A rapid technique for evaluating treatments for eutypa dieback control (GTD)

Eutypa dieback is a serious fungal disease affecting grapevines in most cool climate wine regions in Australia and internationally. If left unmanaged, the disease reduces yields and eventually kills vines. Typically known as a disease of older vines, recent extensive surveys indicate that eutypa dieback is becoming a threat to youngervines in emerging regions. Spores of the fungus Eutypa lata are produced from fruiting bodies on dead, infected wood and are spread by rainsplash and wind. Infection occurs when spores land on exposed pruning wounds, germinate and eventually colonise the cordons and trunk. Spread of the disease in infected vines can be controlled by the removal of infected wood material (Sosnowski et al. 2009). However, the most effective strategy for preventing the disease is to protect pruning wounds from infection (Sosnowski et al. 2008).
Research has shown that treating pruning wounds with paints and some fungicides can prevent infection. However, the number of fungicides suitable for this treatment is limited and more data must be obtained in order for fungicides to be registered for this purpose. Researchers at the South Australian Research and Development Institute (SARDI), in collaboration with The University of Adelaide, are evaluating methods to optimise management of eutypa dieback, with funding from the Grape and Wine Research and Development Corporation along with additional support from industry. Initial screening of products is carried out in laboratory trials using agar plates amended with different rates of fungicides. This provides efficacy data on potential fungicides in two weeks, but may not reflect effectiveness on grapevine wounds. Field evaluation is imperative for registration but can take up to 15 months to generate data from one experiment. There is a need for a rapid technique to evaluate treatments on grapevine wounds in order to decrease the time taken to generate data for registration.