Quantification of grapevine yield losses as a function of downy mildew severity on foliage and cluster

A 5% downy mildew (DM) severity on grapevine clusters causes a consistent 24% yield loss across multiple years and sites.

• Why it matters: Understanding how disease severity impacts crop yield is crucial for managing grapevine health and optimizing production, especially under varying environmental conditions.
• What they did: A three-year field study near Bordeaux assessed DM severity using AUDPC on foliage and clusters, analyzing its relationship with yield loss at the individual vine level across two sites.
• The result: Yield loss at 5% cluster AUDPC was consistently 24%, while foliar AUDPC at the same level caused variable losses from 9% to 60%, influenced by moisture risk, with higher losses in wetter seasons.