Vineyard evaluation of stilbenoid‐rich grape cane extracts against downy mildew: a large‐scale study

Kevin Billet (1) , Guillaume Delanoue (2) , Ingrid Arnault (3) , Sébastien Besseau (1) , Audrey Oudin (1) , Vincent Courdavault (1) , Patrice Marchand (4) , Nathalie Giglioli‐guivarc'H (1) , Laurence Guérin (5) , Arnaud Lanoue (1)

1 BBV EA 2106 - Biomolécules et biotechnologies végétales
2 Val de Loire Centre, Vinopôle Centre Val de Loire
3 IRBI - Institut de recherche sur la biologie de l'insecte UMR7261
4 IPHC - Institut Pluridisciplinaire Hubert Curien
5 Pôle Val de Loire

BACKGROUND: Plasmopara viticola control in organic viticulture requires copper-based fungicides with harmful effects on health and the environment. Plant extracts represent a biorational eco-friendly alternative to copper. The aim of this study was to evaluate the potential of stilbenoid-rich grape cane extract (GCE) against downy mildew on three cultivars over 3 years following natural downy mildew infection. RESULTS: Over all field trials, GCE treatments showed an average reduction in disease incidence of -35% and -38% on leaves and clusters, respectively. The average reduction in disease severity was -35% and -43% on leaves and clusters, respectively. Under artificial downy mildew infection, GCE efficacy corresponded to 1 g L-1 of copper. Neither phytotoxicity nor adverse effects on auxiliary fauna were observed after treatment with GCE. CONCLUSION: Because few or no biocontrol agents are active alone against P. viticola, GCE is a promising alternative to copper-based fungicides. Grape canes, an abundant by-product of viticulture, have great potential for valorization as a biocontrol agent for sustainable viticulture.

Domains: Life Sciences [q-bio]

Kevin Billet, Guillaume Delanoue, Ingrid Arnault, Sébastien Besseau, Audrey Oudin, et al.. Vineyard evaluation of stilbenoid‐rich grape cane extracts against downy mildew: a large‐scale study. Pest Management Science, 2019, 75 (5), pp.1252-1257. ⟨10.1002/ps.5237⟩. ⟨hal-02527716⟩