Mechanisation of pre-flowering leaf removal under the temperate climate conditions of Switzerland

The present trial follows a previous study about pre-flowering leaf removal (LR) (Verdenal et al., 2019) and validates the sustainability of mechanical LR under local Swiss vineyard conditions, using low-pressure double airflow, to reduce cost laborious bunch thinning. In studies, has shown additional benefits over post-berry-set in terms yield regulation grape wine compositions. This had two objectives: 1) test technical feasibility LR, airflow 2) observe impact this practice five years on parameters, composition at harvest quality years. For purpose, was conducted cultivars, Doral (white) Gamay (red), compare four treatments, that is, A) B) manual C) D) + LR. More broadly, work provides practical insights into consequences grapevine, pointing out advantages limits intensity, timing mechanisation practice. comparison with induced 7 % loss bud fruitfulness, 30 3 gain total soluble solids (TSS) accumulation grapes both although improvement maturity small uneven through years; anthocyanin concentration remained stable. Pre-flowering no overall wines. Damage observed inflorescences due intensity which resulted fewer berries per cluster lower than by same date. A second after berry set also tested limit growth laterals clean clusters from remaining flower caps prevent development fungal diseases, but it did not show any benefit single conclusion trial, single, moderate is an effective sustainable temperate climatic costs