Optimization of integrated pest management for powdery mildew (Unincula necator) control in a vineyard based on a combination of phenological, meteorological and aerobiological data

SUMMARY Powdery mildew is one of the most important vineyard diseases. Infection requires the interaction of a susceptible host (a vine in a phenological phase susceptible to the pathogen), a virulent pathogen (the fungus Uncinula necator (Schw.) Burr) and an environment favourable for disease development (optimal meteorological conditions). The aim of the present study was the implementation of a system to predict powdery mildew infection periods in order to optimize and reduce the application of pesticide treatments in a vineyard. The study was conducted in a vineyard of the ‘Ribeiro’ Designation of Origin region located in north-western Spain from 2006 to 2011, during the Vitis vegetative period. The phenological study was conducted following the BBCH phenological scale and infection risk index (IRI) was calculated based on the maximum temperature. Aerobiological sampling was performed using a LANZONI VPPS-2000 volumetric trap. The results of the study show that the critical phenological stages for powdery mildew infection are 5 (inflorescence emergence), 6 (flowering) and 7 (development of fruit), as consequence of the high susceptibility of the vine. The IRI allows determination of the periods in which the meteorological conditions could facilitate fungal attacks during the aforementioned phenological phases. Finally, the aerobiological model helps to identify and predict the times of real infection risk among the possible periods described by the IRI with high accuracy, in order to avoid possible reappearance of infection symptoms in the vine. The combination of these three variables provides a valuable tool to establish an accurate, modern, integrated pest-management strategy in a vineyard.