Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Evaluation of four plant extract repellents for management of the European red ant Myrmica rubra (Hymenoptera: Formicidae).

Abstract

Spearmint oil, peppermint oil, neem oil, and d-limonene were tested as nest site repellents against the colonization of the invasive European red ant, Myrmica rubra (L.) in both laboratory and field trials. In a laboratory assay, a 10% (v/v) solution of each extract repelled M. rubra colonies from nesting in plant pots filled with moist soil compared to water-treated controls, when applied as a dip to pots. Extracts also repelled colonies compared to a water control in a second laboratory experiment, where pots were dipped 15 d prior to the start of the experiment. In a 2008 field comparison, 20 plant pots, filled with moist potting soil, were dipped in either 10% (v/v) spearmint oil or peppermint oil, 70% (v/v) neem oil, or a water control and left in infested sites. Seven control pots were colonized over 3 mo, while none of the extract-treated pots were colonized. This field trial was repeated for a 15-wk duration in 2009 with the addition of a 10% (v/v) d-limonene solution as a treatment, and a change in neem oil concentration to 10% (v/v). Spearmint and peppermint oils repelled M. rubra colonies for the duration of the experiment. Neem oil and d-limonene repelled colonies for 3 and 4 wk, respectively. These extracts, especially mint oils, show potential as low-hazard repellents against M. rubra in greenhouse and nursery settings, and could reduce the number of new infestations incurred by the transport of plant stock.