Geostatistical approach for spatial distribution analysis of Lobesia botrana (Den. & Schiff): (Lepidoptera: Tortricidae) in Douro Demarcated Region (DDR)

Abstract: The European grapevine moth (EGVM), Lobesia botrana (Den. & Schiff.), is the most important vineyard pest in Douro Demarcated Region (DDR) (North of Portugal) where the pest typically develops three generations per year, of which the third is the most damaging one. The mating disruption (MD) technique, an environmental safe control method against this pest was first used in this region in 2000, being increasingly applied since then. However, within this steep slope viticulture region, some major constraints to the use of MD technique were previously identified. The DDR is characterised by a very fragmented landscape with the majority of the vineyards organized in small plots, often bounded by other crops such as olive groves and by unmanaged non-crop habitats. The climatic conditions in DDR allow a high biotic potential for EGMV development. The strong altitude range and rugged orography as well as large number of plots under MD treated are important issues to consider for the successful application of the technique, in order to ensure the homogeneous distribution of the pheromone cloud through the treated area. To overcome some of these constraints, since the end of 2017 a partnership was set up between ADVID, a winegrower organization, the University of Trás-os-Montes and Alto Douro (UTAD) and four wine companies (Real Companhia Velha, Sogevinus Fine Wines, S.A., Dona Matilde Vinhos Lda. e Quinta do Vallado Sociedade Agrícola Lda.) through the project “CSinDouro – Confusão sexual (CS) contra a traça-da-uva, Lobesia botrana (Den. & Schiff.) em viticultura de montanha: caso particular da Região Demarcada do Douro (RDD)”. A key objective of this project is to investigate L. botrana population spatio-temporal dynamics inside and outside vineyards plots, in order to evaluate the effect of the landscape elements on pest distribution and on the effectiveness of MD. To introduce improvements in the use of MD at the plot level, in DDR conditions, a characterization of spatio-temporal variability, on adult male catches in pheromone traps, was performed through Geostatistical methods (IDW – Inverse Distance Weighting and Kriging), as well as an estimation of EGVM damages, by plot and by farm, in the three pest generations. The achieved results will be used for improving pheromone dispenser location as a way to get a homogeneous distribution of the pheromone cloud, according to landscape characteristics.