Leaves of Chardonnay vine were collected each September or October from 2020 to 2024 (2020 = 0, 2021 = 1, 2022 = 2, 2023 = 3, 2024 = 4, in the Year column), around the grape harvest period, on the Comité Champagne experimental site in Plumecoq, France. The sampling was carried out in five regions within Plumecoq domain: Garennes = 0, Genetic = 1, la Meule = 2 (in a neighboring plot belonging to a champagne producer), les Bases = 3, Luzerne = 4, and Terroir = 5, in the Zone column.
Five classes of vine leaves are considered: Leafroll = 0, Esca = 1, Jaundice = 2 (both Flavescence dorée and Blackwood), Healthy = 3, and Discoloration = 4 (manganese deficiency, chlorosis, magnesia deficiency, punctate, and bubaline) in the Class column. Vine classification were performed by experts from Comité Champagne through a prospecting process. Prospection consisted of walking through the vineyard plots to identify these five classes and to mark the plants with different labels. For each vine, we typically collected 16 leaves, with a few exceptions due to insufficient leaf availability. The leaves were selected from two height categories: A = 0 (apical height) and M = 1 (median height) in the Position column.

Once collected in the field, the leaves were quickly transported in plastic bags to the manipulation room, with a semi-controlled acquisition environment to ensure standardized measurement condition, spectra acquisitions being carried out in less than 20 minutes after collection.

Each leaf was placed on a white plate and spectral reflectance data was acquired using a LabSpec® 4i ASD spectrometer and a probe AK100500 with a fixed spot size of 10 mm and operating length of 25.4 cm with an average of 50 individual spectra. The spectral range vary from 350 nm to 2500 nm each 1 nm, columns A to CDS. Note that we first acquired a baseline spectrum on the white plate support before collecting the spectra of the 4 leaves on that plate.

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