Area-wide management of the invasive garden ant Lasius neglectus (Hymenoptera: Formicidae) in northeast Spain

Abstract

The invasive ant Lasius neglectus (Hymenoptera: Formicidae) has become an urban pest in northeast Spain and continental Europe and is currently expanding its range and threatens to become as serious a pest as the Argentine ant. One invading population occupying 14 ha and located in northeast Spain has been managed with a large-scale insecticide treatment, with the aim of reducing its damaging effects in houses and on human well-being. During the spring and summer periods of 2001–2002, 45 households were treated. Some non-urbanized, seminatural infested areas were also treated to avoid the pest expansion. The treatment plan was intended to attack three key aspects of the ants as well as directly killing the ants: (a) killing/destroying ant food sources, (b) limiting access to the ant’s food sources, and (c) impeding access to the interior of houses. The pest control treatment involved a combination of canopy fogging, tree trunk spraying, a house perimeter injection treatment, and in-house baiting. Reduction of ant trails on trees was 73% (2001) and 68% (2002). Spots with ants at the perimeter of the house were reduced by 47% (2001) and 30% (2002). Both the objective assessment of the treatments and the positive opinion of the inhabitants of the houses confirmed the efficacy of the treatment program.