france, gironde, targon, attack of downy mildew on an old vine in the summer of 2023

attaque bordeaux vineyard climate climatologie degat grape bunch mildiou propagation symptom vegetative cycle attack vine disease champignon damage fungus grappe spring weather science agriculture food fruit grapes green mildew nature wine winery countryside farm farmland grapevine hanging harvest industry juicy landscape leaf leaves parasite plant red rural season summer winemaking