Research delivers breakthrough in fight to control eutypa disease
Australian grapegrowers can now better manage the disease eutypa dieback with new research identifying a pruning wound treatment that saves time and money and new fungicide sprays.
The new and improved tools in the eutypa defence-kit are part of a recently completed three-year research project, titled Optimising management of eutypa dieback, undertaken by the South Australian Research and Development Institute (SARDI) and funded by the GWRDC.
SARDI research scientist and project leader Dr Mark Sosnowski said the new method would be significantly cheaper and faster than applying pruning wound treatments by hand and, in many cases, would assist growers to better manage the disease.
To date, the most effective and common industry control method is painting pruning wounds by hand, with just two pruning wound treatments registered in Australia for the control of eutypa dieback: Greenseal, a paint containing tebuconazole fungicide, and Vinevax, a trichoderma-based biological control.
The project, conducted by chief investigator Matthew Ayres (SARDI), not only identified a new wound treatment method, it also recognised the need for more registered fungicide treatment options that can be used to prevent infection of pruning wounds and applied with sprayers.
‘We were able to demonstrate that fungicides could be applied effectively to pruning wounds using commercial sprayers, with recycle and purpose-built sprayers being the most efficient’, Dr Sosnowski said.
‘Also, coverage by conventional sprayers designed for foliar spraying can be improved by increasing water spray volume and adjusting nozzles to focus on the pruning wound zone’.
‘And, as a direct result of the project, two fungicides are in the process of label registration for control of eutypa dieback in grapevines.’
The fungicides for which label registration is currently being sought are Folicur (tebuconazole) and Emblem (fluazinam). The research found that Folicur and Emblem, along with Cabrio (pyraclostrobin), are effective for controlling eutypa dieback at the current label rates recommended for other grapevine diseases.
During the project, a new method was developed to assess pruning wound protectants using live single-node cuttings under controlled conditions. This method provides a rapid screening method for new wound treatments , although field trials are still required to assess the ability of treatments to control eutypa dieback.
The outcomes from this project have been communicated through extension activities including workshops and industry publications, and adoption of the new eutypa management strategies is already occurring.
The project’s recommendations will now be addressed in a follow-up project, also funded by the GWRDC, called Practical management of grapevine trunk diseases.
‘We are looking at the susceptibility of pruning wounds to both eutypa and botryosphaeria dieback at different times of the pruning season and the preventative and curative properties of fungicides’, Dr Sosnowski said.
‘As a result, we hope the project will help the industry to be able to make informed decisions on the optimal time to protect pruning wounds’.
The final report is available to read here.