An innovative sprayer design: Methodology for optimal plant protection of bed-grown carrots

The H2020 OPTIMA Project aims at developing an integrated solution for plant protection including the early detection of fungal diseases, the definition of new bioproducts, the development of an IPM (integrated Pest Management). A collaborative methodology was initiated in order to design a spraying solution adapted to open field bed-grown carrots and to prevent them from a fungi disease named Alternaria. Laboratory measurements were achieved at ILVO Institute (Belgium) for droplet size & droplet velocity measurements, lateral spray distribution and at the University of Torino (Italy) for airflow intensity characterization. Compared to a broadcast application, optimal nozzle spacing and height were defined in order to maximize quantitative deposition based on the lowest coefficient of variation on the target area and the lowest losses outside the deposition zone for various crop development stages. Semifield conditions were used at INRAE Montpellier to practically evaluate the different spray configurations in terms of deposition on carrot plants, ground losses as well as the potential spray drift. Carrots of two different varieties were cultivated in bins representing two beds. This methodology allowed the definition of several optimal spray configurations based on the optimal selection of nozzles and the adaption of nozzle settings in terms of nozzle spacing and nozzle height to bed spray application.