Effective distances of wasp (Vespula vulgaris) poisoning using clustered bait stations in beech forest

Abstract

Poison baiting from fixed bait stations is currently the most effective method to reduce the ecological impacts of invasive Vespula vulgaris wasps in New Zealand. Maintaining extensive bait lines or grids and later removal of unused baits within forest habitats is, however, difficult and time-consuming. To improve costeffectiveness and to make use of wasps' ability to forage at long distances from the nest, we tested the efficacy of using clusters of bait stations. We set up three clusters around Lake Rotoiti within Nelson Lakes National Park, each containing eight stations baited with Xtinguish TM (active ingredient 0.1% fipronil) for 3-4 days in early February, 2010 and recorded the traffic rates of 144 V. vulgaris nests, at varying distances from bait clusters, before and after treatment. The distance from a bait station cluster significantly affected the change in traffic rates, with a GLM model predicting an 80% reduction in average colony size within 113 m of a cluster, and a 50% reduction within 250 m but no reduction at 470 m. The efficacy of the poison baiting was affected by initial colony size-large colonies had greater reductions in traffic than small colonies. Nests up to 150 m higher in elevation than the clusters were as likely to be destroyed as those at the same elevation as the clusters. While overall this baiting strategy did not produce the 80-90% average traffic reductions achieved by more intensive grid baiting systems, it suggests that spacing grouped bait stations approximately 250 m apart has the potential to reduce wasp densities to below an ecologically damaging level with considerably less effort.

Efficacy of Protein Baits with Fipronil to Control Vespa velutina nigrithorax (Lepeletier, 1836) in Apiaries

“…However, bait consumption depended on the number of hornets present in the apiary with optimal results when more than 30 hornets were present at the same time in front of the hives. The reduction in the number of hornets in the group of apiaries with >30 hornets (≈75%) was similar to other studies that used protein baits with fipronil to control Vespula species in natural environments [ 39 , 47 , 58 ], but lower in comparison to others [ 38 , 41 ]. However, the concentration of fipronil used in the present study is ten times lower (0.01% w / w ) than the concentrations of fipronil used to control other species of Vespidae (0.1% w / w ) [ 59 ].…”

“…The best strategy is to combine different methods throughout the annual activity period of the hornets. In this study, we present another method successfully used with other members of the Vespidae family [ 38 , 40 , 41 , 47 ] based on chemical control with toxic baiting. Several biocides have been investigated to control wasps, and fipronil provided optimal efficacy at low doses [ 53 , 54 ].…”

“…Several authors found that increasing the intensity of baitings increases their efficacy [ 38 , 47 , 58 ]. As seen in this study, the use of biocides such as fipronil can be useful to control V. velutina populations in the periods of highest pressure in the apiaries.…”

“…Most of the protein baits commercialized for the control of the Vespidae family contain fipronil as the biocide in their composition [ 41 , 42 , 46 , 47 ]. Fipronil is a systemic insecticide of the phenyl pyrazole family that acts by blocking neuronal inhibitory receptors, leading to neuronal hyperexcitability produced by the accumulation of the neurotransmitter GABA in the synaptic cleft, generating the death of the individual [ 48 ].…”