A Localised and Sustainable Mussel‐Shell Strategy to Control a Scarab Pest in Vineyards

ABSTRACT In New Zealand, vines can suffer from severe damage produced by adults of the endemic scarab Costelytra giveni (Coleoptera: Melolonthinae). Information about the distribution of these insects within the crop can provide valuable insights for adapted sustainable pest control strategies. Here, adult distribution of this pest has been assessed by counting adults that landed on vine plants in two vineyards in New Zealand. Distribution patterns within vineyard blocks were evaluated over three consecutive years using generalised linear mixed‐effects models. Our results suggest that adult beetles were concentrated at the edge of the vineyard, with a density that decreases towards the centre. In addition, the application of crushed mussel shells as mulching under the vines at different distances from the edge reduced adult numbers at the local scale, that is, with no effect on the next non‐treated bay. Our results suggest that treating at least the first 15 m from the edge towards the centre of the vineyard leads to a significant reduction in adult numbers, which can be enough to maintain low levels of infestation and alleviate the main damages caused by adult C. giveni . Based on these results, protocols can be developed for non‐pesticidal or restricted pesticide management of this pest, as well as for other species displaying similar crop colonisation patterns or behaviours in different agroecosystems worldwide.