Protection of grapevine pruning wounds against Phaeomoniella chlamydospora and Diplodia seriata by commercial biological and chemical methods

The grapevine trunk diseases (GTD) Botryosphaeria dieback and esca threaten the sustainability of the grapevine industry worldwide. This study aimed to evaluate and compare the efficacy of various liquid (pyraclostrobin + boscalid and thiophanate methyl) and paste (paste + tebuconazole) formulation fungicide treatments as well as biological control agents (Trichoderma atroviride SC1 and T. atroviride I-1237), for their potential to prevent infection of grapevine pruning wounds by Diplodia seriata and Phaeomoniella chlamydospora in two field trials over two growing seasons. Treatments were applied to freshly pruned wounds following label dosages’ recommendations. After 24 h, wounds were artificially inoculated with 400 spores of D. seriata or 800 spores of P. chlamydospora. Isolations were made from the treated pruning wounds after 12 months to evaluate the efficacy of the treatments. Fungicide formulations were superior to Trichoderma-based treatments for the control of both pathogens during both growing seasons, with mean percent disease control of 44–95% for D. seriata and 46–67% for P. chlamydospora. Pyraclostrobin + boscalid was the most effective treatment. Trichoderma atroviride-based treatments did not reduce infection by D. seriata or P. chlamydospora compared to the untreated inoculated control in both vineyards and seasons. This study represents the first scientific comparative vineyard assessment of both commercial and biological treatments to protect pruning wounds against GTD fungi in Europe and provides growers with tangible preventative control practices to minimize yield losses due to GTD.

This work has been funded by European funds in collaboration with the ‘Ministerio de Agricultura, Pesca y Alimentación (MAPA)’ (Spanish Government) and the ‘Xunta de Galicia’ (Regional Government) through the project ‘EVID: Innovative practices to combat grapevine diseases’ (FEADER 2017/003B). The authors acknowledge Bodegas Godeval for the provision of field sites and technical assistance for this study. We also thank Dr. J. Luque for the provision of Diplodia seriata isolate JL-398. M.P. Martínez-Diz was supported by the FPI-INIA program from the INIA (Spain, CPD2015-0188). D. Gramaje was supported by the Ramón y Cajal program, Spanish Government (RYC-2017-23098).

Peer reviewed