Pesticide shows promise against vine disease

The West Australian
Research on eutypa dieback has identified effective new treatments.
Camera IconResearch on eutypa dieback has identified effective new treatments. Credit: Countryman

Wine grape growers are closer to protecting high-value vines against the trunk disease eutypa with a registered fungicide that can be applied to pruning wounds with a vineyard sprayer.

A three-year research project on managing eutypa dieback has identified effective new pruning-wound treatments, including the grapevine fungicide Emblem (fluazinam) at rates registered for protectant pre-budburst control of phomopsis.

The collaborative research was conducted by the South Australian Research and Development Institute, the University of Adelaide, and the Grape and Wine Research and Development Corporation.

Crop Care has made a submission to the Australian Pesticide and Veterinary Medicine Authority to register Emblem for eutypa control.

SARDI science leader Dr Mark Sosnowski said having registered eutypa fungicides that can be applied with a sprayer would be an important step in the bid to save Australia's premium vines from trunk disease.

He said trunk disease threatened the long-term sustainability of the Australian wine industry, and the incidence was steadily increasing.

Dr Sosnowski said a GWRDCcommissioned economic study ranked trunk disease as the fourth most important grapevine disease in terms of economic impact behind powdery mildew, downy mildew and botrytis.

"There are many effective registered treatments for the first three, but very little registered for trunk disease, and nothing that can be applied with a commercial sprayer," he said.

"Currently, the only method of controlling eutypa dieback once it is established in vines is by removal of all infected wood tissue.

"A more cost-effective method of control is to prevent disease entry into the vine by protecting wounds."

The fungus infects vines through pruning wounds, and colonises wood tissue causing dieback of cordons, stunting of green shoots, leaf distortion, poor fruit set, uneven berry ripening and eventually death of vines, if not controlled.

Eutypa dieback can be controlled by protecting wounds from infection by the fungus, by physically removing infected wood and retraining watershoots from below the infection, by avoiding pruning in wet conditions and with good vineyard sanitation.

As well as potential treatments, the recent research also looked at the use of commercial sprayers to effectively apply treatments to pruning wounds.

"High-volume recycle sprayers and a home-engineered cordon sprayer maximised spray coverage on the wounds, and provided control equivalent to treatments applied by paintbrush," Dr Sosnowski said.

If this year's APVMA submission is successful, Emblem would be the only fungicide with label registration for Eutypa control that can be applied with a vineyard sprayer.

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