulations of farnesol and other natural ant repellents were examined for efficacy of disruption of the foraging of the Argentine ant, Linepithema humile (Mayr), at varying periods of time after application. Excellent disruption of foraging was achieved by the use of a band constructed from a single strand of cotton twine permeated with 40 mg each of farnesol and Stickem per centimeter of twine. An “ant tape,” consisting of twine similarly permeated with farnesol and Stickem and covered with a strip of waxed paper, was under some conditions superior in duration of disruption of ant foraging to the noncovered, treated twine. Efforts to produce an effective barrier from farnesol mixed with Stickem and beeswax and formulated into a paste, which was then applied around tree trunks, have not been successful. The better formulations of farnesol tested have given between 2 and 3 mo of complete ant exclusion from banded trees. Other tested repellent compounds have not been as active or provided as long a duration of effectiveness as farnesol.