Protection of grapevine pruning wounds from infection by Eutypa lata

Background and Aims: Eutypa dieback is a major threat to the sustainability and productivity of the viticulture industry worldwide. The fungicide benomyl has been the most effective treatment to protect wounds against infection by ascospores of Eutypa lata and to control eutypa dieback. However, because of the withdrawal of benomyl from the market, there is a need to develop alternatives to protect pruning wounds. Methods and Results: Twenty-five compounds were evaluated in laboratory experiments and field trials. A selection of the compounds effective at inhibiting germination and/or mycelial growth in the laboratory were further evaluated in the field. Of the 15 fungicides tested, carbendazim was the most effective in reducing colonisation of pruning wounds by E. lata in the field. Other fungicides, including fluazinam, pyrimethanil and pyraclostrobin, reduced colonisation of wounds by E. lata but require further evaluation at higher concentrations. Physical barriers such as acrylic paint (with or without fungicides) and a commercial tree wound paste formulated with fungicides (Garrison) also protected pruning wounds from infection by E. lata. Conclusions: Fungicides and physical barriers have been identified for the control of eutypa dieback in grapevines. The registration of Bavistin (carbendazim) and Garrison is being sought for use on pruning wounds on grapevines in Australia. Significance of the Study: Protection of pruning wounds is essential for the management of eutypa dieback in grapevines. Identification of alternative methods for disease control will provide significant economic benefits for the grapegrowing industry.