Wednesday, May 20, 2015

Eutypa Control - how to limit its spread at pruning time.

  • Control of eutypa dieback can be achieved by protecting wounds from infection by the fungus, Eutypa lata or by physically removing infected wood. 
  • Wounds can be protected with fungicides, paints, pastes and biological control agents. It is also important to time pruning in order to avoid rainfall events and to maintain good sanitation. 
  • Controlling established infections is achieved by removing infected wood and retraining of watershoots from below infection. 
Pruning in wet weather should be avoided and preferably delayed to late winter when wound healing is more rapid and sap flowing.
 
Removal of dead wood from grapevines and alternative hosts in and around the vineyard will reduce the potential inoculum level.
 
The level of infection can be reduced by double pruning, the practice where mechanically pre-pruning is used to leave long spurs in early winter followed by hand-pruning to short spurs in late winter.
 
Contamination of pruning tools is NOT a major means of spreading the disease.

Wound protection

Paints and pastes
The application of acrylic paints and Greenseal paste (containing tebuconazole) are recommended as wound protectants, especially on large wounds. Other treatments such as Gelseal (tebuconazole) and Garrison (cyproconazole + iodocarb) are also effective but are not yet registered for use on grapevines.

Fungicides
Folicur (tebuconazole), Emblem (fluazinam) and Cabrio (pyraclostrobin) are the most effective fungicides tested as wound protectants but are not yet registered for control of eutypa dieback but are registered for other uses in vineyards.

Consult with your winery if you have any concerns about their use.

Use these fungicides at label rate. They can be applied efficiently to pruning wounds with commercial spray machines. It is important to direct nozzles to target the pruning wound zone and use high spray volumes (600 L/ha) to maximise coverage on wounds.

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